PCI 6150 (HB4)
PCI-to-PCI Bridge
Data Book
PCI 6150 (HB4)
PCI-to-PCI Bridge
Data Book
Version 2.0
May 2003
Website: http://www.plxtech.com
Technical Support: http://www.plxtech.com/support
Phone: 408 774-9060
800 759-3735
Fax: 408 774-2169
© 2003 PLX Technology, Inc. All rights reserved.
PLX Technology, Inc. retains the right to make changes to this product at any time, without
notice. Products may have minor variations to this publication, known as errata. PLX assumes no
liability whatsoever, including infringement of any patent or copyright, for sale and use of PLX
products.
PLX Technology and the PLX logo are registered trademarks of PLX Technology, Inc. Other
brands and names are property of their respective owners.
This device is not designed, intended, authorized, or warranted to be suitable for use in
medical, life-support applications, devices or systems or other critical applications.
PLX Part Number: PCI 6150-BB66PC; Former HiNT Part Number: HB4
Order Number: 6150-SIL-DB-P1-2.0
Printed in the USA, May 2003
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 5
PCI 6150 PCI-to-PCI Bridge
High Performance Asynchronous 66MHz 32-bit PCI-to-PCI Bridge for
Servers, Storage, Telecommunication, Networking and Embedded Applications
PLX’s latest PCI 6150 32-bit PCI-to-PCI bridge is designed for high performance, high availability applications in
hot swap, bus expansions, programmable data transfer rate control, frequency conversions from slower PCI to
faster PCI or from faster PCI to slower PCI buses. PCI 6150 has sophisticated buffer management and buffer
configuration options designed to provide customizable performance optimization.
PCI 6150 has the biggest data FIFO among all 32-bit PCI-to-PCI bridges in the market.
• PCI Local Bus Specification Rev 2.3
support
• High speed PCI buffer supports 3.3V
signaling with 5V input signal tolerance
• Asynchronous design supports standard
66Mhz to 33MHz and faster secondary port
speed such as 33Mhz to 40/50/60/66MHz
conversion
• Programmable Address Translation to
Secondary Bus
• Flow-Through 0 wait state burst up to 4K
bytes for optimal large volume data transfer
• Supports up to 4 simultaneous posted write
transactions and 4 simultaneous Delayed
transactions in each direction
• Provides 1K Bytes of buffering
! 256 byte upstream posted write
buffer
! 256 byte downstream posted write
buffer
! 256 byte upstream read data buffer
! 256 byte downstream read data
buffer
• Programmable prefectch amount of up to
256 bytes for maximum read performance
optimization
• Supports out of order delayed transactions
• CPCI Hot Swap Specification PICMG 2.1
R2.0 with PI = 1 support
• Device Hiding support eliminates mid-
transaction extraction problems
• Serial EEPROM loadable and
programmable PCI READ ONLY Register
configurations.
• External arbiter or programmable arbitration
for 9 bus masters on secondary interface
support
• 10 Secondary clock outputs with pin
controlled enable and individual maskable
control
• Power Management D3 Cold Wakeup
capable
• 4 GPIO pins with output control
• Enhanced address decoding
! Support 32-bit I/O address range
! 32-bit memory-mapped I/O address
range
! ISA aware mode for legacy support in
the first 64KB of I/O address range
! VGA addressing and palette snooping
support
• Provides an IEEE standard 1149.1 JTAG
interface for boundary scan test
• PCI 6150 uses Industry standard 208 pin
PQFP package
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 6
HISTORY
Rev Date Description Eng Chk Mkt Chk
Rev 1.2 5/6/02 PCI 6150 Rev BA1 data book new release.
• Major rewrite of the PCI 6150 data book from previous revisions.
• Updated Hot Swap Capabilities.
Rev 1.21 6/3/02 Added JTAG external pull up/low resistor requirement
Rev 1.22 8/23/02 Update DC characteristic table
Rev 2.0 5/28/03 This release reflects PLX part numbering.
• Added Silicon Revision BB to Section 2
• Section 5, changed pin type in tables for P_SERR#, S_SERR#,
S_REQ#[0], S_GNT#[8:1], S_M66EN, S_CLK[9:0], and
S_RSTOUT#
• Removed Section 6.2, Extended Register Map
• Removed Section 6.3.3, Extended Registers
• Updated Configuration Map in Section 6.1 to reflect deletion of
Extended Registers
• Updated Register DEh, bits 15-11
• Added three notes to table in Section 14.5, Frequency Division
Options
• Updated Section 20.3.1, 24-3Fh
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 7
CONTENTS
HISTORY ................................................................................................................................................................... 6
1 REGISTER INDEX............................................................................................................................................ 11
2 ORDERING INFORMATION ............................................................................................................................ 12
3 USING THE PCI 6150 ...................................................................................................................................... 13
3.1 TRANSPARENT MODE APPLICATION .............................................................................................................. 13
4 PIN DIAGRAM.................................................................................................................................................. 14
5 SIGNAL DEFINITION ....................................................................................................................................... 15
5.1 PRIMARY BUS INTERFACE SIGNALS............................................................................................................... 15
5.2 SECONDARY BUS INTERFACE SIGNALS.......................................................................................................... 17
5.3 CLOCK RELATED SIGNALS............................................................................................................................ 19
5.4 RESET SIGNALS........................................................................................................................................... 19
5.5 MISCELLANEOUS SIGNALS............................................................................................................................ 20
5.6 HOT SWAP SIGNALS..................................................................................................................................... 21
5.7 JTAG/BOUNDARY SCAN INTERFACE SIGNALS ............................................................................................... 21
5.8 POWER SIGNALS.......................................................................................................................................... 21
5.9 PIN ASSIGNMENT SORTED BY LOCATION....................................................................................................... 22
5.10 PIN ASSIGNMENT SORTED BY PIN NAME....................................................................................................... 26
6 CONFIGURATION REGISTERS...................................................................................................................... 30
6.1 CONFIGURATION SPACE MAP ....................................................................................................................... 30
6.2 TRANSPARENT MODE CONFIGURATION REGISTER DESCRIPTION .................................................................... 32
6.2.1 PCI Standard Configuration Registers ............................................................................................... 32
6.2.2 Prefetch Control Registers ................................................................................................................. 43
6.2.3 Hot Swap and Power Management Registers ................................................................................... 54
6.2.4 VPD Registers .................................................................................................................................... 57
7 PCI BUS OPERATION ..................................................................................................................................... 58
7.1 PCI TRANSACTIONS..................................................................................................................................... 58
7.2 SINGLE ADDRESS PHASE ............................................................................................................................. 58
7.3 DUAL ADDRESS PHASE ................................................................................................................................59
7.4 DEVICE SELECT (DEVSEL#) GENERATION................................................................................................... 59
7.5 DATA PHASE................................................................................................................................................ 59
7.5.1 Posted Write Transactions ................................................................................................................. 59
7.5.2 Memory Write and Invalidate Transactions........................................................................................ 60
7.5.3 Delayed Write Transactions ............................................................................................................... 60
7.5.4 Write Transaction Address Boundaries.............................................................................................. 61
7.5.5 Buffering Multiple Write Transactions................................................................................................. 61
7.5.6 Read Transactions ............................................................................................................................. 62
7.5.7 Prefetchable Read Transactions ........................................................................................................ 62
7.5.8 Nonprefetchable Read Transactions.................................................................................................. 62
7.5.9 Read Prefetch Address Boundaries ................................................................................................... 63
7.5.10 Delayed Read Requests .................................................................................................................... 63
7.5.11 Delayed Read Completion with Target............................................................................................... 63
7.5.12 Delayed Read Completion on Initiator Bus ........................................................................................ 64
7.5.13 Configuration Transactions ................................................................................................................ 64
7.5.14 Type-0 Access to PCI 6150................................................................................................................ 65
7.5.15 Type-1 to Type-0 Translation ............................................................................................................. 65
7.5.16 Type-1 to Type-1 Forwarding ............................................................................................................. 66
7.5.17 Special Cycles .................................................................................................................................... 67
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 8
7.6 TRANSACTION TERMINATION ........................................................................................................................ 67
7.6.1 Master Termination Initiated by PCI 6150.......................................................................................... 68
7.6.2 Master Abort Received by PCI 6150 .................................................................................................. 68
7.6.3 Target Termination Received by PCI 6150 ........................................................................................ 69
7.6.4 Target Termination Initiated by PCI 6150 .......................................................................................... 70
8 ADDRESS DECODING .................................................................................................................................... 72
8.1 ADDRESS RANGES....................................................................................................................................... 72
8.2 I/O ADDRESS DECODING.............................................................................................................................. 72
8.2.1 I/O Base and Limit Address Registers ............................................................................................... 72
8.3 ISA MODE ................................................................................................................................................... 73
8.4 MEMORY ADDRESS DECODING ..................................................................................................................... 74
8.4.1 Memory-Mapped I/O Base and Limit Address Registers ................................................................... 74
8.4.2 Prefetchable Memory Base and Limit Address Registers.................................................................. 75
8.5 VGA SUPPORT............................................................................................................................................ 76
8.5.1 VGA Mode .......................................................................................................................................... 76
8.5.2 VGA Snoop Mode............................................................................................................................... 76
9 TRANSACTION ORDERING ........................................................................................................................... 77
9.1 TRANSACTION ORDERING............................................................................................................................. 77
9.1.1 Transactions Governed by Ordering Rules........................................................................................ 77
9.1.2 General Ordering Guidelines.............................................................................................................. 77
9.1.3 Ordering Rules ................................................................................................................................... 78
9.1.4 Data Synchronization ......................................................................................................................... 79
10 ERROR HANDLING ..................................................................................................................................... 80
10.1 ADDRESS PARITY ERRORS ........................................................................................................................... 80
10.2 DATA PARITY ERRORS ................................................................................................................................. 80
10.2.1 Configuration Write Transactions to Configuration Space ................................................................. 80
10.2.2 Read Transactions ............................................................................................................................. 81
10.2.3 Delayed Write Transactions ............................................................................................................... 81
10.2.4 Posted Write Transactions ................................................................................................................. 83
10.3 DATA PARITY ERROR REPORTING SUMMARY ................................................................................................ 84
10.4 SYSTEM ERROR (SERR#) REPORTING......................................................................................................... 87
11 EXCLUSIVE ACCESS .................................................................................................................................. 88
11.1 CONCURRENT LOCKS................................................................................................................................... 88
11.2 ACQUIRING EXCLUSIVE ACCESS ACROSS PCI 6150...................................................................................... 88
11.3 ENDING EXCLUSIVE ACCESS ........................................................................................................................ 89
12 PCI BUS ARBITRATION .............................................................................................................................. 90
12.1 PRIMARY PCI BUS ARBITRATION .................................................................................................................. 90
12.2 SECONDARY PCI BUS ARBITRATION ............................................................................................................. 90
12.2.1 Secondary Bus Arbitration Using the Internal Arbiter......................................................................... 90
12.2.2 Secondary Bus Arbitration using an External Arbiter ......................................................................... 92
12.2.3 Internal Arbitration Parking................................................................................................................. 92
13 GENERAL PURPOSE I/O INTERFACE....................................................................................................... 93
13.1 GPIO CONTROL REGISTERS ........................................................................................................................ 93
14 CLOCKS ....................................................................................................................................................... 94
14.1 PRIMARY AND SECONDARY CLOCK INPUTS.................................................................................................... 94
14.2 SECONDARY CLOCK OUTPUTS...................................................................................................................... 94
14.3 DISABLING UNUSED SECONDARY CLOCK OUTPUTS ....................................................................................... 94
14.3.1 Secondary Clock Control.................................................................................................................... 94
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 9
14.4 USING AN EXTERNAL CLOCK SOURCE........................................................................................................... 95
14.5 FREQUENCY DIVISION OPTIONS .................................................................................................................... 96
14.6 RUNNING SECONDARY PORT FASTER THAN PRIMARY PORT........................................................................... 96
15 FREQUENCY OPERATION ......................................................................................................................... 97
15.1 66-MHZ OPERATION.................................................................................................................................... 97
16 RESET........................................................................................................................................................... 98
16.1 PRIMARY RESET INPUT................................................................................................................................. 98
16.2 SECONDARY RESET OUTPUT........................................................................................................................ 98
16.3 SOFTWARE CHIP RESET............................................................................................................................... 99
16.4 POWER MANAGEMENT INTERNAL RESET ....................................................................................................... 99
16.5 RESET INPUTS TABLE ................................................................................................................................... 99
17 BRIDGE BEHAVIOR .................................................................................................................................. 100
17.1 ABNORMAL TERMINATION (INITIATED BY BRIDGE MASTER) ........................................................................... 100
17.1.1 Master Abort ..................................................................................................................................... 100
17.2 PARITY AND ERROR REPORTING................................................................................................................. 101
17.2.1 Reporting Parity Errors..................................................................................................................... 101
17.3 SECONDARY IDSEL MAPPING.................................................................................................................... 101
18 FLOW THROUGH OPTIMIZATION............................................................................................................ 102
18.1 READ CYCLE OPTIMIZATION ....................................................................................................................... 102
18.1.1 Primary/Secondary Initial Prefetch Count ........................................................................................ 103
18.1.2 Primary/Secondary Incremental Prefetch Count.............................................................................. 103
18.1.3 Primary/Secondary Maximum Prefetch Count ................................................................................. 103
18.2 READ PREFETCH BOUNDARIES ................................................................................................................... 103
19 IEEE 1149.1 COMPATIBLE JTAG CONTROLLER .................................................................................. 104
20 EEPROM..................................................................................................................................................... 105
20.1 AUTO MODE EEPROM ACCESS ................................................................................................................ 105
20.2 EEPROM MODE AT RESET ....................................................................................................................... 105
20.3 EEPROM DATA STRUCTURE..................................................................................................................... 106
20.3.1 EEPROM Address and Corresponding PCI 6150 Register ............................................................. 107
21 VITAL PRODUCT DATA ............................................................................................................................ 108
22 PCI POWER MANAGEMENT .................................................................................................................... 109
23 HOT SWAP ................................................................................................................................................. 110
23.1 HOT SWAP SIGNALS................................................................................................................................... 110
23.2 DEVICE HIDING .......................................................................................................................................... 110
24 PACKAGE SPECIFICATIONS ................................................................................................................... 111
25 ELECTRICAL SPECIFICATIONS .............................................................................................................. 113
25.1 MAXIMUM RATINGS .................................................................................................................................... 113
25.2 FUNCTIONAL OPERATING RANGE................................................................................................................ 113
25.3 DC ELECTRICAL CHARACTERISTICS............................................................................................................ 114
25.4 PCI SIGNAL TIMING SPECIFICATION............................................................................................................ 115
25.4.1 PCI Signal Timing............................................................................................................................. 115
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 10
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 11
1 Register Index
Arbiter Control Register .............................................................38
Bridge Control Register .............................................................36
Cache Line Size Register ..........................................................33
Capability Identifier
Non-transparent, Primary .................................... 54, 55, 56, 57
Chip Control Register
Non-transparent, Primary ......................................................38
Class Code Register..................................................................33
Device ID Register.....................................................................32
Diagnostic Control Register .......................................................38
ECP Pointer...............................................................................35
EEPROM Address.....................................................................48
EEPROM Control ................................................................47, 48
GPIO Input Data Register..........................................................50
GPIO Output Data Register .......................................................50
GPIO Output Enable Register....................................................50
Header Type Register................................................................33
Hot Swap Register
Non-transparent, Primary ......................................................56
Hot Swap Switch
Non-transparent, Primary ......................................................53
I/O Base Address Upper 16 Bits Register ..................................35
I/O Base Register ......................................................................34
I/O Limit Address Upper 16 Bits Register...................................35
I/O Limit Register.......................................................................34
Internal Arbiter Control Register.................................................46
Interrupt Pin Register.................................................................35
Memory Base Register ..............................................................35
Memory Limit Register...............................................................35
Miscellaneous Options...............................................................41
Next Item Pointer
Non-transparent, Primary ..........................................54, 56, 57
P_SERR_L Event Disable Register ...........................................49
P_SERR_L Status Register .......................................................52
PMCSR Bridge Support
Non-transparent, Primary ......................................................55
Power Management Capabilities
Non-transparent, Primary...................................................... 54
Power Management Control/ Status
Non-transparent, Primary...................................................... 55
Prefetchable Memory Base Register ......................................... 35
Prefetchable Memory Base Register Upper 32 Bits................... 35
Prefetchable Memory Limit Register.......................................... 35
Prefetchable Memory Limit Register Upper 32 Bits ................... 35
Primary Bus Number Register................................................... 33
Primary Command Register ...................................................... 32
Primary Flow Through Control Register..................................... 39
Primary Latency Timer Register ................................................ 33
Primary Side Incremental Prefetch Count.................................. 43
Primary Side Maximum Prefetch Count..................................... 44
Primary Side Prefetch Line Count ............................................. 43
Primary Status Register ............................................................ 33
Revision ID Register.................................................................. 33
Secondary Bus Number Register .............................................. 33
Secondary Clock Control Register............................................. 51
Secondary Flow Through Control Register................................ 45
Secondary Latency Timer.......................................................... 34
Secondary Side Incremental Prefetch Count ............................. 44
Secondary Side Maximum Prefetch Count ................................ 44
Secondary Side Prefetch Line Count......................................... 43
Secondary Status Register........................................................ 34
Subordinate Bus Number Register ............................................ 34
Timeout Control Register.......................................................... 40
Vendor ID Register.................................................................... 32
VPD Data Register
Non-transparent, Primary...................................................... 57
VPD Register
Non-transparent, Primary...................................................... 57
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 12
2 Ordering Information
Part Number Rev. Description
PCI 6150 BA 32-bit PCI-to-PCI bridge
PCI 6150 BB 32-bit PCI-to-PCI bridge
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 13
3 Using the PCI 6150
3.1 Transparent Mode Application
Since the PCI 6150 Primary and Secondary ports are asynchronous to each other, the two independent systems
can run at different frequencies. It is possible to run the Secondary bus faster than the Primary bus.
PCI 6150 has powerful programmable buffer control which can be used to regulate data throughput for multiple
PCI masters on the secondary port. The data prefetch size can be programmed to up to 256 bytes.
In Transparent Mode, the host system PCI bus is connected to the PCI 6150 Primary port. The Secondary PCI
port can use either a custom designed external arbiter or the PCI 6150 internal arbiter. Designers can either use
custom designed clock generations, or the PCI 6150 S_CLK[9:0] outputs derived out of the Primary port PCI clock
input or an external oscillator, to provide clocks to secondary PCI devices and the PCI 6150 S_CLKIN input.
The basic design idea is optimized for the following:
S-PORT
PCI 6150
P-PORT
Host System Back-Plane
Secondary Bus
PCI devices
Optional Secondary Clock
source input to the PCI 6150
can be used for all secondary
port PCI devices. This clock
can be asynchronous and
need not be at the same
frequency as the host system
PCI clock input.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 14
4 Pin Diagram
PCI 6150 TOP VIEW
PCI 6150
208
207
201
202
203
206
204
205
200
199
198
197
196
195
194
193
192
191
190
189
188
187
186
185
184
183
182
181
180
179
178
177
176
174
175
173
172
171
170
169
168
167
165
166
164
163
162
161
160
159
158
157
156
155
154
153
152
151
150
149
148
147
146
145
144
143
142
141
140
139
138
137
136
135
134
133
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
2
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
1
28
VDD
S_REQ0_L
S_AD28
VDD
S_AD29
S_AD31
S_AD30
VSS
S_AD27
VSS
S_AD26
S_AD25
VDD
S_AD24
S_CBE3_L
VSS
S_AD23
S_AD22
VDD
S_AD21
S_AD20
VSS
S_AD19
S_AD18
VDD
S_AD17
S_AD16
VSS
S_CBE2_L
S_FRAME_L
VDD
S_IRDY_L
S_TRDY_L
VSS
S_DEVSEL_L
S_STOP_L
S_LOCK_L
S_PERR_L
VDD
S_SERR_L
S_PAR
S_CBE1_L
S_AD15
VSS
S_AD14
VDD
S_AD13
S_AD12
EEPD
S_AD11
EEPCLK
VDD
VSS
GPIO3FN_L
S_AD10
S_M66EN
S_AD9
RESERVED
S_AD8
S_CBE0_L
VSS
S_AD7
S_AD6
VDD
S_AD5
S_AS4
VSS
S_AD3
S_AD2
VDD
S_AD1
S_AD0
VSS
S_VIO
TRST_L
TCLK
TMS
VDD
TDO
TDI
PIN_LED
PIN_ENUM_L
MSK_IN
CFG66
P_VIO
VSS
P_AD0
P_AD1
VDD
P_AD2
P_AD3
VSS
P_AD4
P_AD5
VDD
P_AD6
P_AD7
VSS
P_CBE0_L
P_AD8
VDD
P_AD9
EJECT_EN_L
VDD
VSS
EE_EN_L
P_M66EN
P_AD10
VSS
P_AD11
P_AD12
VDD
P_AD13
P_AD14
VSS
P_AD15
P_CBE1_L
VDD
P_PAR
P_SERR_L
P_PERR_L
P_LOCK_L
VSS
P_STOP_L
P_DEVSEL_L
P_TRDY_L
P_IRDY_L
VDD
P_FRAME_L
P_CBE2_L
VSS
P_AD16
P_AD17
VDD
P_AD18
P_AD19
VSS
P_AD20
P_AD21
VDD
P_AD22
P_AD23
VSS
P_IDSEL
P_CBE3_L
P_AD24
VDD
P_AD25
P_AD26
VSS
P_AD27
P_AD28
VDD
P_AD29
OSC_IN
VDD
VSS
OSC_SEL_L
S_REQ1_L
P_AD30
P_AD31
VSS
P_REQ_L
P_GNT_L
P_CLK
BPCC_EN
P_RST_L
S_CLKOUT9
S_CLKOUT8
VDD
S_CLKOUT7
S_CLKOUT6
VSS
S_CLKOUT5
S_CLKOUT4
VDD
S_CLKOUT3
S_CLKOUT2
VSS
S_CLKOUT1
S_CLKOUT0
GPIO1
VDD
GPIO2
GPIO3
S_CFN_L
S_RST_L
S_CLK
VSS
S_GNT8_L
S_GNT7_L
S_GNT6_L
S_GNT5_L
S_GNT4_L
S_GNT3_L
S_GNT2_L
VSS
S_GNT1_L
S_GNT0_L
S_REQ8_L
S_REQ7_L
S_REQ6_L
S_REQ5_L
S_REQ4_L
S_REQ3_L
S_REQ2_L
VDD
GPIO0
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 15
5 Signal Definition
Signal Types
PI PCI Input (5V signal input tolerant, I/O VDD=3.3V)
PTS PCI Three-state bi-directional (5V signal input tolerant, I/O VDD=3.3V)
PO PCI Output
PSTS PCI Sustained Three-state Output. (5V signal input tolerant, I/O VDD=3.3V)
ICMOS Input
OCMOS Output
IO CMOS Bi-direct
PU Signal is pulled-up internally
PD Signal is pulled-down internally
5.1 Primary Bus Interface Signals
Name Type Description
P_AD[31:0] PTS Primary address/data: Multiplexed address and data bus. Address is
indicated by P_FRAME# assertion. Write data is stable and valid when
P_IRDY# is asserted and read data is stable and valid when P_TRDY# is
asserted. Data is transferred on rising clock edges when both P_IRDY# and
P_TRDY# are asserted. During bus idle, PCI 6150 drives P_AD to a valid
logic level when P_GNT# is asserted.
P_CBE[3:0] PTS Primary command/byte enables: Multiplexed command field and byte
enable field. During address phase, the initiator drives the transaction type
on these pins. After that the initiator drives the byte enables during data
phases. During bus idle, PCI 6150 drives P_CBE[3:0] to a valid logic level
when P_GNT# is asserted.
P_PAR PTS Primary Parity: Parity is even across P_AD[31:0], P_CBE[3:0], and P_PAR
(i.e. an even number of ‘1’s). P_PAR is an input and is valid and stable one
cycle after the address phase (indicated by assertion of P_FRAME#) for
address parity. For write data phases, P_PAR is an input and is valid one
clock after P_IRDY# is asserted. For read data phase, P_PAR is an output
and is valid one clock after P_TRDY# is asserted. Signal P_PAR is three-
stated one cycle after the PAD lines are three-stated. During bus idle, PCI
6150 drives PPAR to a valid logic level when P_GNT# is asserted.
P_FRAME# PSTS Primary FRAME: Driven by the initiator of a transaction to indicate the
beginning and duration of an access. The deassertion of P_FRAME#
indicates the final data phase requested by the initiator. Before being three-
stated, it is driven to a deasserted state for one cycle.
P_IRDY# PSTS Primary IRDY: Driven by the initiator of a transaction to indicate its ability to
complete the current data phase on the primary side. Once asserted in a
data phase, it is not deasserted until end of the data phase. Before being
three-stated, it is driven to a deasserted state for one cycle.
P_TRDY# PSTS Primary TRDY: Driven by the target of a transaction to indicate its ability to
complete the current data phase on the primary side. Once asserted in a
data phase, it is not deasserted until end of the data phase. Before being
three-stated, it is driven to a deasserted state for one cycle.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 16
P_DEVSEL# PSTS Primary Device Select: Asserted by the target indicating that the device is
accepting the transaction. As a master, PCI 6150 waits for the assertion of
this signal within 5 cycles of P_FRAME# assertion; otherwise, terminate with
master abort. Before being three-stated, it is driven to a deasserted state for
one cycle.
P_STOP# PSTS Primary STOP: Asserted by the target indicating that the target is requesting
the initiator to stop the current transaction. Before being three-stated, it is
driven to a deasserted state for one cycle.
P_LOCK# PI Primary LOCK: Asserted by master for multiple transactions to complete. If
LOCK function is not needed, as in the case that no secondary PCI devices
support LOCK, this input should be pulled “HIGH” and should not be
connected to the PCI bus. This function can also be disabled by setting
register 46h bit 13 to 0.
P_IDSEL PI Primary ID Select. Used as chip select line for Type-0 configuration access
to PCI 6150 configuration space.
P_PERR# PSTS Primary Parity Error: Asserted when a data parity error is detected for data
received on the primary interface. Before being three-stated, it is driven to a
deasserted state for one cycle.
P_SERR# OD Primary System Error: Can be driven LOW by any device to indicate a
system error condition.
This signal should be pulled up through an external resistor.
P_REQ# PTS Primary Request: This is asserted by PCI 6150 to indicate that it wants to
start a transaction on the primary bus. PCI 6150 deasserts this pin for at
least 2 PCI clock cycles before asserting it again.
P_GNT# PI Primary Grant: When asserted, PCI 6150 can access the primary bus.
During idle and P_GNT# asserted, PCI 6150 will drive P_AD, P_CBE and
P_PAR to valid logic level.
P_M66EN PI Primary 66 MHz Enable: Set high for 66MHz primary bus. This signal, along
with the S_M66EN signal, controls the frequency output to the SCLKOUT
pins. See Chapter 15 for more details.
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5.2 Secondary Bus Interface Signals
Name Type Description
S_AD[31:0] PTS Secondary Address/Data: Multiplexed address and data bus. Address is
indicated by S_FRAME# assertion. Write data is stable and valid when
S_IRDY# is asserted and read data is stable and valid when S_TRDY# is
asserted. Data is transferred on rising clock edges when both S_IRDY# and
S_TRDY# are asserted. During bus idle, PCI 6150 drives S_AD to a valid
logic level when the S_GNT# is asserted.
S_CBE[3:0] PTS Secondary Command/Byte Enables: Multiplexed command field and byte
enable field. During the address phase, the initiator drives the transaction
type on these pins. After that the initiator drives the byte enables during data
phases. During bus idle, PCI 6150 drives S_CBE[3:0] to a valid logic level
when the internal grant is asserted.
S_PAR PTS Secondary Parity: Parity is even across S_AD[31:0], S_CBE[3:0], and
S_PAR (i.e. an even number of ‘1’s). S_PAR is an input and is valid and
stable one cycle after the address phase (indicated by assertion of
S_FRAME#) for address parity. For write data phases, S_PAR is an input
and is valid one clock after S_IRDY# is asserted. For read data phase,
S_PAR is an output and is valid one clock after S_TRDY# is asserted. Signal
S_PAR is three-stated one cycle after the S_AD lines are three-stated.
During bus idle, PCI 6150 drives S_PAR to a valid logic level when the
internal grant is asserted.
S_FRAME# PSTS Secondary FRAME: Driven by the initiator of a transaction to indicate the
beginning and duration of an access. The deassertion of S_FRAME#
indicates the final data phase requested by the initiator. Before being three-
stated, it is driven to a deasserted state for one cycle
S_IRDY# PSTS Secondary IRDY: Driven by the initiator of a transaction to indicate its ability
to complete the current data phase on the primary side. Once asserted in a
data phase, it is not deasserted until end of the data phase. Before being
three-stated, it is driven to a deasserted state for one cycle.
S_TRDY# PSTS Secondary TRDY: Driven by the target of a transaction to indicate its ability
to complete the current data phase on the primary side. Once asserted in a
data phase, it is not deasserted until end of the data phase. Before being
three-stated, it is driven to a deasserted state for one cycle.
S_DEVSEL# PSTS Secondary Device Select: Asserted by the target indicating that the device
is accepting the transaction. As a master, PCI 6150 waits for the assertion of
this signal within 5 cycles of S_FRAME# assertion; otherwise, terminate with
master abort. Before being three-stated, it is driven to a deasserted state for
one cycle.
S_STOP# PSTS Secondary STOP: Asserted by the target indicating that the target is
requesting the initiator to stop the current transaction. Before being three-
stated, it is driven to a deasserted state for one cycle.
S_LOCK# PSTS Secondary LOCK: Asserted by master to complete multiple transactions.
S_PERR# PSTS Secondary Parity Error: Asserted when a data parity error is detected for
data received on the primary interface. Before being three-stated, it is driven
to a deasserted state for one cycle.
S_SERR# PI Secondary System Error: Can be driven LOW by any device to indicate a
system error condition.
This signal should be pulled up through an external resistor.
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S_REQ#[0] PI Secondary Request 0: When External arbitration is not activated, this is
asserted by external device to indicate that it wants to start a transaction on
the Secondary bus. It must be externally pulled up through resistors to VDD.
When External arbitration is active, this becomes the External Grant input to
PCI 6150.
S_REQ#[8:1] PI Secondary Requests: This is asserted by external device to indicate that it
wants to start a transaction on the Secondary bus. They must be externally
pulled up through resistors to VDD.
S_GNT#[0] PTS Secondary Grant 0: This pin behaves like S_GNT#[8:1] under Transparent
Mode and External arbitration is not activated.
When External arbitration is active, this becomes the External Bus Request
output from PCI 6150.
S_GNT#[8:1] PTS Secondary Grants: PCI 6150 asserts this pin to access the secondary bus.
PCI 6150 deasserts this pin for at least 2 PCI clock cycles before asserting it
again. During idle and S_GNT# asserted, PCI 6150 will drive S_AD, S_CBE
and S_PAR to valid logic levels.
S_M66EN PI/OD Secondary 66 MHz Enable: Drive low if P_M66EN is low, otherwise driven
from outside to select 66MHz or 33MHz. This signal, along with the
P_M66EN signal, controls the frequency output to the S_CLKOUTn pins.
This pin should be pulled High or Low externally.
See Chapter 15 for more details
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5.3 Clock Related Signals
Name Type Description
P_CLKIN I Primary CLK input: Provides timing for all transactions on primary interface.
S_CLKIN I Secondary CLK input: Provides timing for all transactions on secondary
interface.
S_CLK[9:0] PO Secondary CLK output: Provides S_CLKIN or OSCIN (if enabled) phased
shifted synchronous output clocks.
MSK_IN I Secondary Clock Disable Serial Input. This signal is used by the hardware
mechanism to disable secondary clock outputs. The serial stream is received
by MSK_IN, starting when P_RSTIN# is detected deasserted and
S_RSTOUT# is detected asserted. This serial data is used for selectively
disabling secondary clock outputs and is shifted into the secondary clock
control configuration register.
This input can be tied low to enable all secondary clock outputs. If tied high,
the clocks will be active until high after reset. After the “1”s have been shifted
in, the clocks will be driven high.
OSCSEL# I External Oscillator Enable. Enables connection of external clock for the
secondary interface. If low, secondary bus clock outputs will use the clock
signal from OSCIN input instead of P_CLKIN to generate S_CLK[9:0]. If
HIGH, P_CLKIN is used. This pin must NOT be left unconnected.
OSCIN I External Oscillator Input. External clock input used to generate secondary
output clocks when enabled through OSCSEL# pin.
5.4 Reset Signals
Name Type Description
P_RSTIN# PI Primary Reset: When P_RSTIN# is active, outputs are asynchronously
three-stated and P_SERR# and P_GNT# floated. All primary port PCI
standard configuration registers 0h-3Fh revert to their default state.
When asserted, all primary PCI signals are three-stated and no bus
parking is asserted.
S_RSTOUT# PO Secondary Reset Output: Asserted when any of the following conditions is
met:
1. Signal P_RSTIN# is asserted.
2. The Secondary reset bit in the bridge control register (Register 3Eh) in
configuration space is set.
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5.5 Miscellaneous Signals
Name Type Description
S_CFN# I Internal Arbiter Enable:
0 = Use internal arbiter.
1 = Use external arbiter.
S_REQ0# becomes External Arbiter GNT# input and S_GNT0# becomes
REQ# output to External Arbiter.
CFG66 I Primary Config 66MHz: The state of this pin is reflected in the Secondary
status register at offset 1Eh. Other than this, the pin has no effect on PCI
6150 operation.
BPCC_EN I Bus/Power Clock Control Management pin. When signal is tied high and
the PCI 6150 is placed in the D3hot power state, the PCI 6150 places the
secondary bus in the B2 power state. The PCI 6150 disables the secondary
clocks and drives them to 0. When tied low, placing the PCI 6150 in the
D3hot power state has no effect on the secondary bus clocks.
GPIO[3:0] IO-PU General Purpose Input Output pins. These 4 general purpose signals are
programmable as either input-only or bi-directional signals by writing the
GPIO output enable control register. During PRST# asserted, GPIO[3:0] are
used to shift in the clock disable serial data.
EEPCLK O EEPROM Clock. This pin is the clock signal to the EEPROM interface used
during Autoload and for VPD functions.
EEPDATA IO EEPROM Serial Data. This pin is serial data interface to the EEPROM.
EE_EN# I EEPROM Enable. This input should be “0” to enable EEPROM use
PVIO I Primary Interface I/O Voltage This signal must be tied to either 3.3V or 5V,
depending on the signaling voltage of the primary interface.
SVIO I Secondary Interface I/O Voltage This signal must be tied to either 3.3V or
5V, depending on the signaling voltage of the secondary interface.
Pin 151
Reserved
PCI 6150 does not use this pin.
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5.6 Hot Swap Signals
In order to use Hot Swap function, both EJECT_EN# and GPIO3FN# must be connected to “0”.
Name Type Description
ENUM# O Hot Swap Interrupt: An open drain bussed signal to signal a change in
status for the chip. It is asserted through the Hot Swap registers.
LED IO-PD Hot Swap LED: Indicates the status of software connection process. If Hot
Swap is NOT enabled (When either EJECT_EN# or GPIOFN# is “1”), this
pin must be left unconnected or pulled to logic “0” via a 1K pull down
resistor.
GPIO3FN# I
GPIO[3] Function Select: When GPIO3FN# is tied HIGH, GPIO[3] acts
only as a GPIO pin regardless of the state of EJECT_EN#. GPIO[3] acts
as Ejector input only when both GPIO3FN# and EJECT_EN# are tied
LOW.
EJECT_EN# I-PU Eject Enable: Pin used to enable GPIO[3] pin as EJECT input.
If this pin is “1”, GPIO[3] will function as a GPIO pin. GPIO[3] only acts as
EJECT input when both GPIO3FN# and EJECT_EN# are tied LOW.
5.7 JTAG/Boundary Scan Interface Signals
Name Type Description
TCK I-PU Test Clock: Used to clock state information and test data into and out of PCI
6254 during operation of the TAP.
This pin should be pulled high or pulled low to a known state using an
external resistor.
TMS I-PU Test Mode Select: Used to control the state of the TAP controller in PCI
6254.
This pin should be pulled high or pulled low to a known state using an
external resistor.
TDO O Test Data Output: Used to serially shift test data and test instructions out of
PCI 6254 during TAP operation.
TDI I-PU Test Data Input: Used to serially shift test data and test instructions into PCI
6254 during TAP operation.
This pin should be pulled high or pulled low to a known state using an
external resistor.
TRST# I Test Reset: It provides an asynchronous initialization of the TAP controller.
This pin MUST be pulled high or pulled low to a known state using an
external resistor. We recommend pulling low using a 330ohm resistor.
5.8 Power Signals
Name Type Description
VDD +3.3V
GND Ground
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5.9 Pin Assignment Sorted By Location
PIN
NO.
Signal
Name
Type PIN
NO.
Signal
Name
Type PIN
NO.
Signal
Name
Type
1VDD P 36 S_CLKOUT5 O 71 P_AD20 TS
2S_REQ1# I 37 VSS P 72 VSS P
3S_REQ2# I 38 S_CLKOUT6 O 73 P_AD19 TS
4S_REQ3# I 39 S_CLKOUT7 O 74 P_AD18 TS
5S_REQ4# I 40 VDD P 75 VDD P
6S_REQ5# I 41 S_CLKOUT8 O 76 P_AD17 TS
7S_REQ6# I 42 S_CLKOUT9 O 77 P_AD16 TS
8S_REQ7# I 43 P_RST# I 78 VSS P
9S_REQ8# I 44 BPCC_EN I 79 P_CBE2# TS
10 S_GNT0# TS 45 P_CLK I 80 P_FRAME# STS
11 S_GNT1# TS 46 P_GNT# I 81 VDD P
12 VSS P 47 P_REQ# TS 82 P_IRDY STS
13 S_GNT2# TS 48 VSS P 83 P_TRDY STS
14 S_GNT3# TS 49 P_AD31 TS 84 P_DEVSEL# STS
15 S_GNT4# TS 50 P_AD30 TS 85 P_STOP# STS
16 S_GNT5# TS 51 OSC_SEL# I 86 VSS P
17 S_GNT6# TS 52 VSS P 87 P_LOCK# I
18 S_GNT7# TS 53 VDD P 88 P_PERR# STS
19 S_GNT8# TS 54 OSC_IN I 89 P_SERR# OD
20 VSS P 55 P_AD29 TS 90 P_PAR TS
21 S_CLK I 56 VDD P 91 VDD P
22 S_RST# O 57 P_AD28 TS 92 P_CBE1# TS
23 S_CFN# I 58 P_AD27 TS 93 P_AD15 TS
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24 GPIO3 TS 59 VSS P 94 VSS P
25 GPIO2 TS 60 P_AD26 TS 95 P_AD14 TS
26 VDD P 61 P_AD25 TS 96 P_AD13 TS
27 GPIO1 TS 62 VDD P 97 VDD P
28 GPIO0 TS 63 P_AD24 TS 98 P_AD12 TS
29 S_CLKOUT0 O 64 P_CBE3# TS 99 P_AD11 TS
30 S_CLKOUT1 O 65 P_IDSEL I 100 VSS P
31 VSS P 66 VSS P 101 P_AD10 TS
32 S_CLKOUT2 O 67 P_AD23 TS 102 P_M66EN I
33 S_CLKOUT3 O 68 P_AD22 TS 103 EE_EN# I
34 VDD P 69 VDD P 104 VSS P
35 S_CLKOUT4 O 70 P_AD21 TS 105 VDD P
PCI 6150 Data Book v2.0
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Signal Names Sorted By Pin Number (Continue)
PIN
NO.
Signal
Name
Type PIN
NO.
Signal
Name
Type PIN
NO.
Signal
Name
Type
106 EJECT_EN# I 141 S_AD3 TS 176 S_TRDY# STS
107 P_AD9 TS 142 VSS P 177 S_IRDY# STS
108 VDD P 143 S_AD4 TS 178 VDD P
109 P_AD8 TS 144 S_AD5 TS 179 S_FRAME# STS
110 P_CBE0# TS 145 VDD P 180 S_CBE2# TS
111 VSS P 146 S_AD6 TS 181 VSS P
112 P_AD7 TS 147 S_AD7 TS 182 S_AD16 TS
113 P_AD6 TS 148 VSS P 183 S_AD17 TS
114 VDD P 149 S_CBE0# TS 184 VDD P
115 P_AD5 TS 150 S_AD8 TS 185 S_AD18 TS
116 P_AD4 TS 151 Reserved 186 S_AD19 TS
117 VSS P 152 S_AD9 TS 187 VSS P
118 P_AD3 TS 153 S_M66EN OD 188 S_AD20 TS
119 P_AD2 TS 154 S_AD10 TS 189 S_AD21 TS
120 VDD P 155 GPIO3FN# I 190 VDD P
121 P_AD1 TS 156 VSS P 191 S_AD22 TS
122 P_AD0 TS 157 VDD P 192 S_AD23 TS
123 VSS P 158 EEPCLK O 193 VSS P
124 P_VIO I 159 S_AD11 TS 194 S_CBE3# TS
125 CFG66 I 160 EEPD I/O 195 S_AD24 TS
126 MSK_IN I 161 S_AD12 TS 196 VDD P
127 PIN_ENUM# O 162 S_AD13 TS 197 S_AD25 TS
128 PIN_LED I/O 163 VDD P 198 S_AD26 TS
129 TDI I 164 S_AD14 TS 199 VSS P
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130 TDO O 165 S_AD15 TS 200 S_AD27 TS
131 VDD P 166 VSS P 201 S_AD28 TS
132 TMS I 167 S_CBE1# TS 202 VDD P
133 TCLK I 168 S_PAR TS 203 S_AD29 TS
134 TRST# I 169 S_SERR# I 204 S_AD30 TS
135 S_VIO I 170 VDD P 205 VSS P
136 VSS P 171 S_PERR# STS 206 S_AD31 TS
137 S_AD0 TS 172 S_LOCK# STS 207 S_REQ0# I
138 S_AD1 TS 173 S_STOP# STS 208 VDD P
139 VDD P 174 VSS P
140 S_AD2 TS 175 S_DEVSEL# STS
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5.10 Pin Assignment Sorted By Pin Name
Signal
Name PIN
NO.
Type Signal
Name PIN
NO.
Type Signal
Name PIN
NO.
Type
BPCC_EN 44 IP_AD21 70 TS S_AD1 138 TS
CFG66 125 IP_AD22 68 TS S_AD2 140 TS
EE_EN# 103 IP_AD23 67 TS S_AD3 141 TS
EEPCLK 158 OP_AD24 63 TS S_AD4 143 TS
EEPD 160 I/O P_AD25 61 TS S_AD5 144 TS
EJECT_EN# 106 IP_AD26 60 TS S_AD6 146 TS
GPIO0 28 TS P_AD27 58 TS S_AD7 147 TS
GPIO1 27 TS P_AD28 57 TS S_AD8 150 TS
GPIO2 25 TS P_AD29 55 TS S_AD9 152 TS
GPIO3 24 TS P_AD30 50 TS S_AD10 154 TS
GPIO3FN# 155 IP_AD31 49 TS S_AD11 159 TS
MSK 126 I P_CBE0# 110 TS S_AD12 161 TS
OSC_IN 54 I P_CBE1# 92 TS S_AD13 162 TS
OSC_SEL# 51 I P_CBE2# 79 TS S_AD14 164 TS
P_AD0 122 TS P_CBE3# 64 TS S_AD15 165 TS
P_AD1 121 TS P_CLK 45 IS_AD16 182 TS
P_AD2 119 TS P_DEVSEL# 84 STS S_AD17 183 TS
P_AD3 118 TS P_FRAME# 80 STS S_AD18 185 TS
P_AD4 116 TS P_GNT# 46 IS_AD19 186 TS
P_AD5 115 TS P_IDSEL 65 IS_AD20 188 TS
P_AD6 113 TS P_IRDY# 82 STS S_AD21 189 TS
P_AD7 112 TS P_LOCK# 87 IS_AD22 191 TS
P_AD8 109 TS P_M66EN 102 IS_AD23 192 TS
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P_AD9 107 TS P_PAR 90 TS S_AD24 195 TS
P_AD10 101 TS P_PERR# 88 STS S_AD25 197 TS
P_AD11 99 TS P_REQ# 47 TS S_AD26 198 TS
P_AD12 98 TS P_RST# 43 IS_AD27 200 TS
P_AD13 96 TS P_SERR# 89 OD S_AD28 201 TS
P_AD14 95 TS P_STOP# 85 STS S_AD29 203 TS
P_AD15 93 TS P_TRDY# 83 STS S_AD30 204 TS
P_AD16 77 TS P_VIO 124 IS_AD31 206 TS
P_AD17 76 TS PIN_ENUM# 127 O S_CBE0# 149 TS
P_AD18 74 TS PIN_LED 128 I/O S_CBE1# 167 TS
P_AD19 73 TS Reserved 151 S_CBE2# 180 TS
P_AD20 71 TS S_AD0 137 TS S_CBE3# 194 TS
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Signal Names Sorted Alphabetically (Continue)
Signal
Name PIN
NO.
Type Signal
Name PIN
NO.
Type Signal
Name PIN
NO.
Type
S_CFN# 23 IS_REQ7#
8IVDD 182 P
S_CLK 21 IS_REQ8#
9IVDD 190 P
S_CLKOUT0 29 OS_RST# 22 OVDD 196 P
S_CLKOUT1 30 O S_SERR# 169 IVDD 202 P
S_CLKOUT2 32 OS_STOP#173 STS VDD 208 P
S_CLKOUT3 33 O S_TRDY# 176 STS VSS 12 P
S_CLKOUT4 35 OS_VIO 135 I VSS 20 P
S_CLKOUT5 36 OTCLK 133 I VSS 31 P
S_CLKOUT6 38 OTDI 129 I VSS 37 P
S_CLKOUT7 39 OTDO 130 O VSS 48 P
S_CLKOUT8 41 OTMS 132 I VSS 52 P
S_CLKOUT9 42 OTRST# 134 I VSS 59 P
S_DEVSEL# 175 STS VDD 1P VSS 66 P
S_FRAME# 179 STS VDD 26 P VSS 72 P
S_GNT0# 10 TS VDD 34 P VSS 78 P
S_GNT1# 11 TS VDD 40 P VSS 86 P
S_GNT2# 13 TS VDD 53 P VSS 94 P
S_GNT3# 14 TS VDD 56 P VSS 104 P
S_GNT4# 15 TS VDD 62 P VSS 100 P
S_GNT5# 16 TS VDD 69 P VSS 111 P
S_GNT6# 17 TS VDD 75 P VSS 117 P
S_GNT7# 18 TS VDD 81 P VSS 123 P
S_GNT8# 19 TS VDD 91 P VSS 136 P
S_IRDY# 177 STS VDD 97 P VSS 142 P
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S_LOCK# 172 STS VDD 105 P VSS 148 P
S_M66EN 153 OD VDD 108 P VSS 156 P
S_PAR 168 TS VDD 114 P VSS 166 P
S_PERR# 171 STS VDD 120 P VSS 174 P
S_REQ0# 207 IVDD 131 P VSS 181 P
S_REQ1# 2IVDD 139 P VSS 187 P
S_REQ2# 3IVDD 145 P VSS 193 P
S_REQ3# 4IVDD 157 P VSS 199 P
S_REQ4# 5IVDD 163 P VSS 205 P
S_REQ5# 6IVDD 170 P
S_REQ6# 7IVDD 178 P
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6 Configuration Registers
As a PCI bridge, PCI 6150 includes the standard Type-01h Configuration Space header defined in Bridge 1.1.
The following PCI registers are supported by PCI 6150.
6.1 Configuration Space Map
Superscript legend:
1 = Writable when Read Only Register Write Enable bit is set
2 = EEPROM loadable
Bits 31-24 Bits 23-16 Bits 15-8 Bits 7-0 Address
1,2 Device ID 1,2 Vendor ID 00h
Primary Status Primary Command 04h
1,2 Class Code Revision ID 08h
1,2 BIST 1,2 Header Type Primary Latency
Timer
Cache Line Size 0Ch
Reserved 10h – 17h
Secondary Latency
Timer
Subordinate Bus
Number
Secondary Bus
Number
Primary Bus
Number
18h
Secondary Status I/O Limit I/O Base 1Ch
Memory Limit Memory Base 20h
Prefetchable Memory Limit Prefetchable Memory Base 24h
Prefetchable Memory Base Upper 32 Bits 28h
Prefetchable Memory Limit Upper 32 Bits 2Ch
I/O Limit Upper 16 Bits I/O Base Upper 16 Bits 30h
Reserved ECP Pointer 34h
Reserved 38h
Bridge Control Interrupt Pin Reserved 3Ch
Arbiter Control Diagnostic
Control
Chip Control 40h
2 Misc Options 2 Timeout Control 2 Primary Flow
Through Control
44h
2 Secondary
Incremental
Prefetch Count
2 Primary
Incremental
Prefetch Count
2 Secondary
Prefetch Line
Count
2 Primary Prefetch
Line Count
48h
Reserved 2 Secondary Flow
Through Control
2 Secondary
Maximum
Prefetch Count
2 Primary
Maximum
Prefetch Count
4Ch
Reserved Test register Internal Arbiter Control 50h
EEPROM Data EEPROM Address EEPROM control 54h
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Reserved 58h-60h
GPIO[3-0] Input
Data
GPIO[3-0] Output
Enable Control
GPIO[3-0] Output
Data
P_SERR# event
disable
64h
Reserved P_SERR# status Clock Control 68h
Reserved 6Ch-98h
Reserved Reserved Reserved ROR control 9Ch
Reserved A0-CCh
Reserved Reserved Reserved Reserved D0h
Reserved D4h
Reserved D8h
1,2 Power Management Capabilities Next Item Ptr = E4 Capability ID = 01 DCh
1,2 Power
Management Data
PMCSR Bridge
Support
1, 2 Power Management CSR E0h
Reserved HSCSR = 00 Next Item Ptr = E8 Capability ID = 06 E4h
VPD Register = 0000 Next Item Ptr = 00 Capability ID = 03 E8h
VPD Data Register = 0000_0000 ECh
Reserved F0h-FCh
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6.2 Transparent Mode Configuration Register Description
6.2.1 PCI Standard Configuration Registers
Vendor ID Register (Read Only) - Offset 0h
Defaults to 3388(h).
Device ID Register (Read Only) - Offset 2h
Defaults to 0022(h).
(Note: R/W - Read/Write, R/O - Read Only, R/WC - Read/ Write 1 to clear)
Primary Command Register (Read/Write) - Offset 4h
Bit Function Type Description
0 I/O Space
Enable
R/W Controls the bridge’s response to I/O accesses on the primary
interface.
0=ignore I/O transaction
1=enable response to I/O transaction
Reset to 0.
1 Memory
Space Enable
R/W Controls the bridge’s response to memory accesses on the primary
interface.
0=ignore all memory transaction
1=enable response to memory transaction
Reset to 0.
2 Bus Master
Enable
R/W Controls the bridge’s ability to operate as a master on the primary
interface.
0=do not initiate transaction on the primary interface and disable
response to memory or I/O transactions on secondary interface
1=enable the bridge to operate as a master on the primary interface
Reset to 0.
3 Special Cycle
Enable
R/O No special cycle implementation (set to ‘0’).
4 Memory Write
and Invalidate
Enable
R/O Memory write and invalidate not supported (set to ‘0’).
5VGA Palette
Snoop Enable
R/W Controls the bridge’s response to VGA compatible palette accesses.
0=ignore VGA palette accesses on the primary interface
1=enable response to VGA palette writes on the primary interface
(I/O address AD[9:0]=3C6h, 3C8h and 3C9h)
Reset to 0.
6 Parity Error
Enable
R/W Controls the bridge’s response to parity errors.
0=ignore any parity errors
1=normal parity checking performed
Reset to 0.
7 Wait Cycle
Control
R/W PCI 6150 performs address / data stepping (reset to ‘1’).
8 P_SERR#
Enable
R/W Controls the enable for the P_SERR# pin.
0=disable the P_SERR# driver
1=enable the P_SERR# driver
Reset to 0.
9 Fast Back to
Back Enable
R/W 0=no fast back to back transaction
1=reserved. PCI 6150 does not generate Fast Back to Back cycle.
Reset to 0.
10-15 Reserved R/O Reserved. Reset to 0.
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Primary Status Register(Read/Write) – Offset 6h
Bit Function Type Description
0-3 Reserved R/O Reserved (set to ‘0’s).
4 ECP R/O Enhanced Capabilities port. Reads as 1 to indicate PCI 6150
supports an enhanced capabilities list.
5 66MHz R/O Reflects the state of CFG66 input pin. 1 = PCI 6150 is 66Mhz
Capable.
6 UDF R/O No User-Definable Features (set to ‘0’).
7 Fast Back to
Back Capable
R/O Fast back-to-back write capable on primary side (set to ‘1’).
8 Data Parity
Error Detected
R/WC It is set when the following conditions are met:
1. P_PERR# is asserted
2. Bit 6 of Command Register is set
Reset to 0.
9-10 DEVSEL
timing
R/O DEVSEL# timing. Reads as 01b to indicate PCI 6150 responds no
slower than with medium timing
11 Signaled
Target Abort
R/WC Should be set (by a target device) whenever a Target Abort cycle
occurs. Reset to 0.
12 Received
Target Abort
R/WC Set to ‘1’ (by a master device) when transactions are terminated
with Target Abort. Reset to 0.
13 Received
Master Abort
R/WC Set to ‘1’ (by a master) when transactions are terminated with
Master Abort. Reset to 0.
14 Signaled
System Error
R/WC Should be set whenever P_SERR# is asserted. Reset to 0.
15 Detected
Parity Error
R/WC Should be set whenever a parity error is detected regardless of the
state of the bit 6 of command register. Reset to 0.
Revision ID Register (Read Only) – Offset 8h
Defaults to 04h.
Class Code Register (Read Only) – Offset 9h
Defaults to 060400h.
Cache Line Size Register (Read/Write) – Offset 0Ch
This register is used when terminating memory write and invalidate transactions. Memory read prefetching is
controlled by the prefetch count registers.
Only cache line sizes (in units of 32-bits words) which are power of two are valid. Resets to 0.
Primary Latency Timer Register (Read/Write) – Offset 0Dh
This register sets the value for Master Latency Timer which starts counting when the master asserts FRAME#.
Reset to 0.
Header Type Register (Read Only) – Offset 0Eh
Defaults to 1.
BIST Register (Read Only) – Offset 0Fh
This register can be written to by enabling the ROR Write Enable bit at register 9Ch bit 7. Reset to 0.
Primary Bus Number Register (Read/Write) – Offset 18h
Programmed with the number of the PCI bus to which the primary bridge interface is connected. This value is set
with configuration software. Reset to 0.
Secondary Bus Number Register (Read/Write) – Offset 19h
Programmed with the number of the PCI bus to which the secondary bridge interface is connected. This value is
set with configuration software. Reset to 0.
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Subordinate Bus Number Register (Read/Write) –Offset 1Ah
Programmed with the number of the PCI bus with the highest number that is subordinate to the bridge. This value
is set with configuration software. Reset to 0.
Secondary Latency Timer (Read/Write) – Offset 1Bh
This register is programmed in units of PCI bus clocks. Reset to 0. The latency timer checks for master accesses
on the secondary side that remain unclaimed by any target.
I/O Base Register (Read/Write) – Offset 1Ch
This register defines the bottom address of the I/O address range for the bridge. The upper four bits define the
bottom address range used by the chip to determine when to forward I/O transactions from one interface to the
other. These 4 bits correspond to address bits <15:12> and are writeable. The upper 16 bits corresponding to
address bits <31:16> are defined in the I/O base address upper 16 bits register. The address bits <11:0> are
assumed to be 000h. The lower four bits (3:0) of this register set to ‘0001’ (read-only) to indicate 32-bit I/O
addressing. Reset to 0.
I/O Limit Register (Read/Write) – Offset 1Dh
This register defines the top address of the I/O address range for the bridge. The upper four bits define the top
address range used by the chip to determine when to forward I/O transactions from one interface to the other.
These 4 bits correspond to address bits <15:12> and are writeable. The upper 16 bits corresponding to address
bits <31:16> are defined in the I/O limit address upper 16 bits register. The address bits <11:0> are assumed to
be FFFh. The lower four bits (3:0) of this register set to ‘0001’ (read-only) to indicate 32-bit I/O addressing. Reset
to 0.
Secondary Status Register (Read/Write) – Offset 1Eh
Bit Function Type Description
0-4 reserved R/O Reserved (set to ‘0’s).
5 66MHz R/O Defaults to 1. PCI 6150 is 66Mhz Capable.
6 UDF R/O No User-Definable Features (set to ‘0’).
7 Fast Back to
Back Capable
R/O Fast back-to-back write capable on secondary port (set to ‘1’).
8 Data Parity
Error Detected
R/WC It is set when the following conditions are met:
1. SPERR# is asserted
2. Bit 6 of Command Register is set
Reset to 0.
9-10 DEVSEL
timing
R/O Medium DEVSEL# timing (set to ‘01’)
11 Signaled
Target Abort
R/WC Should be set (by a target device) whenever a Target Abort cycle
occurs. Should be ‘0’ after reset.
Reset to 0.
12 Received
Target Abort
R/WC Set to ‘1’ (by a master device) when transactions are terminated
with Target Abort.
Reset to 0.
13 Received
Master Abort
R/WC Set to ‘1’ (by a master) when transactions are terminated with
Master Abort.
Reset to 0.
14 Received
System Error
R/WC Should be set whenever SSERR# is detected. Should be a ‘0 after
reset.
Reset to 0.
15 Detected
Parity Error
R/WC Should be set whenever a parity error is detected regardless of the
state of the bit 6 of command register.
Reset to 0.
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Memory Base Register (Read/Write) – Offset 20h
This register defines the base address of the memory-mapped address range for forwarding the cycle through the
bridge. The upper twelve bits corresponding to address bits <31:20> are writeable. The lower 20 address bits
(19:0) are assumed to be 00000h. The 12 bits are reset to 0. The lower 4 bits are read only and set to 0.
Memory Limit Register (Read/Write) – Offset 22h
This register defines the upper limit address of the memory-mapped address range for forwarding the cycle
through the bridge. The upper twelve bits corresponding to address bits <31:20> are writeable. The 12 bits are
reset to 0. The lower 4 bits are read only and are set to 0. The lower 20 address bits (19:0) are assumed to be
FFFFFh. Reset to 0.
Prefetchable Memory Base Register (Read/Write) - Offset 24h
This register defines the base address of the prefetchable memory-mapped address range for forwarding the
cycle through the bridge. The upper twelve bits corresponding to address bits <31:20> are writeable. The 12 bits
are reset to 0. The lower 4 bits are read only and are set to 0. The lower 20 address bits (19:0) are assumed to be
00000h. Reset to 0.
Prefetchable Memory Limit Register (Read/Write) – Offset 26h
This register defines the upper limit address of the memory-mapped address range for forwarding the cycle
through the bridge. The upper twelve bits correspond to address bits <31:20> are writeable. The 12 bits are reset
to 0. The lower 4 bits are read only and are set to 0. The lower 20 address bits (19:0) are assumed to be FFFFFh.
Reset to 0.
Prefetchable Memory Base Register Upper 32 Bits (Read/Write) – Offset 28h
This register defines the upper 32 bit <63:32> memory base address of the prefetchable memory-mapped
address for forwarding the cycle through the bridge. Reset to 0.
Prefetchable Memory Limit Register Upper 32 Bits (Read/Write) – Offset 2Ch
This register defines the upper 32 bit <63:32> memory limit address of the prefetchable memory-mapped address
for forwarding the cycle through the bridge. Reset to 0.
I/O Base Address Upper 16 Bits Register (Read/Write) – Offset 30h
This register defines the upper 16 bits of a 32-bit base I/O address range used for forwarding the cycle through
the bridge. Reset to 0.
I/O Limit Address Upper 16 Bits Register (Read/Write) – Offset 32h
This register defines the upper 16 bits of a 32-bit limit I/O address range used for forwarding the cycle through the
bridge. Reset to 0.
ECP Pointer (Read/Only) – Offset 34h
Bit Function Type Description
7-0 ECP Pointer R/O Enhanced capabilities port offset pointer. This register reads as DCh
to indicate the offset of the power management registers.
Interrupt Pin Register (Read Only) – Offset 3Dh
Reads as 0 to indicate that PCI 6150 does not use any interrupt pin.
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Bridge Control Register (Read/Write) – Offset 3Eh
Bit Function Type Description
0 Parity Error
Response
Enable
R/W Controls the bridge’s response to parity errors on the secondary
interface.
0=ignore address and data parity errors on the secondary interface
1=enable parity error reporting and detection on the secondary
interface
Reset to 0.
1 S_SERR#
Enable
R/W Controls the forwarding of S_SERR# to the primary interface.
0=disable the forwarding S_SERR# to primary
1=enable the forwarding of S_SERR# to primary
Reset to 0.
2 ISA Enable R/W Controls the bridge’s response to ISA I/O addresses, which is limited
to the first 64K.
0=forward all I/O addresses in the range defined by the I/O Base
and I/O Limit registers
1=block forwarding of ISA I/O addresses in the range defined by the
I/O Base and I/O Limit registers that are in the first 64K of I/O space
that address the last 768 bytes in each 1Kbytes block. Secondary
I/O transactions are forwarded upstream if the address falls within
the last 768 bytes in each 1Kbytes block
There is an ISA Enable Control bit Write Protect mechanism
control by EEPROM. When the ISA Enable Control bit Write
Protect bit is set in the EEPROM and EEPROM initialization is
enabled, PCI 6150 will change this bit to read only and ISA Enable
feature will not be available.
Reset to 0.
3 VGA Enable R/W Controls the bridge’s response to VGA compatible addresses.
0=do not forward VGA compatible memory and I/O addresses from
primary to secondary
1=forward VGA compatible memory and I/O address from primary to
secondary regardless of other settings
Reset to 0.
4 reserved R/O Reserved (set to 0).
5 Master Abort
Mode
R/W Controls the bridge behavior in responding to master aborts on
secondary interface
0=do not report master aborts (return ffff_ffffh on reads and discards
data on writes)
1=report master aborts by signaling target abort
Reset to 0.
Note: During lock cycles, PCI 6150 ignores this bit, and always
completes the cycle as a target abort.
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6 Secondary
Reset
R/W Forces the assertion of S_RSTOUT# signal pin on the secondary
interface.
0=do not force the assertion of S_RSTOUT# pin
1=force the assertion of S_RSTOUT# pin
Reset to 0.
7 Fast Back to
Back Enable
R/W 0 = no fast back to back transaction
1= reserved. PCI 6150 does not generate Fast Back to Back cycle.
Reset to 0.
8 Primary
Master
Timeout
R/W Sets the maximum number of PCI clock for an initiator on the
primary bus to repeat the delayed transaction request.
0=Timeout after 215 PCI clocks
1=Timeout after 210 PCI clocks
Reset to 0.
9 Secondary
Master
Timeout
R/W Sets the maximum number of PCI clock for an initiator on the
secondary bus to repeat the delayed transaction request.
0=Timeout after 215 PCI clocks
1=Timeout after 210 PCI clocks
Reset to 0.
10 Master
Timeout
Status
R/WC Set to ‘1’ when either primary master timeout or secondary master
timeout.
Reset to 0.
11 Master
Timeout
P_SERR#
enable
R/W Enable P_SERR# assertion during master timeout.
0=P_SERR# not asserted on master timeout
1=P_SERR# asserted on either primary or secondary master
timeout.
Reset to 0.
15-12 reserved R/O Reserved
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Chip Control Register (Read/Write) – Offset 40h
Bit Function Type Description
0 Reserved R/O
1 Memory write
disconnect
control
R/W Controls when the chip as a target disconnects memory
transactions. When 0, disconnects on queue full or on a 4KB
boundary. When 1, disconnects on a cache line boundary, as well as
when the queue fills or on a 4 KB boundary. Reset value is 0.
2-3 Reserved R/W Default to 0 and must not be changed
4 Secondary
bus prefetch
disable
R/W Controls PCI 6150’s ability to prefetch during upstream memory read
transactions. When 0 the chip prefetches and does not forward byte
enable bits during memory read transactions. When 1, PCI 6150
requests only one Dword from the target during memory read
transactions and forwards read enable bits. PCI 6150 returns a
target disconnect to the requesting master on the first data transfer.
Memory read line and memory read multiple transactions are still
prefetchable. Reset to 0.
7:5 Reserved R/O Reserved (Set to 0)
Diagnostic Control Register (Read/Write) – Offset 41h
Bit Function Type Description
0 Chip reset R/W Chip and Secondary bus reset. Setting this bit will do a chip reset
without asserting S_RSTOUT# and forces secondary reset bit in
bridge control register to be set. After resetting all bits except for the
secondary reset bit in bridge control register, this bit will be cleared.
Write 0 has no effect.
2:1 Test mode R/W Reserved
3 Secondary
Reset output
mask
R/W 1 = Primary reset input P_RSTIN# active will not cause secondary
reset output S_RSTOUT# to become active.
7:4 Reserved R/O Reserved (Set to 0).
Arbiter Control Register (Read/Write) – Offset 42h
Bit Function Type Description
8-0 Arbiter Control R/W Each bit controls whether a secondary bus master is assigned to the
high priority group or the low priority group. Bits <8:0> correspond to
request inputs S_REQ#[8:0], respectively. Reset value is 0.
9 PCI 6150
priority
R/W Defines whether the secondary port of PCI 6150 is in high priority
group or the low priority group
0=low priority group
1=high priority group.
Reset to 1.
15:10 reserved R/O Reserved (set to ‘0’s)
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Primary Flow Through Control Register - Offset 44h
Bit Function Type Description
2-0 Primary
posted write
completion
wait count
R/W Maximum number of clocks that PCI 6150 will wait for posted write
data from initiator if delivering write data in flow through mode and
internal post write queues are almost empty. If the count is
exceeded without any additional data from the initiator, the cycle to
target will be terminated to be completed later.
000 : PCI 6150 will terminate cycle if there is only 1 data entry left in
the internal write queue.
001 : PCI 6150 will deassert IRDY#, and wait 1 clock for data before
terminating cycle.
…
111 : PCI 6150 will wait 7 clocks for source data.
3 Reserved R/O Reserved. Returns 0 when read
6-4 Primary
delayed read
completion
wait count
Maximum number of clocks that PCI 6150 will wait for delayed read
data from target if returning read data in flow through mode and
internal delayed read queue is almost full. If the count is exceeded
without any additional space in the queue, the cycle to target will be
terminated, and completed when initiator retries the rest of the cycle.
000 : PCI 6150 will terminate cycle if only 1 data entry is left in the
read queue.
001 : PCI 6150 will deassert TRDY#, and wait 1 clock for data
before terminating cycle.
…
111 : PCI 6150 will wait 7 clocks for source data.
7 Reserved R/O Reserved. Returns 0 when read.
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Timeout Control Register - Offset 45h
Bit Function Type Description
2-0 Maximum
retry counter
control
R/W Controls maximum number of times that PCI 6150 will retry a cycle
before signaling a timeout. This timeout applies to Read/Write retries
and can be enabled to trigger SERR# on the primary or secondary
port depending the SERR# events that are enabled.
Maximum number of retries to timeout =
0000 : 224
0001 : 218
0010 : 212
0011 : 26
0111 : 20
Reset to 0.
3 Reserved R/O
5:4 Primary
master
timeout divider
R/W Provides an additional option for the primary master timeout.
Timeout counter can optionally be divided by 256, in addition to its
original setting in the Bridge Control register.
Original setting is 32K by default and programmable to 1K.
11 : timeout counter = Primary master timeout / 256
10 : timeout counter = Primary master timeout / 16
01 : timeout counter = Primary master timeout / 8
00: counter = Primary master timeout / 1
defaults to 0
7:6 Secondary
master
timeout divider
R/W Provides an additional option for the secondary master timeout.
Timeout counter can optionally be divided by 256, in addition to its
original setting in the Bridge Control register.
Original setting is 32K by default and programmable to 1K.
11 : timeout counter = Primary master timeout / 256
10 : timeout counter = Primary master timeout / 16
01 : timeout counter = Primary master timeout / 8
00: counter = Primary master timeout / 1
defaults to 0
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Miscellaneous Options - Offset 46h
Bit Function Type Description
0Write
completion
wait for
PERR#
R/W If 1, PCI 6150 will always wait for PERR# status of the target before
completing a delayed write transaction to the initiator.
Defaults to 0
1 Read
completion
wait for PAR
R/W If 1, PCI 6150 will always wait for PAR status of the target before
completing a delayed read transaction to the initiator.
Defaults to 0
2 DTR out of
order enable
R/W If 1, PCI 6150 may return delayed read transactions in a different
order than requested. Otherwise, delayed read transactions are
returned in the same order as requested
Defaults to 0
3 Generate
parity enable
R/W If 1, PCI 6150 as a master will generate the PAR to cycles going
across the bridge, otherwise, PCI 6150 passes along the PAR of the
cycle as stored in the internal buffers.
Defaults to 0
6-4 Address step
control
R/W During configuration type 0 cycles, PCI 6150 will drive the address
for the number of clocks specified in this register before asserting
FRAME#.
000 : PCI 6150 will assert FRAME# at the same time as the
address.
001 : PCI 6150 will assert FRAME# 1 clock after it drives the
address.
…
111 : PCI 6150 will assert FRAME# 7 clocks after it drives the
address.
8-7 Reserved R/W Defaults to 0
9 Prefetch early
termination
R/W If 1, PCI 6150 will terminate prefetching at the current calculated
count if flow through is not yet achieved, and another prefetchable
read cycle is accepted by the PCI 6150.
If 0, PCI 6150 will always finish prefetching as programmed at the
prefetch count registers, regardless of any other outstanding
prefetchable reads in the transaction queue.
10 Read
minimum
enable
R/W If 1, PCI 6150 will only initiate read cycles if there is available space
in the FIFO as specified by the prefetch count registers.
11 Reserved R/O Reserved at 0
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12 Memory write
and invalidate
control
R/W If 1, PCI 6150 will pass memory write and invalidate commands if
there is at least 1 cache line of FIFO space available, otherwise it
will complete as a memory write cycle.
If 0, PCI 6150 will retry memory write and invalidate commands if
there is no space for 1 cache line of data in the internal queues.
Defaults to 0
13 Primary Lock
Enable
R/W If 1, PCI 6150 will follow the LOCK protocol on the primary interface.
Otherwise, LOCK is ignored.
Defaults to 1
14 Secondary
Lock Enable
R/W If 1, PCI 6150 will follow the LOCK protocol on the secondary
interface. Otherwise, LOCK is ignored.
Defaults to 0
15 Reserved R/O Reserved at 0
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6.2.2 Prefetch Control Registers
Registers 44h, 48h – 4Dh are the prefetch control registers, and are used to fine-tune memory read prefetch
behavior of the PCI 6150. Detailed descriptions of these registers can be found in Chapter 18 Flow Through
Optimization.
Primary Initial Prefetch Count - Offset 48h
Bit Function Type Description
5-0 Primary initial
prefetch count
R/W Controls initial prefetch count on the Primary bus during reads to
prefetchable memory space. This register value should be a power
of 2 (only one bit should be set to 1 at any time). Value is number of
double words. Bit 0 is read only and is always 0.
Defaults to 10h
7-6 Reserved R/O Reserved. Returns 0 when read
Secondary Initial Prefetch Count - Offset 49h
Bit Function Type Description
5-0 Secondary
initial prefetch
count
R/W Controls initial prefetch count on the Secondary bus during reads to
prefetchable memory space. This register value should be a power
of 2 (only one bit should be set to 1 at any time). Value is number of
double words. Bit 0 is read only and is always 0.
Defaults to 10h
7-6 Reserved R/O Reserved. Returns 0 when read
Primary Incremental Prefetch Count - Offset 4Ah
Bit Function Type Description
5-0 Primary
incremental
prefetch count
R/W This controls incremental read prefetch count. When an entry’s
remaining prefetch Dword count falls below this value, the bridge will
prefetch an additional “Primary incremental prefetch count” Dwords.
This register value should be a power of 2 (only one bit should be
set to 1 at any time). Value is number of double words. Bit 0 is read
only and is always 0.
This register value must not exceed half the value programmed in
the Primary Maximum Prefetch Count register. Otherwise, no
incremental prefetch will be performed.
Defaults to 10h
7-6 Reserved R/O Reserved. Returns 0 when read
PCI 6150 Data Book v2.0
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Secondary Incremental Prefetch Count - Offset 4Bh
Bit Function Type Description
5-0 Secondary
incremental
prefetch count
R/W This controls incremental read prefetch count. When an entry’s
remaining prefetch Dword count falls below this value, the bridge will
prefetch an additional “Secondary incremental prefetch count”
Dwords. This register value should be a power of 2 (only one bit
should be set to 1 at any time). Value is number of double words. Bit
0 is read only and is always 0.
This register value must not exceed half the value programmed in
the Secondary Maximum Prefetch Count register. Otherwise, no
incremental prefetch will be performed.
Defaults to 10h
7-6 Reserved R/O Reserved. Returns 0 when read
Primary Maximum Prefetch Count - Offset 4Ch
Bit Function Type Description
5-0 Primary
maximum
prefetch count
R/W This value limits the cumulative maximum count of prefetchable
Dwords that are allocated to one entry on the primary when flow
through for that entry was not achieved. This register value should
be an even number. Bit 0 is read only and is always 0.
Exception: 0h = 256 bytes = maximum programmable count
Defaults to 20h
7-6 Reserved R/O Reserved. Returns 0 when read
Secondary Maximum Prefetch Count - Offset 4Dh
Bit Function Type Description
5-0 Secondary
maximum
prefetch count
R/W Register limits the cumulative maximum count of prefetchable
Dwords that are allocated to one entry on the secondary when flow
through for that entry was not achieved. This register value should
be an even number. Bit 0 is read only and is always 0.
Exception: 0h = 256 bytes = maximum programmable count
Defaults to 20h
7-6 Reserved R/O Reserved. Returns 0 when read
PCI 6150 Data Book v2.0
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Secondary Flow Through Control Register - Offset 4Eh
Bit Function Type Description
2-0 Secondary
posted write
completion
wait count
R/W Maximum number of clocks that PCI 6150 will wait for posted write
data from initiator if delivering write data in flow through mode and
internal post write queues are almost empty. If the count is
exceeded without any additional data from the initiator, the cycle to
target will be terminated, to be completed later.
000 : PCI 6150 will terminate cycle if there is only 1 data entry left in
the internal write queue.
001 : PCI 6150 will deassert IRDY#, and wait 1 clock for data before
terminating cycle.
…
111 : PCI 6150 will wait 7 clocks for source data.
3 Reserved R/O Reserved. Returns 0 when read
6-4 Secondary
delayed read
completion
wait count
Maximum number of clocks that PCI 6150 will wait for delayed read
data from target if returning read data in flow through mode and
internal delayed read queue is almost full. If the count is exceeded
without any additional space in the queue, the cycle to target will be
terminated, and completed when initiator retries the rest of the cycle.
000 : PCI 6150 will terminate cycle if only 1 data entry is left in the
read queue.
001 : PCI 6150 will deassert TRDY#, and wait 1 clock for data
before terminating cycle.
…
111 : PCI 6150 will wait 7 clocks for source data.
7 Reserved R/O Reserved. Returns 0 when read.
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Internal Arbiter Control Register - Offset 50h
Bit Function Type Description
0 Low priority
group fixed
arbitration
R/W If 1, the low priority group uses the fixed priority arbitration scheme,
otherwise a rotating priority arbitration scheme is used
Defaults to 0
1 Low priority
group
arbitration
order
R/W This bit is only valid when the low priority arbitration group is set to a
fixed arbitration scheme. If 1, priority decreases in ascending
numbers of the master, for example master #4 will have higher
priority than master #3. If 0, the reverse is true. This order is relative
to the master with the highest priority for this group, as specified in
bits 7-4 of this register.
Defaults to 0
2 High priority
group fixed
arbitration
R/W If 1, the high priority group uses the fixed priority arbitration scheme,
otherwise a rotating priority arbitration scheme is used
Defaults to 0
3 High priority
group
arbitration
order
R/W This bit is only valid when the high priority arbitration group is set to
a fixed arbitration scheme. If 1, priority decreases in ascending
numbers of the master, for example master #4 will have higher
priority than master #3. If 0, the reverse is true. This order is relative
to the master with the highest priority for this group, as specified in
bits 11-8 of this register.
Defaults to 0
7-4 Highest
priority master
in low priority
group
R/W Controls which master in the low priority group has the highest
priority. It is valid only if the group uses the fixed arbitration scheme.
0000 : master#0 has highest priority
0001 :
…
1001 : PCI 6150 has highest priority
1010-1111 : Reserved
Defaults to 0
11-8 Highest
priority master
in high priority
group
R/W Controls which master in the high priority group has the highest
priority. It is valid only if the group uses the fixed arbitration scheme.
0000 : master#0 has highest priority
0001 :
…
1001 : PCI 6150 has highest priority
1010-1111 : Reserved
Defaults to 0
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12-15 Bus Parking
Control
R/W Controls bus grant behavior during idle.
0000 : Last master granted is parked
0001 : Master #0 is parked
…
1001 : Master #8 is parked
1010 : PCI 6150 is parked
other : grant is deasserted
Defaults to 0
PCI 6150 Test Register – Offset 52h
Bit Function Type Description
0EEPROM
Autoload
control
R/W If 1, disables EEPROM autoload
1 Fast EEPROM
Autoload
R/W If 1, speeds up EEPROM autoload by 32 times.
2EEPROM
autoload
status
R/O Status of EEPROM autoload
3-7 Reserved R/O Reserved
PCI 6150 Data Book v2.0
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EEPROM Control - Offset 54h
Bit Function Type Description
0 Start R/W Starts the EEPROM read or write cycle.
1EEPROM
command
R/W Controls the command sent to the EEPROM
1 : write
0 : read
2EEPROM
Error
R/O This bit is set to 1 if EEPROM ACK was not received during
EEPROM cycle.
3EEPROM
autoload
successful
R/O This bit is set to 1 if EEPROM autoload occurred successfully after
reset, and some configuration registers were loaded with values
programmed in the EEPROM. If zero, EEPROM autoload was
unsuccessful or was disabled.
5-4 Reserved R/O Reserved. Returns ‘0’ when read.
7-6 EEPROM
clock rate
R/W Controls frequency of EEPROM clock. EEPROM clock is derived
from the primary PCI clock.
00 = PCLK/1024 (Used for 66Mhz PCI)
01 = PCLK/512
10 = PCLK/256
11 = PCLK/32 (for test mode use)
defaults to 00
EEPROM Address - Offset 55h
Bit Function Type Description
0 Reserved R/O Starts the EEPROM read or write cycle.
7-1 EEPROM
address
R/W Word address for EEPROM cycle.
EEPROM Control - Offset 56h
Bit Function Type Description
15-0 EEPROM
Data
R/W Contains data to be written to the EEPROM. During reads, this
register contains data received from the EEPROM after a read cycle
has completed.
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P_SERR# Event Disable Register - Offset 64h
Bit Function Type Description
0 Reserved R/O Reserved. Returns 0 when read
1Posted write
parity error
R/W Controls ability of PCI 6150 to assert P_SERR# when a data parity
error is detected on the target bus during a posted write transaction.
P_SERR# is asserted if this event occurs when this bit is 0 and
SERR# enable bit in the command register is set.
Reset value is 0.
2Posted
Memory write
nondelivery
R/W Controls ability of PCI 6150 to assert P_SERR# when it is unable to
deliver posted write data after 224 (or programmed Maximum Retry
count at Timeout Control Register) attempts. P_SERR# is asserted if
this event occurs when this bit is 0 and SERR# enable bit in the
command register is set.
Reset value is 0.
3 Target abort
during posted
write
R/W Controls ability of PCI 6150 to assert P_SERR# when it receives a
target abort when attempting to deliver posted write data. P_SERR#
is asserted if this event occurs when this bit is 0 and SERR# enable
bit in the command register is set.
Reset value is 0.
4 Master abort
on posted
write
R/W Controls ability of PCI 6150 to assert P_SERR# when it receives a
master abort when attempting to deliver posted write data.
P_SERR# is asserted if this event occurs when this bit is 0 and
SERR# enable bit in the command register is set.
Reset value is 0.
5 Delayed
Configuration
or IO write
nondelivery
R/W Controls ability of PCI 6150 to assert P_SERR# when it is unable to
deliver delayed write data after 224 (or programmed Maximum Retry
count at Timeout Control Register) attempts. P_SERR# is asserted if
this event occurs when this bit is 0 and SERR# enable bit in the
command register is set.
Reset value is 0.
6 Delayed read-
no data from
target
R/W Controls ability of PCI 6150 to assert P_SERR# when it is unable to
transfer any read data from the target after 224 (or programmed
Maximum Retry count at Timeout Control Register) attempts.
P_SERR# is asserted if this event occurs when this bit is 0 and
SERR# enable bit in the command register is set.
Reset value is 0.
7 Reserved R/O Reserved. Returns 0 when read.
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GPIO[3:0] Output Data Register - Offset 65h
Bit Function Type Description
3:0 GPIO[3:0]
output write 1
to clear
R/W1
TC
Writing 1 to any of these bits drives the corresponding bit low on the
GPIO[3:0] bus if it is programmed as output. Writing 0 has no effect.
Read returns the last written value.
Resets to 0.
7:4 GPIO[3:0]
output write 1
to set
R/W1
TC
Writing 1 to any of these bits drives the corresponding bit high on the
GPIO[3:0] bus if it is programmed as output. Writing 0 has no effect.
Read returns the last written value.
Resets to 0.
GPIO[3:0] Output Enable Register - Offset 66h
Bit Function Type Description
3:0 GPIO output
enable write 1
to clear
R/W1
TC
Writing 1 to any of these bits drives the corresponding bit on the
GPIO[3:0] bus as input only. Writing 0 has no effect.
Read returns the last value written.
Resets to 0.
7:4 GPIO output
enable write 1
to set
R/W1
TC
Writing 1 to any of these bits drives the corresponding bit on the
GPIO[3:0] bus as output. GPIO[3:0] then drives the value set in the
output data register (reg 65h). Writing 0 has no effect.
Read returns the last written value.
Resets to 0.
GPIO[3:0] Input Data Register - Offset 67h
Bit Function Type Description
3:0 Reserved R/O Reserved
7:4 GPIO[3:0]
input data
R/O This read-only register reads the state of the GPIO[3:0] pins. The
state is updated on the PCI clock cycle following a change in the
GPIO[3:0] state.
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Clock Control Register (Read/Write) – Offset 68h
Bit Function Type Description
1:0 Clock 0
Disable
R/W If either bit is 0, S_CLKOUT[0] is enabled.
When both bits are 1, S_CLKOUT[0] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream. These bits are assigned to correspond to the PRSNT#
pins for slot 0.
3:2 Clock 1
Disable
R/W If either bit is 0, S_CLKO[1] is enabled.
When both bits are 1, S_CLKO[1] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream. These bits are assigned to correspond to the PRSNT#
pins for slot 1.
5:4 Clock 2
Disable
R/W If either bit is 0, S_CLKO[2] is enabled.
When both bits are 1, S_CLKO[2] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream. These bits are assigned to correspond to the PRSNT#
pins for slot 2.
7:6 Clock 3
Disable
R/W If either bit is 0, S_CLKO[3] is enabled.
When both bits are 1, S_CLKO[3] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream. These bits are assigned to correspond to the PRSNT#
pins for slot 3.
8 Clock 4
Disable
R/W If 0, S_CLKO[4] is enabled.
When 1, S_CLKO[4] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream.
9 Clock 5
Disable
R/W If 0, S_CLKO[5] is enabled.
When 1, S_CLKO[5] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream.
10 Clock 6
Disable
R/W If 0, S_CLKO[6] is enabled.
When 1, S_CLKO[6] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream.
11 Clock 7
Disable
R/W If 0, S_CLKO[7] is enabled.
When 1, S_CLKO[7] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream.
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12 Clock 8
Disable
R/W If 0, S_CLKO[8] is enabled.
When 1, S_CLKO[8] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream.
13 Clock 9
Disable
R/W If 0, S_CLKO[9] is enabled.
When 1, S_CLKO[9] is disabled.
Upon secondary bus reset, this bit is initialized by shifting in a serial
data stream.
15-14 Reserved R/O Reserved
P_SERR# Status Register (Read/Write) – Offset 6Ah
Bit Function Type Description
0 Address Parity
error
R/WC Signal P_SERR# was asserted due to address parity error on either
side of the bridge. Reset to 0.
1Posted Write
Data Parity
error
R/WC Signal P_SERR# was asserted due to a posted write data parity
error on the target bus. Reset to 0.
2Post Write
nondelivery
R/WC Signal P_SERR# was asserted because PCI 6150 was unable to
deliver posted write data to the target before timeout counter
expires. Reset to 0.
3 Target abort
during posted
write
R/WC Signal P_SERR# was asserted because PCI 6150 received a
target abort when delivering posted write data. Reset to 0.
4 Master abort
during posted
write
R/WC Signal P_SERR# was asserted because PCI 6150 received a
master abort when delivering posted write data. Reset to 0.
5 Delayed write
nondelivery
R/WC Signal P_SERR# was asserted because PCI 6150 was unable to
deliver delayed write data before time-out counter expires. Reset to
0.
6 Delayed read
failed
R/WC Signal P_SERR# was asserted because PCI 6150 was unable to
read any data from the target before time-out counter expires.
Reset to 0.
7 Delayed
transaction
master
timeout
R/WC Signal P_SERR# was asserted because a master did not repeat a
read or write transaction before the master timeout counter expired
on the initiator’s bus. Reset to 0.
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ROR Control (R/W) – Offset 9Ch
Bit Function Type Description
6-0 Reserved R/O Reserved
7ROR Write
Enable
R/W Read Only Registers Write Enable: Subsystem Vender ID at Register
2Ch and Subsystem ID Register at 2Eh are normally Read Only.
Setting this bit to 1 will enable write to such Read Only ID Registers.
Power Management Registers DEh, E0h, and E3h are normally Read
Only. Setting this bit to 1 will enable write to all Read Only Power
Management Registers.
This bit must be cleared after the desired values have been modified in
the Read Only Registers.
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6.2.3 Hot Swap and Power Management Registers
Power Management Registers DEh, E0h, and E3h are normally Read Only. However their default value
can be changed by firmware or software by setting the Read Only Registers Write Enable bit at Register.
After any modifications to such registers, this Write Enable bit must be cleared to preserve their Read
Only nature.
Capability Identifier (R/O) – Offset DCh
This register is set to 01h to indicate power management interface registers.
Next Item Pointer (R/O) – Offset DDh
Set to E4h. This field provides an offset into the function's PCI Configuration Space pointing to the location of
next item in the function's capability list. In PCI 6150, this points to the hot swap registers.
Power Management Capabilities(R/O) – Offset DEh
This register is EEPROM or ROR Write controlled loadable, but is READ ONLY during normal operation.
Bit Function Type Description
0-2 Version R/O This register is set to 001b, indicating that this function complies with
Rev 1.0 of the PCI Power Management Interface Specification
3 PME Clock R/O This bit is a '0', indicating that PCI 6150 does not support PME#
signaling.
4 Auxiliary
Power Source
R/O This bit is set to ‘0’ since PCI 6150 does not support PME# signaling
5 DSI R/O Device Specific Initialization . Returns ‘0’ indicating that PCI 6150 does
not need special initialization
6-8 Reserved R/O Reserved
9 D1 Support R/O Returns ‘1’ indicating that PCI 6150 supports the D1 device power
state
10 D2 Support R/O Returns ‘1’ indicating that PCI 6150 supports the D2 device power
state
11-15 PME Support R/O Set to “0601” in Revision BA. Set to “7E01” in Revision BB.
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Power Management Control/ Status(R/W) – Offset E0h
This register is EEPROM or ROR Write controlled loadable, but is READ ONLY during normal operation.
Bit Function Type Description
0-1 Power State R/W This 2-bit field is used both to determine the current power state of a
function and to set the function into a new power state. The definition of
the field values is given below.
00b - D0
01b - D1
10b - D2
11b – D3hot
2-7 Reserved R/O Reserved
8 PME Enable R/W This bit is set to ‘0’ since PCI 6150 does not support PME# signaling
9-12 Data Select R/O This field returns ‘0000b’ indicating PCI 6150 does not return any
dynamic data
13-14 Data Scale R/O Returns ‘00b’ when read. PCI 6150 does not return any dynamic data.
15 PME Status R/W This bit is set to ‘0’ since PCI 6150 does not support PME# signaling
PMCSR Bridge Support(R/W) – Offset E2h
Bit Function Type Description
0-5 Reserved R/O Reserved
6 B2/B3 Support
for D3hot
R/O This bit reflects the state of the BPCC input pin. A ‘1’ indicates that
when PCI 6150 is programmed to D3hot state the secondary bus’s
clock is stopped.
7Bus Power
Control
Enable
R/O This bit reflects the state of the BPCC input pin. A ‘1’ indicates that the
power management state of the secondary bus follows that of PCI 6150
with one exception , D3hot state.
Power Management Data Register (RO) – Offset E3h
This register is EEPROM or ROR Write controlled loadable, but is READ ONLY during normal operation.
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Capability Identifier (R/O) – Offset E4h
This register is set to 06h to indicate Hot Swap interface registers.
Next Item Pointer (R/O) - Offset E5h
Set to E8h. This field provides an offset into the function's PCI Configuration Space pointing to the location of
next item in the function's capability list. In PCI 6150, this points to the Vital Product Data (VPD) registers.
Hot Swap Register(R/W) – Offset E6h
Bit Function Type Description
0 DHA R/W Device Hiding Arm. Reset to 0.
1 = Arm Device Hiding
0 = Disarm Device Hiding
DHA is set to 1 by hardware during hot swap port PCI RSTIN# going
inactive and handle switch is still unlocked. The locking of the handle
will clear this bit.
1EIM
ENUM# Mask
Status
R/W Enables or disables ENUM# assertion. Reset to 0.
0 = enable ENUM# signal
1 = mask off ENUM# signal
2 PIE R/O Pending INSert or EXTract: This bit is set when either INS or EXT is
“1” or INS is armed (Write 1 to EXT bit).
1 = either an insertion or an extraction is in progress.
0 = Neither is pending
3LOO
LED status
R/W Indicates if LED is on or off. Reset to 0.
0 = LED is off
1 = LED is on
5-4 PI R/W Programming Interface:
Hardcode at 01: INS, EST, LOO, EIM and PIE, Device Hiding are
supported.
6 EXT
Extraction
State
R/W1C This bit is set by hardware when the ejector handle is unlocked and
INS = 0.
7INS
Insertion State
R/W1C This bit is set by hardware when hot swap port RSTIN# is
deasserted, EEPROM autoload is completed and the ejector handle
is locked.
Writing 1 to EXT bit also arms INS.
15:8 Reserved R/O Reserved and a read returns all 0. Write has no effect.
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6.2.4 VPD Registers
Capability Identifier (R/O) - Offset E8h
This register is set to 03h to indicate VPD registers.
Next Item Pointer (R/O) - Offset E9h
Set to 00h.
VPD Register (R/W) – Offset EAh
Bit Function Type Description
1-0 Reserved R/O Reserved
7-2 VPD Address R/W VPD operation: Writing a ‘0’ to this bit generates a read cycle from the
EEPROM at the VPD address specified in bits 7-2 of this register. This
bit will remain at a logic ‘0’ value until EEPROM cycle is finished, then it
be set to ‘1’. Data for reads is available at register ECh
Writing a ‘1’ to this bit generates a write cycle to the EEPROM at the
VPD address specified in bits 7-2 of this register. This bit will remain at
a logic ‘1’ value until EEPROM cycle is finished, then it be cleared to ‘0’.
14-8 Reserved R/O Reserved
15 VPD
Operation
R/W VPD operation: Writing a ‘0’ to this bit generates a read cycle from the
EEPROM at the VPD address specified in bits 7-2 of this register. This
bit will remain at a logic ‘0’ value until EEPROM cycle is finished, then it
be set to ‘1’. Data for reads is available at register ECh
Writing a ‘1’ to this bit generates a write cycle to the EEPROM at the
VPD address specified in bits 7-2 of this register. This bit will remain at
a logic ‘1’ value until EEPROM cycle is finished, then it be cleared to ‘0’.
VPD Data Register (R/W) – Offset ECh
Bit Function Type Description
31-0 VPD Data R/W VPD Data (EEPROM data[addr + 0x40]) - The least significant byte of
this register corresponds to the byte of VPD at the address specified by
the VPD Address register. The data read from or written to this register
uses the normal PCI byte transfer capabilities.
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7 PCI Bus Operation
This chapter presents detailed information about PCI transactions PCI 6150 responds to and PCI transactions
initiated by PCI 6150.
7.1 PCI Transactions
Table 7–1 lists the command code and name of each PCI transaction that PCI 6150 initiates and responds to.
The Master and Target columns indicate support for each transaction when PCI 6150 initiates transactions as a
master, on the primary bus and on the secondary bus, and when PCI 6150 responds to transactions as a target,
on the primary bus and on the secondary bus.
Table 7–1, PCI Transactions
Initiates as Master Responds as Target Type of transaction
Primary Secondary Primary Secondary
0000 Interrupt acknowledge N N N N
0001 Special cycle Y Y N N
0010 I/O read Y Y Y Y
0011 I/O write Y Y Y Y
0100 Reserved N N N N
0101 Reserved N N N N
0110 Memory read Y Y Y Y
0111 Memory write Y Y Y Y
1000 Reserved N N N N
1001 Reserved N N N N
1010 Configuration read N Y Y N
1011 Configuration write Type-1 Y Y Type-1
1100 Memory read multiple Y Y Y Y
1101 Dual address cycle Y Y Y Y
1110 Memory read line Y Y Y Y
1111 Memory write and invalidate Y Y Y Y
As indicated in Table 7–1, the following PCI commands are not supported by PCI 6150:
• PCI 6150 ignores reserved command codes and does not generate any reserved commands.
• PCI 6150 never initiates an interrupt acknowledge transaction and, as a target, ignores interrupt acknowledge
transactions. Interrupt acknowledge transactions are expected to reside entirely on the primary PCI bus
closest to the host bridge.
• PCI 6150 does not respond to special cycle transactions. To generate special cycle transactions on other PCI
buses, either upstream or downstream, a Type-1 configuration command must be used.
• PCI 6150 does not generate Type-0 configuration transactions on the primary interface.
7.2 Single Address Phase
A 32-bit address uses a single address phase. This address is driven on AD[31:0], and the bus command is
driven on P_CBE[3:0]
PCI 6150 supports the linear increment address mode only, which is indicated when the low 2 address bits are
equal to 0. If either of the low 2 address bits is nonzero, PCI 6150 automatically disconnects the transaction after
the first data transfer.
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7.3 Dual Address Phase
PCI 6150 supports the Dual Address Cycle (DAC) bus command to transfer 64-bit addresses. In DAC
transactions, the first address phase is during the initial assertion of frame, and the second address phase is one
clock later. During the first address phase, the DAC command is presented on CBE[3:0], the lower 32 bits of the
address on AD[31:0]. The second address phase has the cycle command on CBE[3:0], and the upper 32 bits of
the address on AD[31:0].
DACs are used to access locations that are not in the first 4GB of PCI memory space. Addresses in the first 4GB
of memory space always use a Single Address Cycle (SAC).
PCI 6150 supports DAC in the upstream and downstream direction.
PCI 6150 responds to DAC for the following commands only:
• Memory Write
• Memory Write and Invalidate
• Memory Read
• Memory Read Line
• Memory Read Multiple
7.4 Device Select (DEVSEL#) Generation
PCI 6150 always performs positive address decoding when accepting transactions on either the primary or
secondary buses. PCI 6150 never subtractively decodes. Medium DEVSEL# timing is used for 33MHz operation
and Slow DEVSEL# timing is used for 66MHz operation.
7.5 Data Phase
Depending on the command type, PCI 6150 can support multiple data phase PCI transactions. Write transactions
are treated as either posted write or delayed write transactions.
Table 7–2 shows the method of forwarding used for each type of write operation.
Table 7–2, Write Transaction Forwarding
Type of Transaction Type of Forwarding
Memory write Posted
Memory write and invalidate Posted
I/O write Delayed
Type-1 configuration write Delayed
7.5.1 Posted Write Transactions
When PCI 6150 determines that a memory write transaction is to be forwarded across the bridge, PCI 6150
asserts DEVSEL# with slow timing and TRDY# in the same cycle, provided that enough buffer space is available
in the posted write data queue, and there are less than 4 outstanding posted transactions in the queue. PCI 6150
can accept 1 QUAD/DWORD of write data every PCI clock cycle; that is, no target wait states are inserted. Up to
256 bytes of posted write data is stored in internal posted write buffers and is eventually delivered to the target.
PCI 6150 continues to accept write data until one of the following events occurs:
• The initiator terminates the transaction normally.
• A cache line boundary or an aligned 4KB boundary is reached, depending on the transaction type.
• The posted write data buffer fills
When one of the last two events occurs, PCI 6150 returns a target disconnect to the requesting initiator on this
data phase to terminate the transaction.
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Once the posted write transaction is selected for completion, PCI 6150 requests ownership of the target bus. This
can occur while PCI 6150 is still receiving data on the initiator bus. Once PCI 6150 has ownership of the target
bus, and the target bus is detected in the idle condition, PCI 6150 generates the write cycle and continues to
transfer write data until all write data corresponding to that transaction is delivered, or until a target termination is
received. As long as write data exists in the queue, PCI 6150 can drive 1 QUAD/DWORD of write data each PCI
clock cycle. If write data is flowing through PCI 6150 and the initiator stalls, PCI 6150 will insert wait states on the
target bus if the queue empties.
PCI 6150 ends the transaction on the target bus when one of the following conditions is met:
• All posted write data has been delivered to the target.
• The target returns a target disconnect or target retry (PCI 6150 starts another transaction to deliver the rest of
the write data).
• The target returns a target abort (PCI 6150 discards remaining write data).
The master latency timer expires, and PCI 6150 no longer has the target bus grant (PCI 6150 starts another
transaction to deliver the remaining write data).
7.5.2 Memory Write and Invalidate Transactions
Memory Write and Invalidate transactions guarantee transfer of entire cache lines. By default, PCI 6150 will retry
a Memory Write and Invalidate cycle until there is space for at least 1 cache line of data in the internal buffers. It
will then complete the transaction on the secondary bus as a Memory Write and Invalidate cycle. PCI 6150 can
also be programmed to accept Memory Write and Invalidate cycles under the same conditions as normal memory
writes. In this case, if the write buffer fills before an entire cache line is transferred, PCI 6150 will disconnect and
complete the write cycle on the secondary bus as a normal Memory Write cycle. (Register 46, bit12). PCI 6150
disconnects Memory Write and Invalidate commands at aligned cache line boundaries. The cache line size value
in the cache line size register gives the number of DWORDs in a cache line. For PCI 6150, to generate Memory
Write and Invalidate transactions, this cache line size value must be written to a value that is 8h, 10h, or 20h. If an
invalid cache line size is programmed, wherein the value is 0, or is not a power of 2, or is greater than 20h
DWORDs, PCI 6150 sets the cache line size to the minimum value of 8h. PCI 6150 always disconnects on the
cache line boundary.
When the Memory Write and Invalidate transaction is disconnected before a cache line boundary is reached,
typically because the posted write data buffer fills, the transaction is converted to a Memory Write transaction.
7.5.3 Delayed Write Transactions
A Delayed Write transaction is used to forward I/O Write and Type-1 configuration cycles through PCI 6150, and
is limited to a single QUAD/DWORD data transfer.
When a write transaction is first detected on the initiator bus, PCI 6150 claims the access and returns a target
retry to the initiator. During the cycle, PCI 6150 samples the bus command, address, and address parity bits. PCI
6150 also samples the first data QUAD/DWORD, byte enable bits, and data parity. Cycle information is placed
into the delayed transaction queue if there are no other existing delayed transactions with the same cycle
information, and if the delayed transaction queue is not full. When PCI 6150 schedules delayed write transaction
to be the next cycle to be completed based on its ordering constraints, PCI 6150 initiates the transaction on the
target bus. PCI 6150 transfers the write data to the target.
If PCI 6150 receives a target retry in response to the write transaction on the target bus, it continues to repeat the
write transaction until the data transfer is completed, or until an error condition is encountered. If PCI 6150 is
unable to deliver write data after 224 attempts (programmable through register 45, bits 3-0), PCI 6150 ceases
further write attempts and returns a target abort to the initiator. The delayed transaction is removed from the
delayed transaction queue. PCI 6150 also asserts P_SERR# if the primary SERR# enable bit is set in the
command register. When the initiator repeats the same write transaction (same command, address, byte enable
bits, and data), after PCI 6150 has completed data delivery, and has all the complete cycle information in the
queue, PCI 6150 claims the access returns TRDY# to the initiator, to indicate that the write data was transferred.
If the initiator requests multiple QUAD/DWORD, PCI 6150 asserts STOP# in conjunction with TRDY# to signal a
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target disconnect. Note that only those bytes of write data with valid byte enable bits are compared. If any of the
byte enable bits are turned off (driven HIGH), the corresponding byte of write data is not compared.
If the initiator repeats the write transaction before the data has been transferred to the target, PCI 6150 returns a
target retry to the initiator. PCI 6150 continues to return a target retry to the initiator until write data is delivered to
the target or an error condition is encountered. When the write transaction is repeated, PCI 6150 does not make a
new entry into the delayed transaction queue.
PCI 6150 implements a discard timer that starts counting when the delayed write completion is at the head of the
delayed transaction queue. The initial value of this timer can be set to one of four values, selectable through both
the primary and the secondary master timeout bits in the bridge control register as well as the master timeout
divider bits in register 45h. If the discard timer expires before the write cycle is retried, PCI 6150 discards the
delayed write transaction from the delayed transaction queue. PCI 6150 also conditionally asserts P_SERR#.
7.5.4 Write Transaction Address Boundaries
PCI 6150 imposes internal address boundaries when accepting write data. The aligned address boundaries are
used to prevent PCI 6150 from continuing a transaction over a device address boundary and to provide an upper
limit on maximum latency. PCI 6150 returns a target disconnects to the initiator when it reaches the aligned
address boundaries under the conditions shown in Table 7–3.
Table 7–3, Write Transaction Disconnect Address Boundaries
Type of Transaction Condition Aligned Address Boundary
Delayed write All Disconnects after one data
transfer
Posted memory write Memory write disconnect
control bit = 01
4KB aligned address
boundary
Posted memory write Memory write disconnect
control bit = 11
Disconnects at cache line
boundary
Posted memory write
and invalidate Cache line size = 8,
8h-DWORD aligned address
boundary
Posted memory write
and invalidate
Cache line size = 10h 10h-DWORD aligned
address boundary
Posted memory write
and invalidate
Cache line size = 20h 20h-DWORD aligned
address boundary
1- Memory Write disconnect control bit is located in the chip control register at offset 40h in configuration space.
7.5.5 Buffering Multiple Write Transactions
PCI 6150 continues to accept posted memory write transactions as long as space for at least 1 DWORD of data
in the posted write data buffer remains and there are less than 4 outstanding posted memory write cycles. If the
posted write data buffer fills before the initiator terminates the write transaction, PCI 6150 returns a target
disconnect to the initiator.
Delayed write transactions are posted as long as at least one open entry in the delayed transaction queue exists.
PCI 6150 can queue up to four posted write transactions and four delayed transactions in both upstream and
downstream directions.
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7.5.6 Read Transactions
Delayed read forwarding is used for all read transactions crossing PCI 6150.
Delayed read transactions are treated as either prefetchable or nonprefetchable.
Table 7–4 shows the read behavior, prefetchable or nonprefetchable, for each type of read operation.
Table 7–4: Read Transaction Prefetching
Type of transaction Read behavior
I/O read Prefetching never done
Configuration read Prefetching never done
Memory read Downstream: prefetching used if address in prefetchable space
Upstream: prefetching used if prefetch disable is off (default)
Memory read line Prefetching always used if request is for more than one data transfer.
Memory read multiple Prefetching always used if request is for more than one data transfer.
7.5.7 Prefetchable Read Transactions
A prefetchable read transaction is a read transaction where PCI 6150 performs speculative DWORD reads,
transferring data from the target before it is requested from the initiator. This behavior allows a prefetchable read
transaction to consist of multiple data transfers. Only the first byte enable bits can be forwarded. PCI 6150 forces
all byte enable bits of subsequent transfers to be enabled.
Prefetchable behavior is used for memory read line and memory read multiple transactions, as well as for
memory read transactions that fall into prefetchable memory space.
The amount of the prefetched data depends on the type of transaction. The amount of prefetching may also be
affected by the amount of free buffer space available in PCI 6150, and by any read address boundaries
encountered. In addition, there are several PCI 6150-specific registers that can be used to optimize read prefetch
behavior.
Prefetching should not be used for those read transactions that have side effects in the target device, that is,
control and status registers, FIFOs, and so on. The target device’s base address register or registers indicate if a
memory address region is prefetchable.
7.5.8 Nonprefetchable Read Transactions
A nonprefetchable read transaction is read transaction by the initiator into a nonprefetchable region, and is used
for I/O and configuration read transactions, as well as for memory reads from nonprefetchable memory space. In
this case, PCI 6150 requests 1 and only 1 DWORD from the target and disconnects the initiator after delivery of
the first DWORD of read data.
Nonprefetchable read transactions should not be used for regions where extra read transactions could have side
effects, such as FIFO memory, or control registers. Accordingly, if it is important to retain the value of the byte
enable bits during the data phase, use nonprefetchable read transactions. If these locations are mapped in
memory space, use the memory read command and map the target into nonprefetchable (memory-mapped I/O)
memory space to utilize nonprefetching behavior.
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7.5.9 Read Prefetch Address Boundaries
PCI 6150 imposes internal read address boundaries on read prefetching. The address boundary is used by PCI
6150 to calculate the initial amount of data that it will prefetch. During read transactions to prefetchable regions,
PCI 6150 will prefetch data until it reaches one of these aligned address boundaries, unless the target signals a
target disconnect before the read prefetch boundary is reached. Once the aligned address boundary is reached,
PCI 6150 may optionally continue prefetching data, depending on certain conditions (see section on flow-through
optimization). When PCI 6150 finishes transferring this read data to the initiator, it returns a target disconnect with
the last data transfer, unless the initiator completes the transaction before all prefetched read data is delivered.
Any leftover prefetched data is discarded.
Prefetchable read transactions in flow-through mode prefetch to the nearest aligned 4KB address boundary, or
until the initiator deasserts FRAME#.
Table 7–5 shows the read prefetch address boundaries for read transactions during non-flow-through mode.
Table 7–5: Read Prefetch Address Boundaries
Type of transaction Address space Prefetch aligned address boundary
Configuration read - 1 DWORD (no prefetch)
I/O read - 1 DWORD (no prefetch)
Memory read Nonprefetchable 1 DWORD (no prefetch)
Memory read Prefetchable Configured through prefetch count registers
Memory read line Prefetchable Configured through prefetch count registers
Memory read multiple Prefetchable Configured through prefetch count registers
7.5.10 Delayed Read Requests
PCI 6150 treats all read transactions as delayed read transactions, which means that the read request from the
initiator is posted into a delayed transaction queue. Read data from the target is placed in the read data queue
directed toward the initiator bus interface and is transferred to the initiator when the initiator repeats the read
transaction.
When PCI 6150 accepts a delayed read request, it first samples the read address, read bus command, and
address parity. When IRDY# is asserted, PCI 6150 then samples the byte enable bits for the first data phase. This
information is entered into the delayed transaction queue. PCI 6150 terminates the transaction by signaling a
target retry to the initiator. Upon reception of the target retry, the initiator is required to continue to repeat the
same read transaction until at least one data transfer is completed, or until a target response other than a target
retry (target abort, or master abort) is received.
7.5.11 Delayed Read Completion with Target
When a delayed read request is scheduled by PCI 6150 to be executed, PCI 6150 arbitrates for the target bus
and initiates the read transaction, using the exact read address and read command captured from the initiator
during the initial delayed read request. If the read transaction is a nonprefetchable read, PCI 6150 drives the
captured byte enable bits during the next cycle. If the transaction is a prefetchable read transaction, it drives the
captured first byte enable bits followed by 0 for the subsequent data phases. If PCI 6150 receives a target retry in
response to the read transaction on the target bus, it continues to repeat the read transaction until at least one
data transfer is completed, or until an error condition is encountered. If the transaction is terminated via normal
master termination or target disconnect after at least one data transfer has been completed, PCI 6150 does not
initiate any further attempts to read more data.
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If PCI 6150 is unable to obtain read data from the target after 224 attempts (default), PCI 6150 ceases further read
attempts and returns a target abort to the initiator. The delayed transaction is removed from the delayed
transaction queue. PCI 6150 also asserts P_SERR# if the primary SERR# enable bit is set in the command
register.
Once PCI 6150 receives DEVSEL# and TRDY# from the target, it transfers the data stored in the internal read
FIFO, before terminating the transaction. PCI 6150 can accept 1 DWORD/QWORD of read data each PCI clock
cycle; no master wait states are inserted. The number of DWORD/QWORD transferred during a delayed read
transaction depends on the conditions given in Table 7–5 (assuming no disconnect is received from the target).
7.5.12 Delayed Read Completion on Initiator Bus
When the transaction has been completed on the target bus, and the delayed read data is at the head of the read
data queue, and all ordering constraints with posted write transactions have been satisfied, PCI 6150 transfers
the data to the initiator when the initiator repeats the transaction. For memory read transactions, PCI 6150 aliases
the memory read, memory read line, and memory read multiple bus commands when matching the bus command
of the transaction to the bus command in the delayed transaction queue. PCI 6150 returns a target disconnect
along with the transfer of the last DWORD of read data to the initiator. If PCI 6150 initiator terminates the
transaction before all read data has been transferred, the remaining read data left in data buffers is discarded.
When the master repeats the transaction and starts transferring prefetchable read data from data buffers while
the read transaction on the target bus is still in progress and before a read boundary is reached on the target bus,
the read transaction starts operating in flow-through mode. Because data is flowing through the data buffers from
the target to the initiator, long read bursts can then be sustained. In this case, the read transaction is allowed to
continue until the initiator terminates the transaction, or until an aligned 4KB address boundary is reached, or until
the buffer fills, whichever comes first. When the buffer empties, PCI 6150 reflects the stalled condition to the
initiator by deasserting TRDY# for a maximum of 8 clock periods until more read data is available; otherwise, PCI
6150 will disconnect the cycle. When the initiator terminates the transaction, PCI 6150 deassertion of FRAME# on
the initiator bus is forwarded to the target bus. Any remaining read data is discarded.
PCI 6150 implements a discard timer that starts counting when the delayed read completion is at the head of the
delayed transaction queue, and the read data is at the head of the read data queue. The initial value of this timer
is programmable through configuration register. If the initiator does not repeat the read transaction before Discard
Timer expires, PCI 6150 discards the read transaction (and the read data from its queues). PCI 6150 also
conditionally asserts P_SERR#.
PCI 6150 has the capability to post multiple delayed read requests, up to a maximum of four in each direction. If
an initiator starts a read transaction that matches the address and read command of a read transaction that is
already queued, the current read command is not stored as it is already contained in the delayed transaction
queue.
7.5.13 Configuration Transactions
Configuration transactions are used to initialize a PCI system. Every PCI device has a configuration space that is
accessed by configuration commands. All registers are accessible in configuration space only.
In addition to accepting configuration transactions for initialization of its own configuration space, PCI 6150
forwards configuration transactions for device initialization in hierarchical PCI systems, as well as for special cycle
generation.
To support hierarchical PCI bus systems, Type-0 and Type-1 configuration transactions are specified.
Type-0 configuration transactions are issued when the intended target resides on the same PCI bus as the
initiator. A Type-0 configuration transaction is identified by the configuration command and the Lowest 2 bits of
the address set to 00b.
Type-1 configuration transactions are issued when the intended target resides on another PCI bus, or when a
special cycle is to be generated on another PCI bus. A Type-1 configuration command is identified by the
configuration command and the Lowest 2 address bits set to 01b.
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The register number is found in both Type-0 and Type-1 formats and gives the DWORD address of the
configuration register to be accessed. The function number is also included in both Type-0 and Type-1 formats
and indicates which function of a multifunction device is to be accessed. For single-function devices, this value is
not decoded. Type-1 configuration transaction addresses also include a 5-bit field designating the device number
that identifies the device on the target PCI bus that is to be accessed. In addition, the bus number in Type-1
transactions specifies the PCI bus to which the transaction is targeted.
7.5.14 Type-0 Access to PCI 6150
The configuration space is accessed by a Type-0 configuration transaction on the primary interface. The
configuration space cannot be accessed from the secondary bus. PCI 6150 responds to a Type-0 configuration
transaction by asserting P_DEVSEL# when the following conditions are met during the address phase:
• The bus command is a configuration read transaction or configuration write transaction.
• Low 2 address bits P_AD[1:0] must be 00b.
• Signal P_IDSEL must be asserted.
PCI 6150 limits all configuration accesses to a single DWORD data transfer and returns a target disconnect with
the first data transfer if additional data phases are requested. Because read transactions to configuration space
do not have side effects, all bytes in the requested DWORD are returned, regardless of the value of the byte
enable bits.
Type-0 configuration write and read transactions do not use data buffers; that is, these transactions are
completed immediately, regardless of the state of the data buffers.
PCI 6150 ignores all Type-0 transactions initiated on the secondary interface.
7.5.15 Type-1 to Type-0 Translation
Type-1 configuration transactions are used specifically for device configuration in a hierarchical PCI bus system.
A PCI-to-PCI bridge is the only type of device that should respond to a Type-1 configuration command. Type-1
configuration commands are used when the configuration access is intended for a PCI device that resides on a
PCI bus other than the one where the Type-1 transaction is generated.
PCI 6150 performs a Type-1 to Type-0 translation when the Type-1 transaction is generated on the primary bus
and is intended for a device attached directly to the secondary bus. PCI 6150 must convert the configuration
command to a Type-0 format so that the secondary bus device can respond to it. Type-1 to Type-0 translations
are performed only in the downstream direction; that is, PCI 6150 generates a Type-0 transaction only on the
secondary bus, and never on the primary bus.
PCI 6150 responds to a Type-1 configuration transaction and translates it into a Type-0 transaction on the
secondary bus when the following conditions are met during the address phase:
• The low 2 address bits on P_AD[1:0] are 01b.
• The bus number in address field P_AD[23:16] is equal to the value in the secondary bus number register in
configuration space.
• The bus command on P_CBE[3:0] is a configuration read or configuration write transaction.
When PCI 6150 translates the Type-1 transaction to a Type-0 transaction on the secondary interface, it performs
the following translations to the address:
• Sets the low 2 address bits on S_AD[1:0] to 00b.
• Decodes the device number and drives the bit pattern specified in Table 7–6 on S_AD[31:16] for the purpose
of asserting the device’s IDSEL signal.
• Sets S_AD[15:11] to 0.
• Leaves unchanged the function number and register number fields.
PCI 6150 asserts a unique address line based on the device number. These address lines may be used as
secondary bus IDSEL signals. The mapping of the address lines depends on the device number in the Type-1
address bits P_AD[15:11]. Table 8–6 presents the mapping that PCI 6150 uses.
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Table 7–6: Device Number to IDSEL S_AD Pin Mapping
Device Number P_AD[15:11] Secondary IDSEL S_AD[31:16] S_AD Bit
0 00000 0000 0000 0000 0001 16
1 00001 0000 0000 0000 0010 17
2 00010 0000 0000 0000 0100 18
3 00011 0000 0000 0000 1000 19
4 00100 0000 0000 0001 0000 20
5 00101 0000 0000 0010 0000 21
6 00110 0000 0000 0100 0000 22
7 00111 0000 0000 1000 0000 23
8 01000 0000 0001 0000 0000 24
9 01001 0000 0010 0000 0000 25
10 01010 0000 0100 0000 0000 26
11 01011 0000 1000 0000 0000 27
12 01100 0001 0000 0000 0000 28
13 01101 0010 0000 0000 0000 29
14 01110 0100 0000 0000 0000 30
15 01111 1000 0000 0000 0000 31
Special Cycle 1XXXX 0000 0000 0000 0000 None
PCI 6150 can assert up to 16 unique address lines to be used as IDSEL signals for up to 16 devices on the
secondary bus, for device numbers ranging from 0 through 15. Because of electrical loading constraints of the
PCI bus, more than 16 IDSEL signals should not be necessary. However, if device numbers greater than 15 are
desired, some external method of generating IDSEL lines must be used, and no upper address bits are then
asserted. The configuration transaction is still translated and passed from the primary bus to the secondary bus. If
no IDSEL pin is asserted to a secondary device, the transaction ends in a master abort.
PCI 6150 forwards Type-1 to Type-0 configuration read or write transactions as delayed transactions. Type-1 to
Type-0 configuration read or write transactions are limited to a single 32-bit data transfer. When Type-1 to Type-0
configurations cycles are forwarded, address stepping is used, valid address is driven on the bus before the
FRAME# is asserted. Type-0 configuration address stepping is programmable through register 46h, bits 6-4.
7.5.16 Type-1 to Type-1 Forwarding
Type-1 to Type-1 transaction forwarding provides a hierarchical configuration mechanism when two or more
levels of PCI-to-PCI bridges are used.
When PCI 6150 detects a Type-1 configuration transaction intended for a PCI bus downstream from the
secondary bus, PCI 6150 forwards the transaction unchanged to the secondary bus. Ultimately, this transaction is
translated to a Type-0 configuration command or to a special cycle transaction by a downstream PCI-to-PCI
bridge. Downstream Type-1 to Type-1 forwarding occurs when the following conditions are met during the
address phase:
• The low 2 address bits are equal to 01b.
• The bus number falls in the range defined by the lower limit (exclusive) in the secondary bus number register
and the upper limit (inclusive) in the subordinate bus number register.
• The bus command is a Configuration Read or Write transaction.
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PCI 6150 also supports Type-1 to Type-1 forwarding of configuration write transactions upstream to support
upstream special cycle generation. A Type-1 configuration command is forwarded upstream when the following
conditions are met:
• The low 2 address bits are equal to 01b.
• The bus number falls outside the range defined by the lower limit (inclusive) in the secondary bus number
register and the upper limit (inclusive) in the subordinate bus number register.
• The device number in address bits AD[15:11] is equal to 11111b.
• The function number in address bits AD[10:8] is equal to 111b.
• The bus command is a Configuration Write transaction.
PCI 6150 forwards Type-1 to Type-1 configuration write transactions as delayed transactions. Type-1 to Type-1
configuration write transactions are limited to a single data transfer.
7.5.17 Special Cycles
The Type-1 configuration mechanism is used to generate special cycle transactions in hierarchical PCI systems.
Special cycle transactions are ignored by acting as a target and are not forwarded across the bridge. Special
cycle transactions can be generated from Type-1 configuration write transactions in either the upstream or the
downstream direction.
PCI 6150 initiates a special cycle on the target bus when a Type-1 Configuration Write transaction is detected on
the initiating bus and the following conditions are met during the address phase:
• The low 2 address bits on AD[1:0] are equal to 01b.
• The device number in address bits AD[15:11] is equal to 11111b.
• The function number in address bits AD[10:8] is equal to 111b.
• The register number in address bits AD[7:2] is equal to 000000b.
• The bus number is equal to the value in the secondary bus number register in configuration space for
downstream forwarding or equal to the value in the primary bus number register in configuration space for
upstream forwarding.
• The bus command on CBE is a Configuration Write command.
When PCI 6150 initiates the transaction on the target interface, the bus command is changed from configuration
write to special cycle. The address and data are forwarded unchanged. Devices that use special cycles ignore the
address and decode only the bus command. The data phase contains the special cycle message. The transaction
is forwarded as a delayed transaction, but in this case the target response is not forwarded back (because special
cycles result in a master abort). Once the transaction is completed on the target bus, through detection of the
master abort condition, PCI 6150 responds with TRDY# to the next attempt of the configuration transaction from
the initiator. If more than one data transfer is requested, PCI 6150 responds with a target disconnect operation
during the first data phase.
7.6 Transaction Termination
This section describes how PCI 6150 returns transaction termination conditions back to the initiator.
The initiator can terminate transactions with one of the following types of termination:
• Normal termination: It occurs when the initiator deasserts FRAME# at the beginning of the last data phase,
and deasserts IRDY# at the end of the last data phase in conjunction with either TRDY# or STOP# assertion
from the target.
• Master abort: It occurs when no target response is detected. When the initiator does not detect a DEVSEL#
from the target within five clock cycles after asserting FRAME#, the initiator terminates the transaction with a
master abort. If FRAME# is still asserted, the initiator deasserts FRAME# on the next cycle, and then
deasserts IRDY# on the following cycle. IRDY# must be asserted in the same cycle in which FRAME#
deasserts. If FRAME# is already deasserted, IRDY# can be deasserted on the next clock cycle following
detection of the master abort condition.
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The target can terminate transactions with one of the following types of termination:
• Normal termination: TRDY# and DEVSEL# asserted in conjunction with FRAME# deasserted and IRDY#
asserted.
• Target retry: STOP# and DEVSEL# asserted without TRDY# during the first data phase. No data transfers
occur during the transaction. This transaction must be repeated.
• Target disconnect (with data transfer): STOP# and DEVSEL# asserted with TRDY#. Signals that this is the
last data transfer of the transaction.
• Target disconnect (without data transfer): STOP# and DEVSEL# asserted without TRDY# after previous data
transfers have been made. Indicates that no more data transfers will be made during this transaction.
• Target abort: STOP# asserted without DEVSEL# and without TRDY#. Indicates that the target will never be
able to complete this transaction. DEVSEL# must be asserted for at least one cycle during the transaction
before the target abort is signaled.
7.6.1 Master Termination Initiated by PCI 6150
PCI 6150, as an initiator, uses normal termination if DEVSEL# is returned by the target within five clock cycles of
PCI 6150’s assertion of FRAME# on the target bus. As an initiator, PCI 6150 terminates a transaction when the
following conditions are met:
• During a delayed write transaction, a single DWORD/QWORD is delivered.
• During a nonprefetchable read transaction, a single DWORD/QWORD is transferred from the target.
• During a prefetchable read transaction, a prefetch boundary is reached.
• For a posted write transaction, all write data for the transaction is transferred from data buffers to the target.
• For a burst transfer, with the exception of memory write and invalidate transactions, the master latency timer
expires and PCI 6150’s bus grant is deasserted.
• The target terminates the transaction with a retry, disconnect, or target abort.
If PCI 6150 is delivering posted write data when it terminates the transaction because the master latency timer
expires, it initiates another transaction to deliver the remaining write data. The address of the transaction is
updated to reflect the address of the current DWORD to be delivered.
If PCI 6150 is prefetching read data when it terminates the transaction because the master latency timer expires,
it does not repeat the transaction to obtain more data.
7.6.2 Master Abort Received by PCI 6150
If the initiator initiates a transaction on the target bus and does not detect DEVSEL# returned by the target within
five clock cycles of PCI 6150’s assertion of FRAME#, PCI 6150 terminates the transaction as specified through
the master abort mode bit of the bridge control register.
For delayed read and write transactions, PCI 6150 can either assert TRDY# and return FFFF_FFFFh for reads, or
return target abort. SERR# is also optionally asserted.
When a master abort is received in response to a posted write transaction, PCI 6150 discards the posted write
data and makes no more attempts to deliver the data. PCI 6150 sets the received master abort bit in the status
register when the master abort is received on the primary bus, or it sets the received master abort bit in the
secondary status register when the master abort is received on the secondary interface. When a master abort is
detected in response to a posted write transaction, and the master abort mode bit is set, PCI 6150 also asserts
P_SERR# if enabled by the SERR# enable bit in the command register and if not disabled by the device-specific
P_SERR# disable bit for master abort during posted write transactions (that is, master abort mode = 1; SERR#
enable bit = 1; and P_SERR# disable bit for master aborts = 0.
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7.6.3 Target Termination Received by PCI 6150
When PCI 6150 initiates a transaction on the target bus and the target responds with DEVSEL#, the target can
end the transaction with one of the following types of termination:
• Normal termination (upon deassertion of FRAME#)
• Target retry
• Target disconnect
• Target abort
PCI 6150 handles these terminations in different ways, depending on the type of transaction being performed.
7.6.3.1 Delayed Write Target Termination Response
When PCI 6150 initiates a delayed write transaction, the type of target termination received from the target can be
passed back to the initiator. Table 7–7 shows the response to each type of target termination that occurs during a
delayed write transaction.
PCI 6150 repeats a delayed write transaction until one of the following conditions is met:
• PCI 6150 completes at least one data transfer.
• PCI 6150 receives a master abort.
• PCI 6150 receives a target abort.
PCI 6150 makes 224 (default) write attempts resulting in a response of target retry.
Table 7–7: Response to Delayed Write Target Termination
Target Termination Response
Normal Return disconnect to initiator with first data transfer only if
multiple data phases requested.
Target retry Return target retry to initiator. Continue write attempts to target.
Target disconnect Return disconnect to initiator with first data transfer only if
multiple data phases requested.
Target abort Return target abort to initiator.
Set received target abort bit in target interface status register.
Set signaled target abort bit in initiator interface status register.
After PCI 6150 makes 224 attempts of the same delayed write transaction on the target bus, PCI 6150 asserts
P_SERR# if the primary SERR# enable bit is set in the command register and the implementation-specific
P_SERR# disable bit for this condition is not set in the P_SERR# event disable register. PCI 6150 stops initiating
transactions in response to that delayed write transaction. The delayed write request is discarded. Upon a
subsequent write transaction attempt by the initiator, PCI 6150 returns a target abort.
7.6.3.2 Posted Write Target Termination Response
When PCI 6150 initiates a posted write transaction, the target termination cannot be passed back to the initiator.
Table 7–8 shows the response to each type of target termination that occurs during a posted write transaction.
Table 7–8: Response to Posted Write Target Termination
Target termination Response
Normal No additional action.
Target retry Repeat write transaction to target.
Target disconnect Initiate write transaction to deliver remaining posted write data.
Target abort Set received target abort bit in the target interface status register.
Assert P_SERR# if enabled, and set the signaled system error bit in
primary status register.
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Note that when a target retry or target disconnect is returned and posted write data associated with that
transaction remains in the write buffers, PCI 6150 initiates another write transaction to attempt to deliver the rest
of the write data. In the case of a target retry, the exact same address will be driven as for the initial write
transaction attempt. If a target disconnect is received, the address that is driven on a subsequent write transaction
attempt is updated to reflect the address of the current DWORD. If the initial write transaction is a memory write
and invalidate transaction, and a partial delivery of write data to the target is performed before a target disconnect
is received, PCI 6150 uses the memory write command to deliver the rest of the write data because less than a
cache line will be transferred in the subsequent write transaction attempt.
After PCI 6150 makes 224 write transaction attempts and fails to deliver all the posted write data associated with
that transaction, PCI 6150 asserts P_SERR# if the primary SERR# enable bit is set in the command register and
the device-specific P_SERR# disable bit for this condition is not set in the P_SERR# event disable register. The
write data is discarded.
7.6.3.3 Delayed Read Target Termination Response
When PCI 6150 initiates a delayed read transaction, the abnormal target responses can be passed back to the
initiator. Other target responses depend on how much data the initiator requests. Table 7–9 shows the response
to each type of target termination that occurs during a delayed read transaction.
Table 7–9: Response to Delayed Read Target Termination
Target termination Response
Normal If prefetchable, target disconnect only if initiator requests more data than
read from target. If nonprefetchable, target disconnect on first data phase.
Target retry Reinitiate read transaction to target
Target disconnect If initiator requests more data than read from target, return target
disconnect to initiator
Target abort Return target abort to initiator.
Set received target abort bit in the target interface status register.
Set signaled target abort bit in the initiator interface status register.
PCI 6150 repeats a delayed read transaction until one of the following conditions is met:
• PCI 6150 completes at least one data transfer.
• PCI 6150 receives a master abort.
• PCI 6150 receives a target abort.
• PCI 6150 makes 224 read attempts resulting in a response of target retry.
After PCI 6150 makes 224 attempts of the same delayed read transaction on the target bus, PCI 6150 asserts
P_SERR# if the primary SERR# enable bit is set in the command register and the implementation-specific
P_SERR# disable bit for this condition is not set in the P_SERR# event disable register. PCI 6150 stops initiating
transactions in response to that delayed read transaction. The delayed read request is discarded. Upon a
subsequent read transaction attempt by the initiator, PCI 6150 returns a target abort.
7.6.4 Target Termination Initiated by PCI 6150
PCI 6150 can return a Target Retry, Target Disconnect, or Target-Abort to an initiator for reasons other than
detection of that condition at the target interface.
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7.6.4.1 Target Retry
PCI 6150 returns a Target Retry to the initiator when it cannot accept write data or return read data as a result of
internal conditions. PCI 6150 returns a target retry to an initiator when any of the following conditions is met:
For delayed write transactions:
• The transaction is being entered into the delayed transaction queue.
• The transaction has already been entered into the delayed transaction queue, but target response has
not yet been received.
• Target response has been received but the posted memory write ordering rule prevents the cycle from
being completed.
• The delayed transaction queue is full, and the transaction cannot be queued.
• A transaction with the same address and command has been queued.
• A locked sequence is being propagated across PCI 6150, and the write transaction is not a locked
transaction.
• The target bus is locked and the write transaction is a locked transaction.
For delayed read transactions:
• The transaction is being entered into the delayed transaction queue.
• The read request has already been queued, but read data is not yet available.
• Data has been read from the target, but it is not yet at the head of the read data queue, or a posted write
transaction precedes it.
• The delayed transaction queue is full, and the transaction cannot be queued.
• A delayed read request with the same address and bus command has already been queued.
• A locked sequence is being propagated across PCI 6150, and the read transaction is not a locked
transaction.
• The target bus is locked and the write transaction is a locked transaction.
For posted write transactions:
• The posted write data buffer does not have enough space for the address and at least two QWORDs of write
data.
• A locked sequence is being propagated across PCI 6150, and the write transaction is not a locked
transaction.
When a target retry is returned to the initiator of a delayed transaction, the initiator must repeat the transaction
with the same address and bus command as well as the data if this is a write transaction, within the time frame
specified by the master timeout value; otherwise, the transaction is discarded from the buffers.
7.6.4.2 Target Disconnected
PCI 6150 returns a Target Disconnect to an initiator when one of the following conditions is met:
• PCI 6150 hits an internal address boundary
• PCI 6150 cannot accept any more write data
• PCI 6150 has no more read data to deliver
7.6.4.3 Target-Abort
PCI 6150 returns a Target-Abort to an initiator when one of the following conditions is met:
• PCI 6150 is returning a target abort from the intended target.
• PCI 6150 detects a master abort on the target, and the master abort mode bit is set.
• PCI 6150 is unable to obtain delayed read data from the target or to deliver delayed write data to the
target after 224 attempts.
When PCI 6150 returns a target abort to the initiator, it sets the signaled target abort bit in the status register
corresponding to the initiator interface.
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8 Address Decoding
PCI 6150 uses three address ranges that control I/O and memory transaction forwarding. These address ranges
are defined by base and limit address registers in the configuration space. This chapter describes these address
ranges, as well as ISA-mode and VGA-addressing support.
8.1 Address Ranges
PCI 6150 uses the following address ranges that determine which I/O and memory transactions are forwarded
from the primary PCI bus to the secondary PCI bus, and from the secondary bus to the primary bus:
• One 32-bit I/O address range
• One 32-bit memory-mapped I/O (nonprefetchable memory) range
• One 32-bit prefetchable memory address range
Transactions falling within these ranges are forwarded downstream from the primary PCI bus to the secondary
PCI bus. Transactions falling outside these ranges are forwarded upstream from the secondary PCI bus to the
primary PCI bus.
8.2 I/O Address Decoding
PCI 6150 uses the following mechanisms that are defined in the configuration space to specify the I/O address
space for downstream and upstream forwarding:
• I/O base and limit address registers
• The ISA enable bit
• The VGA mode bit
• The VGA snoop bit
This section provides information on the I/O address registers and ISA mode.
To enable downstream forwarding of I/O transactions, the I/O enable bit must be set in the command register in
configuration space. If the I/O enable bit is not set, all I/O transactions initiated on the primary bus are ignored. To
enable upstream forwarding of I/O transactions, the master enable bit must be set in the command register. If the
master enable bit is not set, PCI 6150 ignores all I/O and memory transactions initiated on the secondary bus.
Setting the master enable bit also allows upstream forwarding of memory transactions.
Caution: If any configuration state affecting I/O transaction forwarding is changed by a configuration write
operation on the primary bus at the same time that I/O transactions are ongoing on the secondary bus, the PCI
6150 response to the secondary bus I/O transactions is not predictable. Configure the I/O base and limit address
registers, ISA enable bit, VGA mode bit, and VGA snoop bit before setting the I/O enable and master enable bits,
and change them subsequently only when the primary and secondary PCI buses are idle.
8.2.1 I/O Base and Limit Address Registers
PCI 6150 implements one set of I/O base and limit address registers in configuration space that define an I/O
address range downstream forwarding. PCI 6150 supports 32-bit I/O addressing, which Allows I/O addresses
downstream of PCI 6150 to be mapped anywhere in a 4GB I/O address space.
I/O transactions with addresses that fall inside the range defined by the I/O base and limit registers are forwarded
downstream from the primary PCI bus to the secondary PCI bus. I/O transactions with addresses that fall outside
this range are forwarded upstream from the secondary PCI bus to the primary PCI bus.
The I/O range can be turned off by setting the I/O base address to a value greater than that of the I/O limit
address. When the I/O range is turned off, all I/O transactions are forwarded upstream, and no I/O transactions
are forwarded downstream.
The I/O range has a minimum granularity of 4KB and is aligned on a 4KB boundary. The maximum I/O range is
4GB in size.
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The I/O base register consists of an 8-bit field at configuration address 1Ch, and a 16-bit field at address 30h. The
top 4 bits of the 8-bit field define bits [15:12] of the I/O base address. The bottom 4 bits read only as 1h to indicate
that PCI 6150 supports 32-bit I/O addressing. Bits [11:0] of the base address are assumed to be 0, which
naturally aligns the base address to a 4KB boundary. The 16 bits contained in the I/O base upper 16 bits register
at configuration offset 30h define AD[31:16] of the I/O base address. All 16 bits are read/write. After primary bus
reset or chip reset, the value of the I/O base address is initialized to 0000_0000h.
The I/O limit register consists of an 8-bit field at configuration offset 1Dh and a 16-bit field at offset 32h. The top 4
bits of the 8-bit field define bits [15:12] of the I/O limit address. The bottom 4 bits read only as 1h to indicate that
32-bit I/O addressing is supported. Bits [11:0] of the limit address are assumed to be FFFh, which naturally aligns
the limit address to the top of a 4KB I/O address block. The 16 bits contained in the I/O limit upper 16 bits register
at configuration offset 32h define AD[31:16] of the I/O limit address. All 16 bits are read/write. After primary bus
reset or chip reset, the value of the I/O limit address is reset to 0000 0FFFh.
Note
Write these registers with their appropriate values before setting either the I/O enable bit or the master enable bit
in the command register in configuration space.
8.3 ISA Mode
PCI 6150 supports ISA mode by providing an ISA enable bit in the bridge control register in configuration space.
ISA mode modifies the response of PCI 6150 inside the I/O address range in order to support mapping of I/O
space in the presence of an ISA bus in the system. This bit only affects the response of PCI 6150 when the
transaction falls inside the address range defined by the I/O base and limit address registers, and only when this
address also falls inside the first 64KB of I/O space (address bits [31:16] are 0000h).
When the ISA enable bit is set, PCI 6150 does not forward downstream any I/O transactions addressing the top
768 bytes of each aligned 1KB block. Only those transactions addressing the bottom 256 bytes of an aligned 1KB
block inside the base and limit I/O address range are forwarded downstream. Transactions above the 64KB I/O
address boundary are forwarded as defined by the address range defined by the I/O base and limit registers.
Accordingly, if the ISA enable bit is set, PCI 6150 forwards upstream those I/O transactions addressing the top
768 bytes of each aligned 1KB block within the first 64KB of I/O space. The master enable bit in the command
configuration register must also be set to enable upstream forwarding. All other I/O transactions initiated on the
secondary bus are forwarded upstream only if they fall outside the I/O address range.
When the ISA enable bit is set, devices downstream of PCI 6150 can have I/O space mapped into the first 256
bytes of each 1KB chunk below the 64KB boundary, or anywhere in I/O space above the 64KB boundary.
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8.4 Memory Address Decoding
PCI 6150 has three mechanisms for defining memory address ranges for forwarding of memory transactions:
• Memory-mapped I/O base and limit address registers
• Prefetchable memory base and limit address registers
• VGA mode
This section describes the first two mechanisms.
To enable downstream forwarding of memory transactions, the memory enable bit must be set in the command
register in configuration space. To enable upstream forwarding of memory transactions, the master enable bit
must be set in the command register. Setting the master enable bit also allows upstream forwarding of I/O
transactions.
Caution
If any configuration state affecting memory transaction forwarding is changed by a configuration write operation
on the primary bus at the same time that memory transactions are ongoing on the secondary bus, response to the
secondary bus memory transactions is not predictable. Configure the memory-mapped I/O base and limit address
registers, prefetchable memory base and limit address registers, and VGA mode bit before setting the memory
enable and master enable bits, and change them subsequently only when the primary and secondary PCI buses
are idle.
8.4.1 Memory-Mapped I/O Base and Limit Address Registers
Memory-mapped I/O is also referred to as nonprefetchable memory. The memory-mapped I/O base address and
memory-mapped I/O limit address registers define an address range that PCI 6150 uses to determine when to
forward memory commands. PCI 6150 forwards a memory transaction from the primary to the secondary
interface if the transaction address falls within the memory-mapped I/O address range. PCI 6150 ignores memory
transactions initiated on the secondary interface that fall into this address range. Any transactions that fall outside
this address range are ignored on the primary interface and are forwarded upstream from the secondary interface
(provided that they do not fall into the prefetchable memory range or are not forwarded downstream by the VGA
mechanism).
The memory-mapped I/O range supports 32-bit addressing only. The PCI-to-PCI Bridge Architecture Specification
does not provide for 64-bit addressing in the memory-mapped I/O space. The memory-mapped I/O address range
has a granularity and alignment of 1MB. The maximum memory-mapped I/O address range is 4GB.
The memory-mapped I/O address range is defined by a 16-bit memory-mapped I/O base address register at
configuration offset 20h and by a 16-bit memory-mapped I/O limit address register at offset 22h. The top 12 bits of
each of these registers correspond to bits [31:20] of the memory address. The low 4 bits are hardwired to 0. The
low 20 bits of the memory-mapped I/O base address are assumed to be 0 0000h, which results in a natural
alignment to a 1MB boundary. The low 20 bits of the memory-mapped I/O limit address are assumed to be F
FFFFh, which results in an alignment to the top of a 1MB block.
Note
Write these registers with their appropriate values before setting either the memory enable bit or the master enable bit in the
command register in configuration space.
To turn off the memory-mapped I/O address range, write the memory-mapped I/O base address register with a
value greater than that of the memory-mapped I/O limit address register.
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8.4.2 Prefetchable Memory Base and Limit Address Registers
Locations accessed in the prefetchable memory address range must have true memory-like behavior and must
not exhibit side effects when read. This means that extra reads to a prefetchable memory location must have no
side effects. PCI 6150 prefetches for all types of memory read commands in this address space.
PCI 6150 prefetchable memory base address and prefetchable memory limit address registers define an address
range that PCI 6150 uses to determine when to forward memory commands. PCI 6150 forwards a memory
transaction from the primary to the secondary interface if the transaction address falls within the prefetchable
memory address range. PCI 6150 ignores memory transactions initiated on the secondary interface that fall into
this address range. PCI 6150 does not respond to any transactions that fall outside this address range on the
primary interface and forwards those transactions upstream from the secondary interface (provided that they do
not fall into the memory-mapped I/O range or are not forwarded by the VGA mechanism).
PCI 6150 prefetchable memory range supports 64-bit addressing and provides additional registers to define the
upper 32 bits of the memory address range, PCI 6150 prefetchable memory base address upper 32 bits register,
and the prefetchable memory limit address upper 32 bits register. For address comparison, a single address cycle
(32-bit address) prefetchable memory transaction is treated like a 64-bit address transaction where the upper 32
bits of the address are equal to 0. This upper 32-bit value of 0 is compared to the prefetchable memory base
address upper 32 bits register and the prefetchable memory limit address upper 32 bits register. The prefetchable
memory base address upper 32 bits register must be 0 in order to pass any single address cycle transactions
downstream.
The prefetchable memory address range has a granularity and alignment of 1MB. The maximum memory address
range is 4GB when 32-bit addressing is used, and 264 bytes when 64-bit addressing is used.
The prefetchable memory address range is defined by a 16-bit prefetchable memory base address register at
configuration offset 24h and by a 16-bit prefetchable memory limit address register at offset 26h. The top 12 bits
of each of these registers correspond to bits [31:20] of the memory address. The low 4 bits are hardwired to 1h,
indicating 64-bit address support. The low 20 bits of the prefetchable memory base address are assumed to be 0
0000h, which results in a natural alignment to a 1MB boundary. The low 20 bits of the prefetchable memory limit
address are assumed to be F_FFFFh, which results in an alignment to the top of a 1MB block.
Note
Write these registers with their appropriate values before setting either the memory enable bit or the master enable bit in the
command register in configuration space.
To turn off the prefetchable memory address range, write the prefetchable memory base address register with a
value greater than that of the prefetchable memory limit address register. The entire base value must be greater
than the entire limit value, meaning that the upper 32 bits must be considered. Therefore, to disable the address
range, the upper 32 bits registers can both be set to the same value, while the lower base register is set greater
than the lower limit register; otherwise, the upper 32-bit base must be greater than the upper 32-bit limit.
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8.5 VGA Support
PCI 6150 provides two modes for VGA support:
• VGA mode, supporting VGA-compatible addressing
• VGA snoop mode, supporting VGA palette forwarding
8.5.1 VGA Mode
When a VGA-compatible device exists downstream from PCI 6150, set the VGA mode bit in the bridge control
register in configuration space to enable VGA mode. When PCI 6150 is operating in VGA mode, it forwards
downstream those transactions addressing the VGA frame buffer memory and VGA I/O registers, regardless of
the values of the base and limit address registers. PCI 6150 ignores transactions initiated on the secondary
interface addressing these locations.
The VGA frame buffer consists of the following memory address range: 000A_0000h – 000B_FFFFh
Read transactions to frame buffer memory are treated as nonprefetchable. PCI 6150 requests only a single data
transfer from the target, and read byte enable bits are forwarded to the target bus.
The VGA I/O addresses consist of the following I/O addresses:
• 3B0h–3BBh
• 3C0h–3DFh
These I/O addresses are aliased every 1KB throughout the first 64KB of I/O space. This means that address bits
[15:10] are not decoded and can be any value, while address bits [31:16] must be all 0s.
VGA BIOS addresses starting at C0000h are not decoded in VGA mode.
8.5.2 VGA Snoop Mode
PCI 6150 provides VGA snoop mode, Allowing for VGA palette write transactions to be forwarded downstream.
This mode is used when a graphics device downstream from PCI 6150 needs to snoop or respond to VGA palette
write transactions. To enable the mode, set the VGA snoop bit in the command register in configuration space.
Note that PCI 6150 claims VGA palette write transactions by asserting DEVSEL# in VGA snoop mode.
When the VGA snoop bit is set, PCI 6150 forwards downstream transactions with the following I/O addresses:
• 3C6h
• 3C8h
• 3C9h
Note that these addresses are also forwarded as part of the VGA compatibility mode previously described. Again,
address bits [15:10] are not decoded, while address bits [31:16] must be equal to 0, which means that these
addresses are aliased every 1KB throughout the first 64KB of I/O space.
Note
If both the VGA mode bit and the VGA snoop bit are set, PCI 6150 behaves in the same way as if only the VGA mode bit were
set.
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9 Transaction Ordering
To maintain data coherency and consistency, PCI 6150 complies with the ordering rules set forth in the PCI Local
Bus Specification, Revision 2.2.
9.1 Transaction Ordering
This section describes the ordering rules that control transaction forwarding across PCI 6150. For a more detailed
discussion of transaction ordering, see Appendix E of the PCI Local Bus Specification, Revision 2.2.
9.1.1 Transactions Governed by Ordering Rules
Ordering relationships are established for the following classes of transactions crossing PCI 6150:
• Posted write transactions, comprised of memory write and memory write and invalidate transactions
Posted write transactions complete at the source before they complete at the destination; that is, data is
written into intermediate data buffers before it reaches the target.
• Delayed write request transactions, comprised of I/O write and configuration write transactions
Delayed write requests are terminated by target retry on the initiator bus and are queued in the delayed
transaction queue. A delayed write transaction must complete on the target bus before it completes on the
initiator bus.
• Delayed write completion transactions, also comprised of I/O write and configuration write transactions.
Delayed write completion transactions have been completed on the target bus, and the target response is
queued in the buffers. A delayed write completion transaction proceeds in the direction opposite that of the
original delayed write request; that is, a delayed write completion transaction proceeds from the target bus to
the initiator bus.
• Delayed read request transactions, comprised of all memory read, I/O read, and configuration read
transactions.
Delayed read requests are terminated by target retry on the initiator bus and are queued in the delayed
transaction queue.
• Delayed read completion transactions, comprised of all memory read, I/O read, and configuration read
transactions.
Delayed read completion transactions have been completed on the target bus, and the read data has been
queued in the read data buffers. A delayed read completion transaction proceeds in the direction opposite
that of the original delayed read request; that is, a delayed read completion transaction proceeds from the
target’s bus to the initiator’s bus.
PCI 6150 does not combine or merge write transactions:
• PCI 6150 does not combine separate write transactions into a single write transaction—this optimization is
best implemented in the originating master.
• PCI 6150 does not merge bytes on separate masked write transactions to the same DWORD address—this
optimization is also best implemented in the originating master.
• PCI 6150 does not collapse sequential write transactions to the same address into a single write
transaction—the PCI Local Bus Specification does not permit this combining of transactions.
9.1.2 General Ordering Guidelines
Independent transactions on the primary and secondary buses have a relationship only when those transactions
cross PCI 6150.
The following general ordering guidelines govern transactions crossing PCI 6150:
• The ordering relationship of a transaction with respect to other transactions is determined when the
transaction completes, that is, when a transaction ends with a termination other than target retry.
• Requests terminated with target retry can be accepted and completed in any order with respect to other
transactions that have been terminated with target retry. If the order of completion of delayed requests is
important, the initiator should not start a second delayed transaction until the first one has been completed. If
more than one delayed transaction is initiated, the initiator should repeat all the delayed transaction requests,
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using some fairness algorithm. Repeating a delayed transaction cannot be contingent on completion of
another delayed transaction; otherwise, a deadlock can occur.
• Write transactions flowing in one direction have no ordering requirements with respect to write transactions
flowing in the other direction. PCI 6150 can accept posted write transactions on both interfaces at the same
time, as well as initiate posted write transactions on both interfaces at the same time.
• The acceptance of a posted memory write transaction as a target can never be contingent on the completion
of a non-locked, nonposted transaction as a master. This is true of PCI 6150 and must also be true of other
bus agents; otherwise, a deadlock can occur.
• PCI 6150 accepts posted write transactions, regardless of the state of completion of any delayed transactions
being forwarded across PCI 6150.
9.1.3 Ordering Rules
Table 9–1 shows the ordering relationships of all the transactions and refers by number to the ordering rules that
follow.
Table 9–1: Summary of Transaction Ordering
Pass Posted
Write
Delayed read
Request
Delayed Write
Request
Delayed Read
Completion
Delayed Write
Completion
Posted write N1 Y5 Y5 Y5 Y5
Delayed read
request
N2 Y Y Y Y
Delayed write
request
N4 Y Y Y Y
Delayed read
completion
N3 Y Y Y Y
Delayed write
completion
Y Y Y Y Y
Note
The superscript accompanying some of the table entries refers to any applicable ordering rule listed in this section. Many
entries are not governed by these ordering rules; therefore, the implementation can choose whether or not the transactions
pass each other.
The entries without superscripts reflect PCI 6150’s implementation choices.
The following ordering rules describe the transaction relationships. Each ordering rule is followed by an
explanation, and the ordering rules are referred to by number in Table 9–1. These ordering rules apply to posted
write transactions, delayed write and read requests, and delayed write and read completion transactions crossing
PCI 6150 in the same direction. Note that delayed completion transactions cross PCI 6150 in the direction
opposite that of the corresponding delayed requests.
1. Posted write transactions must complete on the target bus in the order in which they were received on the
initiator bus.
The subsequent posted write transaction can be setting a flag that covers the data in the first posted write
transaction; if the second transaction were to complete before the first transaction, a device checking the
flag could subsequently consume stale data.
2. A delayed read request traveling in the same direction as a previously queued posted write transaction
must push the posted write data ahead of it. The posted write transaction must complete on the target
bus before the delayed read request can be attempted on the target bus.
The read transaction can be to the same location as the write data, so if the read transaction were to pass
the write transaction, it would return stale data.
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3. A delayed read completion must ‘‘pull’’ ahead of previously queued posted write data traveling in the
same direction. In this case, the read data is traveling in the same direction as the write data, and the
initiator of the read transaction is on the same side of the as the target of the write transaction. The
posted write transaction must complete to the target before the read data is returned to the initiator.
The read transaction can be to a status register of the initiator of the posted write data and therefore
should not complete until the write transaction is complete.
4. Delayed write requests cannot pass previously queued posted write data. As in the case of posted
memory write transactions, the delayed write transaction can be setting a flag that covers the data in the
posted write transaction; if the delayed write request were to complete before the earlier posted write
transaction, a device checking the flag could subsequently consume stale data.
5. Posted write transactions must be given opportunities to pass delayed read and write requests and
completions. Otherwise, deadlocks may occur when bridges that support delayed transactions are used in
the same system with bridges that do not support delayed transactions. A fairness algorithm is used to
arbitrate between the posted write queue and the delayed transaction queue.
PCI 6150 can generate cycles across the bridge in the same order than requested if bit 2 of register 46h is set.
By default, requested cycles can execute out of order across the bridge, if all other ordering rules are satisfied.
So, if PCI 6150 starts a delayed transaction that is retried by the target, it can execute another transaction in the
delayed transaction request queue. Also, if there is both delayed read and delayed write requests in the queue,
and the read data FIFOs are full, PCI 6150 may execute the delayed write request before the delayed read
request.
On cycle completion, PCI 6150 may complete cycles in a different order than requested by the initiator.
9.1.4 Data Synchronization
Data synchronization refers to the relationship between interrupt signaling and data delivery. The PCI Local Bus
Specification, Revision 2.2, provides the following alternative methods for synchronizing data and interrupts:
• The device signaling the interrupt performs a read of the data just written (software).
• The device driver performs a read operation to any register in the interrupting device before accessing data
written by the device (software).
• System hardware guarantees that write buffers are flushed before interrupts are forwarded.
PCI 6150 does not have a hardware mechanism to guarantee data synchronization for posted write transactions.
Therefore, all posted write transactions must be followed by a read operation, either from the device to the
location just written (or some other location along the same path), or from the device driver to one of the device
registers.
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10 Error Handling
PCI 6150 checks, forwards, and generates parity on both the primary and secondary interfaces. To maintain
transparency, PCI 6150 always tries to forward the existing parity condition on one bus to the other bus, along
with address and data. PCI 6150 always attempts to be transparent when reporting errors, but this is not always
possible, given the presence of posted data and delayed transactions.
To support error reporting on the PCI bus, PCI 6150 implements the following:
• PERR# and SERR# signals on both the primary and secondary interfaces
• Primary status and secondary status registers
• The device-specific P_SERR# event disable register
• The device-specific P_SERR# status register
This chapter provides detailed information about how PCI 6150 handles errors. It also describes error status
reporting and error operation disabling.
10.1 Address Parity Errors
PCI 6150 checks address parity for all transactions on both buses, for all address and all bus commands.
When PCI 6150 detects an address parity error on the primary interface, the following events occur:
• If the parity error response bit is set in the command register, PCI 6150 does not claim the transaction with
P_DEVSEL#; this may allow the transaction to terminate in a Master-Abort. If the parity error response bit is
not set, PCI 6150 proceeds normally and accepts the transaction if it is directed to or across PCI 6150.
• PCI 6150 sets the detected parity error bit in the status register.
• PCI 6150 asserts P_SERR# and sets the signaled system error bit in the status register, if both of the
following conditions are met:
♦ The SERR# enable bit is set in the command register.
♦ The parity error response bit is set in the command register.
When PCI 6150 detects an address parity error on the secondary interface, the following events occur:
• If the parity error response bit is set in the bridge control register, PCI 6150 does not claim the transaction
with S_DEVSEL#; this may allow the transaction to terminate in a master abort. If the parity error response bit
is not set, PCI 6150 proceeds normally and accepts the transaction if it is directed to or across PCI 6150.
• PCI 6150 sets the detected parity error bit in the secondary status register.
• PCI 6150 asserts P_SERR# and sets the signaled system error bit in the status register, if both of the
following conditions are met:
♦ The SERR# enable bit is set in the command register.
♦ The parity error response bit is set in the bridge control register.
10.2 Data Parity Errors
When forwarding transactions, PCI 6150 attempts to pass the data parity condition from one interface to the other
unchanged, whenever possible, to Allow the master and target devices to handle the error condition.
The following sections describe, for each type of transaction, the sequence of events that occurs when a parity
error is detected and the way in which the parity condition is forwarded across the bridge.
10.2.1 Configuration Write Transactions to Configuration Space
When PCI 6150 detects a data parity error during a Type-0 configuration write transaction to configuration space,
the following events occur:
• If the parity error response bit is set in the command register, PCI 6150 asserts P_TRDY# and writes the data
to the configuration register. PCI 6150 also asserts P_PERR#.
If the parity error response bit is not set, PCI 6150 does not assert P_PERR#.
• PCI 6150 sets the detected parity error bit in the status register, regardless of the state of the parity error
response bit.
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10.2.2 Read Transactions
When PCI 6150 detects a parity error during a read transaction, the target drives data and data parity, and the
initiator checks parity and conditionally asserts PERR#.
For downstream transactions, when PCI 6150 detects a read data parity error on the secondary bus, the following
events occur:
• PCI 6150 asserts S_PERR# two cycles following the data transfer, if the secondary interface parity error
response bit is set in the bridge control register.
• PCI 6150 sets the detected parity error bit in the secondary status register.
• PCI 6150 sets the data parity detected bit in the secondary status register, if the secondary interface parity
error response bit is set in the bridge control register.
• PCI 6150 forwards the bad parity with the data back to the initiator on the primary bus.
If the data with the bad parity is prefetched and is not read by the initiator on the primary bus, the data is
discarded and the data with bad parity is not returned to the initiator.
• PCI 6150 completes the transaction normally. For upstream transactions, when PCI 6150 detects a read data
parity error on the primary bus, the following events occur:
• PCI 6150 asserts P_PERR# two cycles following the data transfer, if the primary interface parity error
response bit is set in the command register.
• PCI 6150 sets the detected parity error bit in the primary status register.
• PCI 6150 sets the data parity detected bit in the primary status register, if the primary interface parity error
response bit is set in the command register.
• PCI 6150 forwards the bad parity with the data back to the initiator on the secondary bus.
If the data with the bad parity is prefetched and is not read by the initiator on the secondary bus, the data is
discarded and the data with bad parity is not returned to the initiator.
• PCI 6150 completes the transaction normally.
PCI 6150 returns to the initiator the data and parity that was received from the target. When the initiator detects a
parity error on this read data and is enabled to report it, the initiator asserts PERR# two cycles after the data
transfer occurs. It is assumed that the initiator takes responsibility for handling a parity error condition; therefore,
when PCI 6150 detects PERR# asserted while returning read data to the initiator, PCI 6150 does not take any
further action and completes the transaction normally.
10.2.3 Delayed Write Transactions
When PCI 6150 detects a data parity error during a delayed write transaction, the initiator drives data and data
parity, and the target checks parity and conditionally asserts PERR#.
For delayed write transactions, a parity error can occur at the following times:
• During the original delayed write request transaction
• When the initiator repeats the delayed write request transaction
• When PCI 6150 completes the delayed write transaction to the target
When a delayed write transaction is normally queued, the address, command, address parity, data, byte enable
bits, and data parity are all captured and a target retry is returned to the initiator. When PCI 6150 detects a parity
error on the write data for the initial delayed write request transaction, the following events occur:
• If the parity error response bit corresponding to the initiator bus is set, PCI 6150 asserts TRDY# to the initiator
and the transaction is not queued. If multiple data phases are requested, STOP# is also asserted to cause a
target disconnect. Two cycles after the data transfer, PCI 6150 also asserts PERR#.
If the parity error response bit is not set, PCI 6150 returns a target retry and queues the transaction as usual.
Signal PERR# is not asserted. In this case, the initiator repeats the transaction.
• PCI 6150 sets the detected parity error bit in the status register corresponding to the initiator bus, regardless
of the state of the parity error response bit.
Note
If parity checking is turned off and data parity errors have occurred for queued or subsequent delayed write transactions on the
initiator bus, it is possible that the initiator’s reattempts of the write transaction may not match the original queued delayed
write information contained in the delayed transaction queue. In this case, a master timeout condition may occur, possibly
resulting in a system error (P_SERR# assertion).
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For downstream transactions, when PCI 6150 is delivering data to the target on the secondary bus and S_PERR#
is asserted by the target, the following events occur:
• PCI 6150 sets the secondary interface data parity detected bit in the secondary status register, if the
secondary parity error response bit is set in the bridge control register.
• PCI 6150 captures the parity error condition to forward it back to the initiator on the primary bus.
Similarly, for upstream transactions, when the is delivering data to the target on the primary bus and P_PERR# is
asserted by the target, the following events occur:
• PCI 6150 sets the primary interface data parity detected bit in the status register, if the primary parity error
response bit is set in the command register.
• PCI 6150 captures the parity error condition to forward it back to the initiator on the secondary bus.
A delayed write transaction is completed on the initiator bus when the initiator repeats the write transaction with
the same address, command, data, and byte enable bits as the delayed write command that is at the head of the
posted data queue. Note that the parity bit is not compared when determining whether the transaction matches
those in the delayed transaction queues.
Two cases must be considered:
• When parity error is detected on the initiator bus on a subsequent reattempt of the transaction and was not
detected on the target bus
• When parity error is forwarded back from the target bus
• For downstream delayed write transactions, when the parity error is detected on the initiator bus and PCI
6150 has write status to return, the following events occur:
• PCI 6150 first asserts P_TRDY# and then asserts P_PERR# two cycles later, if the primary interface parity
error response bit is set in the command register.
• PCI 6150 sets the primary interface parity error detected bit in the status register.
• Because there was not an exact data and parity match, the write status is not returned and the transaction
remains in the queue.
Similarly, for upstream delayed write transactions, when the parity error is detected on the initiator bus and PCI
6150 has write status to return, the following events occur:
• PCI 6150 first asserts S_TRDY# and then asserts S_PERR# two cycles later, if the secondary interface parity
error response bit is set in the bridge control register.
• PCI 6150 sets the secondary interface parity error detected bit in the secondary status register.
• Because there was not an exact data and parity match, the write status is not returned and the transaction
remains in the queue.
For downstream transactions, in the case where the parity error is being passed back from the target bus and the
parity error condition was not originally detected on the initiator bus, the following events occur:
• PCI 6150 asserts P_PERR# two cycles after the data transfer, if both of the following are true:
♦ The primary interface parity error response bit is set in the command register.
♦ The secondary interface parity error response bit is set in the bridge control register.
• PCI 6150 completes the transaction normally.
For upstream transactions, in the case where the parity error is being passed back from the target bus and the
parity error condition was not originally detected on the initiator bus, the following events occur:
• PCI 6150 asserts S_PERR# two cycles after the data transfer, if both of the following are true:
♦ The primary interface parity error response bit is set in the command register.
♦ The secondary interface parity error response bit is set in the bridge control register.
• PCI 6150 completes the transaction normally.
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10.2.4 Posted Write Transactions
During downstream posted write transactions, when the , responding as a target, detects a data parity error on
the initiator (primary) bus, the following events occur:
• PCI 6150 asserts P_PERR# two cycles after the data transfer, if the primary interface parity error response bit
is set in the command register.
• PCI 6150 sets the primary interface parity error detected bit in the status register.
• PCI 6150 captures and forwards the bad parity condition to the secondary bus.
• PCI 6150 completes the transaction normally.
Similarly, during upstream posted write transactions, when PCI 6150, responding as a target, detects a data parity
error on the initiator (secondary) bus, the following events occur:
• PCI 6150 asserts S_PERR# two cycles after the data transfer, if the secondary interface parity error response
bit is set in the bridge control register.
• PCI 6150 sets the secondary interface parity error detected bit in the secondary status register.
• PCI 6150 captures and forwards the bad parity condition to the primary bus.
• PCI 6150 completes the transaction normally.
During downstream write transactions, when a data parity error is reported on the target (secondary) bus by the
target’s assertion of S_PERR#, the following events occur:
• PCI 6150 sets the data parity detected bit in the secondary status register, if the secondary interface parity
error response bit is set in the bridge control register.
• PCI 6150 asserts P_SERR# and sets the signaled system error bit in the status register, if all of the following
conditions are met:
♦ The SERR# enable bit is set in the command register.
♦ The device-specific P_SERR# disable bit for posted write parity errors is not set.
♦ The secondary interface parity error response bit is set in the bridge control register.
♦ The primary interface parity error response bit is set in the command register.
♦ PCI 6150 did not detect the parity error on the primary (initiator) bus; that is, the parity error was not
forwarded from the primary bus.
During upstream write transactions, when a data parity error is reported on the target (primary) bus by the target’s
assertion of P_PERR#, the following events occur:
• PCI 6150 sets the data parity detected bit in the status register, if the primary interface parity error response
bit is set in the command register.
• PCI 6150 asserts P_SERR# and sets the signaled system error bit in the status register, if all of the following
conditions are met:
♦ The SERR# enable bit is set in the command register.
♦ The secondary interface parity error response bit is set in the bridge control register.
♦ The primary interface parity error response bit is set in the command register.
♦ PCI 6150 did not detect the parity error on the secondary (initiator) bus; that is, the parity error was not
forwarded from the secondary bus.
The assertion of P_SERR# is used to signal the parity error condition in the case where the initiator does not
know that the error occurred. Because the data has already been delivered with no errors, there is no other way
to signal this information back to the initiator.
If the parity error was forwarded from the initiating bus to the target bus, P_SERR# is not asserted.
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10.3 Data Parity Error Reporting Summary
In the previous sections, PCI 6150’s responses to data parity errors are presented according to the type of
transaction in progress. This section organizes PCI 6150’s responses to data parity errors according to the status
bits that PCI 6150 sets and the signals that it asserts.
Table 10–1 shows setting the detected parity error bit in the status register, corresponding to the primary
interface. This bit is set when PCI 6150 detects a parity error on the primary interface.
Table 10–1: Setting the Primary Interface Detected Parity Error Bit
Primary detected
parity error bit
Transaction
type
Direction Bus where error
was detected
Prim./Sec. parity
error response bits
0 Read Downstream Primary x/x1
0 Read Downstream Secondary x/x
1 Read Upstream Primary x/x
0 Read Upstream Secondary x/x
1 Posted write Downstream Primary x/x
0 Posted write Downstream Secondary x/x
0 Posted write Upstream Primary x/x
0 Posted write Upstream Secondary x/x
1 Delayed write Downstream Primary x/x
0 Delayed write Downstream Secondary x/x
0 Delayed write Upstream Primary x/x
0 Delayed write Upstream Secondary x/x
1x = don’t care
Table 10–2 shows setting the detected parity error bit in the secondary status register, corresponding to the
secondary interface. This bit is set when PCI 6150 detects a parity error on the secondary interface.
Table 10–2: Setting the Secondary Interface Detected Parity Error Bit
Sec. Detected
Parity Error Bit
Transaction
Type
Direction Bus Where Error
Was Detected
Prim./Sec. parity
error response bits
0 Read Downstream Primary x/x1
1 Read Downstream Secondary x/x
0 Read Upstream Primary x/x
0 Read Upstream Secondary x/x
0 Posted write Downstream Primary x/x
0 Posted write Downstream Secondary x/x
0 Posted write Upstream Primary x/x
1 Posted write Upstream Secondary x/x
0 Delayed write Downstream Primary x/x
0 Delayed write Downstream Secondary x/x
0 Delayed write Upstream Primary x/x
1 Delayed write Upstream Secondary x/x
1x = don’t care
Table 10–3 shows setting the data parity detected bit in the status register, corresponding to the primary interface.
This bit is set under the following conditions:
• PCI 6150 must be a master on the primary bus.
• The parity error response bit in the command register, corresponding to the primary interface, must be set.
• The P_PERR# signal is detected asserted or a parity error is detected on the primary bus.
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Table 10–3: Setting the Primary Interface Data Parity Detected Bit
Primary data parity
detected bit
Transaction
type
Direction Bus where error
was detected
Prim./Sec. parity
error response bits
0 Read Downstream Primary x/x1
0 Read Downstream Secondary x/x
1 Read Upstream Primary 1/x
0 Read Upstream Secondary x/x
0 Posted write Downstream Primary x/x
0 Posted write Downstream Secondary x/x
1 Posted write Upstream Primary 1/x
0 Posted write Upstream Secondary x/x
0 Delayed write Downstream Primary x/x
0 Delayed write Downstream Secondary x/x
1 Delayed write Upstream Primary 1/x
0 Delayed write Upstream Secondary x/x
1x = don’t care
Table 10–4 shows setting the data parity detected bit in the secondary status register, corresponding to the
secondary interface. This bit is set under the following conditions:
• PCI 6150 must be a master on the secondary bus.
• The parity error response bit in the bridge control register, corresponding to the secondary interface, must be
set.
• The S_PERR# signal is detected asserted or a parity error is detected on the secondary bus.
Table 10–4: Setting the Secondary Interface Data Parity Detected Bit
Secondary data
parity detected bit
Transaction
type
Direction Bus where error
was detected
Prim./Sec. parity error
response bits
0 Read Downstream Primary x/x1
1 Read Downstream Secondary x/1
0 Read Upstream Primary x/x
0 Read Upstream Secondary x/x
0 Posted write Downstream Primary x/x
1 Posted write Downstream Secondary x/1
0 Posted write Upstream Primary x/x
0 Posted write Upstream Secondary x/x
0 Delayed write Downstream Primary x/x
1 Delayed write Downstream Secondary x/1
0 Delayed write Upstream Primary x/x
0 Delayed write Upstream Secondary x/x
1x =don’t care
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Table 10–5 shows assertion of P_PERR#. This signal is set under the following conditions:
• PCI 6150 is either the target of a write transaction or the initiator of a read transaction on the primary bus.
• The parity error response bit in the command register, corresponding to the primary interface, must be set.
• PCI 6150 detects a data parity error on the primary bus or detects S_PERR# asserted during the completion
phase of a downstream delayed write transaction on the target (secondary) bus.
Table 10–5: Assertion of P_PERR#
P_PERR# Transaction
type
Direction Bus where error
was detected
Prim./Sec. parity error
response bits
1 (deasserted) Read Downstream Primary x/x1
1 Read Downstream Secondary x/x
0 (asserted) Read Upstream Primary 1/x
1 Read Upstream Secondary x/x
0 Posted write Downstream Primary 1/x
1 Posted write Downstream Secondary x/x
1 Posted write Upstream Primary x/x
1 Posted write Upstream Secondary x/x
0 Delayed write Downstream Primary 1/x
02 Delayed write Downstream Secondary 1/1
1 Delayed write Upstream Primary x/x
1 Delayed write Upstream Secondary x/x
1x = don’t care
2The parity error was detected on the target (secondary) bus but not on the initiator (primary) bus.
Table 10–6 shows assertion of S_PERR#. This signal is set under the following conditions:
• PCI 6150 is either the target of a write transaction or the initiator of a read transaction on the secondary bus.
• The parity error response bit in the bridge control register, corresponding to the secondary interface, must be
set.
• PCI 6150 detects a data parity error on the secondary bus or detects P_PERR# asserted during the
completion phase of an upstream delayed write transaction on the target (primary) bus.
Table 10-6: Assertion of S_PERR#
S_PERR# Transaction
type
Direction Bus where error
was detected
Prim./Sec. parity
error response bits
1 (deasserted) Read Downstream Primary x/x1
0 (asserted) Read Downstream Secondary x/1
1 Read Upstream Primary x/x
1 Read Upstream Secondary x/x
1 Posted write Downstream Primary x/x
1 Posted write Downstream Secondary x/x
1 Posted write Upstream Primary x/x
0 Posted write Upstream Secondary x/1
1 Delayed write Downstream Primary x/x
1 Delayed write Downstream Secondary x/x
02 Delayed write Upstream Primary 1/1
0 Delayed write Upstream Secondary x/1
1x =don’t care
2The parity error was detected on the target (secondary) bus but not on the initiator (primary) bus.
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Table 10–7 shows assertion of P_SERR#. This signal is set under the following conditions:
• PCI 6150 has detected P_PERR# asserted on an upstream posted write transaction or S_PERR# asserted
on a downstream posted write transaction.
• PCI 6150 did not detect the parity error as a target of the posted write transaction.
• The parity error response bit on the command register and the parity error response bit on the bridge control
register must both be set.
• The SERR# enable bit must be set in the command register.
Table 10–7: Assertion of P_SERR# for Data Parity Errors
P_PERR# Transaction
Type
Direction Bus where error
was detected
Prim./Sec. parity
error response bits
1 (deasserted) Read Downstream Primary x/x1
1 Read Downstream Secondary x/x
1 Read Upstream Primary x/x
1 Read Upstream Secondary x/x
1 Posted write Downstream Primary x/x
02 (asserted) Posted write Downstream Secondary 1/1
03 Posted write Upstream Primary 1/1
1 Posted write Upstream Secondary x/x
1 Delayed write Downstream Primary x/x
1 Delayed write Downstream Secondary x/x
1 Delayed write Upstream Primary x/x
1 Delayed write Upstream Secondary x/x
1x = don’t care
2The parity error was detected on the target (secondary) bus but not on the initiator (primary) bus.
3The parity error was detected on the target (primary) bus but not on the initiator (secondary) bus.
10.4 System Error (SERR#) Reporting
Whenever the assertion of P_SERR# is discussed in this document, it is assumed that the following conditions
apply:
• For PCI 6150 to assert P_SERR# for any reason, the SERR# enable bit must be set in the command register.
• Whenever PCI 6150 asserts P_SERR#, PCI 6150 must also set the signaled system error bit in the status
register.
In compliance with the PCI-to-PCI Bridge Architecture Specification, PCI 6150 asserts P_SERR# when it detects
the secondary SERR# input, S_SERR#, asserted and the SERR# forward enable bit is set in the bridge control
register. In addition, PCI 6150 also sets the received system error bit in the secondary status register.
PCI 6150 also conditionally asserts P_SERR# for any of the following reasons:
• Target abort detected during posted write transaction
• Master abort detected during posted write transaction
• Posted write data discarded after 224 attempts to deliver (224 target retries received)
• Parity error reported on target bus during posted write transaction (see previous section)
• Delayed write data discarded after 224 attempts to deliver (224 target retries received)
• Delayed read data cannot be transferred from target after 224 attempts ( 224 target retries received)
• Master timeout on delayed transaction
The device-specific P_SERR# status register reports the reason for the assertion of P_SERR#.
Most of these events have additional device-specific disable bits in the P_SERR# event disable register that make
it possible to mask out P_SERR# assertion for specific events. The master timeout condition has a SERR#
enable bit for that event in the bridge control register and therefore does not have a device-specific disable bit.
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11 Exclusive Access
This chapter describes the use of the LOCK# signal to implement exclusive access to a target for transactions
that cross PCI 6150. Current revision of the PCI 6150 does not support LOCKed BURST READ cycles.
11.1 Concurrent Locks
The primary and secondary bus lock mechanisms operate concurrently except when a locked transaction crosses
PCI 6150. A primary master can lock a primary target without affecting the status of the lock on the secondary
bus, and vice versa. This means that a primary master can lock a primary target at the same time that a
secondary master locks a secondary target.
11.2 Acquiring Exclusive Access Across PCI 6150
For any PCI bus, before acquiring access to the LOCK# signal and starting a series of locked transactions, the
initiator must first check that both of the following conditions are met:
• The PCI bus must be idle.
• The LOCK# signal must be deasserted.
The initiator leaves the LOCK# signal deasserted during the address phase and asserts LOCK# one clock cycle
later. Once a data transfer is completed from the target, the target lock has been achieved.
Locked transactions can cross PCI 6150 in the downstream and upstream directions, from the primary bus to the
secondary bus and vice versa.
When the target resides on another PCI bus, the master must acquire not only the lock on its own PCI bus but
also the lock on every bus between its bus and the target’s bus. When PCI 6150 detects, on the primary bus, an
initial locked transaction intended for a target on the secondary bus, PCI 6150 samples the address, transaction
type, byte enable bits, and parity. It also samples the lock signal. Because a target retry is signaled to the initiator,
the initiator must relinquish the lock on the primary bus, and therefore the lock is not yet established.
The first locked transaction must be a read transaction. Subsequent locked transactions can be read or write
transactions. Posted Memory Write transactions that are a part of the locked transaction sequence are still
posted. Memory read transactions that are a part of the locked transaction sequence are not prefetched.
When the locked delayed read request is queued, PCI 6150 does not queue any more transactions until the
locked sequence is finished. PCI 6150 signals a target retry to all transactions initiated subsequent to the locked
read transaction that are intended for targets on the other side of PCI 6150. PCI 6150 allows any transactions
queued before the locked transaction to complete before initiating the locked transaction.
When the locked delayed read request transaction moves to the head of the delayed transaction queue, PCI 6150
initiates the transaction as a locked read transaction by deasserting LOCK# on the target bus during the first
address phase, and by asserting LOCK# one cycle later. If LOCK# is already asserted (used by another initiator),
PCI 6150 waits to request access to the secondary bus until LOCK# is sampled deasserted when the target bus
is idle. Note that the existing lock on the target bus could not have crossed PCI 6150; otherwise, the pending
queued locked transaction would not have been queued. When PCI 6150 is able to complete a data transfer with
the locked read transaction, the lock is established on the secondary bus.
When the initiator repeats the locked read transaction on the primary bus with the same address, transaction
type, and byte enable bits, PCI 6150 transfers the read data back to the initiator, and the lock is then also
established on the primary bus.
For PCI 6150 to recognize and respond to the initiator, the initiator’s subsequent attempts of the read transaction
must use the locked transaction sequence (deassert LOCK# during address phase, and assert LOCK# one cycle
later). If the LOCK# sequence is not used in subsequent attempts, a master timeout condition may result. When a
master timeout condition occurs, SERR# is conditionally asserted, the read data and queued read transaction are
discarded, and the LOCK# signal is deasserted on the target bus.
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Once the intended target has been locked, any subsequent locked transactions initiated on the initiator bus that
are forwarded by PCI 6150 are driven as locked transactions on the target bus.
When PCI 6150 receives a target abort or a master abort in response to the delayed locked read transaction, this
status is passed back to the initiator, and no locks are established on either the target or the initiator bus. PCI
6150 resumes forwarding unlocked transactions in both directions.
11.3 Ending Exclusive Access
After the lock has been acquired on both the initiator and target buses, PCI 6150 must maintain the lock on the
target bus for any subsequent locked transactions until the initiator relinquishes the lock.
The only time a target retry causes the lock to be relinquished is on the first transaction of a locked sequence. On
subsequent transactions in the sequence, the target retry has no effect on the status of the lock signal.
An established target lock is maintained until the initiator relinquishes the lock. PCI 6150 does not know whether
the current transaction is the last one in a sequence of locked transactions until the initiator deasserts the LOCK#
signal at the end of the transaction.
When the last locked transaction is a delayed transaction, PCI 6150 has already completed the transaction on the
secondary bus. In this case, as soon as PCI 6150 detects that the initiator has relinquished the LOCK# signal by
sampling it in the deasserted state while FRAME# is deasserted, PCI 6150 deasserts the LOCK# signal on the
target bus as soon as possible. Because of this behavior, LOCK# may not be deasserted until several cycles after
the last locked transaction has been completed on the target bus. As soon as PCI 6150 has deasserted LOCK# to
indicate the end of a sequence of locked transactions, it resumes forwarding unlocked transactions.
When the last locked transaction is a posted write transaction, PCI 6150 deasserts LOCK# on the target bus at
the end of the transaction because the lock was relinquished at the end of the write transaction on the initiator
bus.
When PCI 6150 receives a target abort or a master abort in response to a locked delayed transaction, PCI 6150
returns a target abort or a master abort when the initiator repeats the locked transaction. The initiator must then
deassert LOCK# at the end of the transaction. PCI 6150 sets the appropriate status bits, flagging the abnormal
target termination condition. Normal forwarding of unlocked posted and delayed transactions is resumed.
When PCI 6150 receives a target abort or a master abort in response to a locked posted write transaction, PCI
6150 cannot pass back that status to the initiator. PCI 6150 asserts SERR# on the initiator bus when a target
abort or a master abort is received during a locked posted write transaction, if the SERR# enable bit is set in the
command register. Signal SERR# is asserted for the master abort condition if the master abort mode bit is set in
the bridge control register.
Note:
PCI 6150 has an option to ignore the lock protocol, through register 46h, bits 13 and 14.
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12 PCI Bus Arbitration
PCI 6150 must arbitrate for use of the primary bus when forwarding upstream transactions, and for use of the
secondary bus when forwarding downstream transactions. The arbiter for the primary bus resides external to PCI
6150, typically on the motherboard. For the secondary PCI bus, PCI 6150 implements an internal arbiter. This
arbiter can be disabled, and an external arbiter can be used instead.
This chapter describes primary and secondary bus arbitration.
12.1 Primary PCI Bus Arbitration
PCI 6150 implements a request output pin, P_REQ#, and a grant input pin, P_GNT#, for primary PCI bus
arbitration. PCI 6150 asserts P_REQ# when forwarding transactions upstream; that is, it acts as initiator on the
primary PCI bus. As long as at least one pending transaction resides in the queues in the upstream direction,
either posted write data or delayed transaction requests, PCI 6150 keeps P_REQ# asserted. However, if a target
retry, target disconnect, or a target abort is received in response to a transaction initiated by PCI 6150 on the
primary PCI bus, PCI 6150 deasserts P_REQ# for two PCI clock cycles. For all cycles through the bridge,
P_REQ# is not asserted until the transaction request has been completely queued.
If P_GNT# is asserted (by the primary bus arbiter after PCI 6150 has asserted P_REQ#), PCI 6150 initiates a
transaction on the primary bus during the next PCI clock cycle. When P_GNT# is asserted to PCI 6150 when
P_REQ# is not asserted, PCI 6150 parks P_AD, P_CBE, and P_PAR by driving them to valid logic levels. When
the primary bus is parked at PCI 6150 and PCI 6150 then has a transaction to initiate on the primary bus, PCI
6150 starts the transaction if P_GNT# was asserted during the previous cycle.
12.2 Secondary PCI Bus Arbitration
PCI 6150 implements an internal secondary PCI bus arbiter. This arbiter supports nine external masters in
addition to PCI 6150. The internal arbiter can be disabled, and an external arbiter can be used instead for
secondary bus arbitration.
12.2.1 Secondary Bus Arbitration Using the Internal Arbiter
To use the internal arbiter, the secondary bus arbiter enable pin, S_CFN#, must be tied LOW. PCI 6150 has nine
secondary bus request input pins, S_REQ#[8:0], and nine secondary bus output grant pins, S_GNT#[8:0], to
support external secondary bus masters. The secondary bus request and grant signals are connected internally to
the arbiter and are not brought out to external pins when S_CFN# is HIGH.
PCI 6150 has a 2-level arbitration scheme in which arbitration is divided into two groups, a high priority group and
a low priority group. The low priority group as a whole represents one entry in the high priority group; that is, if the
high priority group consists of n masters, then in at least every n+1 transactions the highest priority is assigned to
the low priority group. Priority changes evenly among the low priority group. Therefore, members of the high
priority group can be serviced n transactions out of n+1, while one member of the low priority group is serviced
once every n+1 transactions. Each master can be assigned to either the low priority group or the high priority
group, through configuration register 42h.
Each group can be programmed to use a rotating priority or a fixed priority scheme, through configuration register
50h.
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12.2.1.1 Rotating Priority Scheme
The secondary arbiter supports a programmable 2-level rotating algorithm that takes care of 10 requests/grants,
including the PCI 6150. Figure 12–1 shows an example of an internal arbiter where four masters, including PCI
6150, are in the high priority group, and six masters are in the low priority group. Using this example, if all
requests are always asserted, the highest priority rotates among the masters in the following fashion (high priority
members are given in italics, low priority members, in boldface type):
B, m0, m1, m2, B, m0, m1, m3, B, m0, m1, m4, B, m0, m1, m5, and so on.
B
m0
m1
m2
lpg
m3
m4
m5
m6
m7
m8
Figure 12-1 Secondary Arbiter Example
If all the masters are assigned to one group, the algorithm defaults to a rotating priority among all the masters.
After reset, all external masters are assigned to the low priority group, and PCI 6150 is assigned to the high
priority group. PCI 6150 receives highest priority on the target bus every other transaction, and priority rotates
evenly among the other masters.
Priorities are reevaluated every time S_FRAME# is asserted, that is, at the start of each new transaction on the
secondary PCI bus. From this point until the time that the next transaction starts, the arbiter asserts the grant
signal corresponding to the highest priority request that is asserted. If a grant for a particular request is asserted,
and a higher priority request subsequently asserts, the arbiter deasserts the asserted grant signal and asserts the
grant corresponding to the new higher priority request on the next PCI clock cycle. When priorities are
reevaluated, the highest priority is assigned to the next highest priority master relative to the master that initiated
the previous transaction. The master that initiated the last transaction now has the lowest priority in its group.
Priority is also re-evaluated if the requesting agent deasserts its request without generating any cycles while it
was granted.
If PCI 6150 detects that an initiator has failed to assert S_FRAME# after 16 cycles of both grant assertion and a
secondary idle bus condition, the arbiter will re-evaluate grant assignment.
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12.2.1.2 Fixed Priority Scheme
PCI 6150 also has support for a fixed priority scheme within the two priority groups. In this case, configuration
register 50h, bit 0 and 2 controls whether the low priority group or the high priority group will use fixed or rotating
priority scheme. If a fixed priority scheme is used, then a master within the group is assigned to have the highest
priority within its group, and then an option is set to control the priority of other masters relative to the highest
priority master. This is controlled through bits 4-11 and bits 1 and 3 of the Internal Arbiter Control register (reg.
50h). For example, using the previous example with the groups at fixed priority, if master 7 has the highest priority
of the low priority group, and PCI 6150 has the highest priority of the high priority group, and priority decreases in
ascending order of masters for both groups, (bits 1,3 of register 50 are set to 1). The order of priority with the
highest first, will be as follows:
B, m0, m1, m2, m7, m8, m3, m4, m5, m6
If bits 1, 3 or register 50 are set to 0, priority will decrease in the other direction , so the order becomes:
B, m2, m1, m0, m7, m6, m5, m4, m3, m8
To prevent bus contention, if the secondary PCI bus is idle, the arbiter never asserts one grant signal in the same
PCI cycle in which it deasserts another. It deasserts one grant, and then asserts the next grant, no earlier than
one PCI clock cycle later. If the secondary PCI bus is busy, that is, either S_FRAME# or S_IRDY# is asserted, the
arbiter can deassert one grant and assert another grant during the same PCI clock cycle.
12.2.2 Secondary Bus Arbitration using an External Arbiter
The internal arbiter is disabled when the secondary bus central function control pin, S_CFN#, is tied HIGH. An
external arbiter must then be used.
When S_CFN# is tied HIGH, PCI 6150 reconfigures two pins to be external request and grant pins. The
S_GNT#[0] pin is reconfigured to be the PCI 6150’s external request pin because it is output. The S_REQ#[0] pin
is reconfigured to be the external grant pin because it is input. When an external arbiter is used, PCI 6150 uses
the S_GNT#[0] pin to request the secondary bus. When the reconfigured S_REQ#[0] pin is asserted LOW after
PCI 6150 has asserted S_GNT#[0], PCI 6150 initiates a transaction on the secondary bus one cycle later. If grant
is asserted and PCI 6150 has not asserted the request, PCI 6150 parks the AD, CBE and PAR pins by driving
them to valid logic levels.
The unused secondary bus grant outputs, S_GNT#<8:1> are driven HIGH. Unused secondary bus request inputs,
S_REQ#<8:1> should be pulled HIGH.
12.2.3 Internal Arbitration Parking
If the internal secondary bus arbiter is enabled, the secondary arbiter can be optionally parked at the last active
slot, or on any of the designated slots, and it can also be disabled.
PCI 6150 has the following options related to arbitration parking:
• No parking: all grants are deasserted if there are no requests asserted.
• Fixed parking: grant can be assigned to a specified master.
• Last master granted: grant is assign to the last granted master.
These options are selected through Internal Arbiter Control register at 50h, bits 12-15.
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13 General Purpose I/O Interface
The PCI 6150 implements a 4 general-purpose I/O (GPIO) interface pins. During normal operation, the
configuration registers control GPIO interface. In addition, the GPIO pins can be used for the following functions:
• During Secondary Reset, the GPIO interface can be used to shift in a 16-bit serial stream that serves as a
secondary bus clock disable mask.
• A live insertion bit can be used, along with the GPIO[3] pin, to bring the PCI 6150 gracefully to a halt
through hardware, permitting live insertion of option cards behind the PCI 6150.
Table 13-1: GPIO Pin Alternate Functions
GPIO Pin Alternate Function
GPIO0 – pull-up
Functions as shift register clock output when PRST# asserted.
GPIO1 – pull-up
GPIO2 – pull-up Functions as shift/load control output to shift register when PRST# asserted
GPIO3 – pull-up Can be used for live insertion function, if set as input and live insertion mode bit is
set. If high, transaction forwarding is disabled.
13.1 GPIO Control Registers
During normal operation, the GPIO interface is controlled by the following configuration registers:
• The GPIO output data register
• The GPIO output enable control register
• The GPIO input data register
GPIO3-0 consist of five 8-bit fields:
• Write-1-to-set output data field
• Write-1-to-clear output data field
• Write-1-to-set signal output enable control field
• Write-1-to-clear signal output enable control field
• Input data field
The output enable fields control whether each GPIO signal is input or output. Each signal is controlled
independently by a bit in each output enable control field. If a 1 is written to the write-1-to-set field, the
corresponding pin is activated as an output. If a 1 is written to the write-1-to-clear field, the output driver is three-
stated, and the pin is then input only. Writing zeros to these registers has no effect. The reset state for these
signals is input only. The input data field is read only and reflects the current value of the GPIO pins. A Type-0
configuration read operation to this address is used to obtain the values of these pins. All pins can be read at any
time, whether configured as input only or as bi-directional. The output data fields also use the write-1-to-set and
write-1-to-clear method. If a 1 is written to the write-1-to-set field and the pin is enabled as an output, the
corresponding GPIO output is driven high. If a 1 is written to the write-1-to-clear field and the pin is enabled as an
output, the corresponding GPIO output is driven low. Writing zeros to these registers has no effect. The value
written to the output register will be driven only when the GPIO signal is configured as output. Type-0
configuration write operation is used to program these fields. The reset value for the output is 0.
PCI 6150 Data Book v2.0
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14 Clocks
This chapter provides information about the clocks.
14.1 Primary and Secondary Clock Inputs
PCI 6150 implements a separate clock input for each PCI interface. The primary interface is synchronized to the
primary clock input, P_CLKIN, and the secondary interface is synchronized to the secondary clock input,
S_CLKIN.
PCI 6150 operates at a maximum frequency of 66 MHz. Output clocks S_CLK[9:0] can be derived from P_CLKIN
either at the same frequency, at P_CLKIN / 2, or at an asynchronous frequency.
PCI 6150 primary and secondary clock inputs can be asynchronous. The skew between P_CLKIN and S_CLKIN
is irrelevant. PCI 6150 can tolerate a 1:2.5 or 2.5:1 frequency ratio between primary and secondary clock inputs.
14.2 Secondary Clock Outputs
PCI 6150 has 10 secondary clock outputs that can be used as clock inputs for up to nine external secondary bus
devices with one feedback to S_CLKIN.
The rules for using secondary clocks are:
• Each secondary clock output is limited to no more than 1 PCI load.
• All clock trace length, including feedback clock to the PCI 6150, must have equal length and impedance.
• Terminating or disabling unused secondary clock outputs is recommended to reduce power dissipation and
noise in the system.
14.3 Disabling Unused Secondary Clock Outputs
When secondary clock outputs are not used, both GPIO[3:0] and MSK_IN can be used to clock in a serial mask
that selectively three-states secondary clock outputs. See GPIO section for details in this application.
After the serial mask has been shifted into the PCI 6150, the value of the mask is readable and can be changed in
the secondary clock disable mask register. When the mask is modified by a configuration write operation to this
register, the new clock mask disables the appropriate secondary clock outputs within a few cycles. This feature
allows software to disable or enable secondary clock outputs based on the presence of option cards, and so on.
PCI 6150 delays deasserting the secondary reset signal, S_RSTOUT#, until the serial clock mask has been
completely shifted in and the secondary clocks have been disabled or enabled, according to the mask. The delay
between P_RSTIN# assertion and S_RSOUT# deassertion is 16-32 clocks.
14.3.1 Secondary Clock Control
The PCI 6150 uses the GPIO pins and the MSKIN signal to input a 16-bit serial data stream. This data stream is
shifted into the secondary clock control register and is used for selectively disabling secondary clock outputs. The
serial data stream is shifted in as soon as P_RSTIN# is detected deasserted and the secondary reset signal,
S_RSTOUT#, is detected asserted. The deassertion of S_RSTOUT# is delayed until the PCI 6150 completes
shifting in the clock mask data, which takes 16 clock cycles (32 cycles if operating at 66 MHz). After that, the
GPIO pins can be used as general purpose I/O pins.
An external shift register should be used to load and shift the data. The GPIO pins are used for shift register
control and serial data input. The data is input through the dedicated input signal, MSKIN. The shift register
circuitry is not necessary for correct operation of the PCI 6150. The shift registers can be eliminated, and MSKIN
can be tied low to enable all secondary clock outputs or tied high to force all secondary clock outputs high.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 95
GPIO Shift Register Operation
GPIO Pin Operation
GPIO[0] Shift register clock output at 33 MHz maximum frequency.
GPIO[2]
0
1
Load
Shift
Shift Register control:
GPIO Serial Data Format
Bit Description SCLK_O OUTPUT
[1:0] Slot 0 PRSNT#<1:0> or device 0 0
[3:2] Slot 1 PRSNT#<1:0> or device 1 1
[5:4] Slot 2 PRSNT#<1:0> or device 2 2
[7:6] Slot 3 PRSNT#<1:0> or device 3 3
[8] Device 4 4
[9] Device 5 5
[10] Device 6 6
[11] Device 7 7
[12] Device 8 8
[13] Can be used for PCI 6150 S_CLKIN input 9
[14] Reserved Not applicable
[15] Reserved Not applicable
The first eight bits contain the PRSNT#[1:0] signal values for four slots, and these bits control the SCLKO[3:0]
outputs. If one or both of the PRSNT#[1:0] signals are 0, that indicates that a card is present in the slot and
therefore the secondary clock for that slot is not masked. If these clocks are connected to devices and not to
slots, one or both of the bits should be tied low to enable the clock. The next five bits are the clock mask for
devices; each bit enables or disables the clock for one device. These bits control the SCLKO[8:4] outputs: 0
enables the clock, and 1 disables the clock. Bit 13 is the clock enable bit for SCLKO[9], which is connected to the
PCI 6150’s SCLKIN input. If desired, the assignment of SCLKO clock outputs to slots, devices, and the PCI
6150’s SCLKIN input can be rearranged from the assignment shown here. However, it is important that the serial
data stream format match the assignment of SCLKO outputs. The GPIO pin serial protocol is designed to work
with two 74F166 8-bit shift registers.
14.4 Using an External Clock Source
PCI 6150 has 2 signals, OSC_SEL# and OSC_IN which can be used to connect an external clock source to the
PCI 6150. During normal operation, PCI 6150 generates S_CLK[9:0] outputs based on the PCI CLK source. If
OSCSEL# is low, PCI 6150 will derive S_CLK[9:0] outputs from the OSCIN signal instead. Clock division will still
be performed on the OSCIN clock depending on the states of the P_M66EN and S_M66EN signals.
PCI 6150 also has S_CLK_STB input allowing designer to indicate the Secondary external clock source is stable.
If this input is 0 indicating that the S_CLKIN is not yet stable, the PCI 6150 will not let S_RSTOUT# deassert.
PCI 6150 Data Book v2.0
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14.5 Frequency Division options
The PCI 6150 has built-in frequency division options to automatically adjust the output clocks S_CLK[9:0] for
66Mhz or 33Mhz operations. The following table depicts division conditions.
P_M66EN S_M66EN DIVISION
111/1
101/2
011/1
001/1
Notes
1. S_M66EN pin cannot be floating.
2. In Revision BA, the PCI 6154 does not drive S_M66EN to low when P_M66EN is low.
3. In Revision BB, the PCI 6154 drives S_M66EN to low when P_M66EN is low.
14.6 Running Secondary Port Faster than Primary Port
PCI 6150 allows running the Secondary port at a faster rate than the Primary port. PCI 6150 asynchronous design
supports standard 66Mhz to 33MHz and faster secondary port speed such as 33Mhz to 66MHz conversion. Designers must
provide the faster clock source either through an oscillator or a clock generator. If OSCIN is used to make use of
the SCLKn outputs, the division control can be disabled by pulling the S_M66EN pin HIGH and not connecting
this pin to the PCI slots. Otherwise external clock can be fed directly into the S_CLKIN.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 97
15 Frequency Operation
PCI 6150 supports up to 66 MHz operations. CFG66 and PM66EN pin inputs should be HIGH for 66MHz
operation.
15.1 66-MHZ operation
Signal CFG66 must be tied high on the board to enable 66MHz operation and to set the 66MHz Capable bit in the
Status register and the Secondary Status register in configuration space.
Signals P_M66EN and S_M66EN indicate whether the primary and secondary interfaces, respectively are
operating at 66MHz. This information is needed to control the frequency of the secondary bus. Note that the PCI
Local Bus Specification, Revision 2.2 restricts clock frequency changes above 33MHz to during PCI reset only.
The following primary and secondary bus frequency combinations are supported when using the Primary
P_CLKIN to generate the secondary clock outputs:
• 66MHz primary bus, 66MHz secondary bus
• 66MHz primary bus, 33MHz secondary bus
• 33MHz primary bus, 33MHz secondary bus
If P_M66EN is low (66MHz capable, primary bus at 33MHz), then the PCI 6150 drives LOW S_M66EN to indicate
that the secondary bus is operating at 33MHz. If Designers want to run the secondary bus at faster than primary
bus, S_M66EN need not be connected to secondary PCI devices.
PCI 6150 can also generate S_CLK outputs from the OSCIN input if enabled. When PCI 6150 is running with
external clock input that is not generated from S_CLK[9:0] outputs, the P_M66EN and S_M66EN controlled clock
division will not apply.
When OSCIN or other external clock inputs are used for the secondary port, PCI 6150 can run with a maximum
ratio of 1:2.5 or 2.5:1 between primary and secondary bus clocks.
PCI 6150 Data Book v2.0
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16 Reset
This chapter describes the primary interface, secondary interface, and chip reset mechanisms. There are also
Power Management initiated internal reset and software controlled internal reset.
Note:
After any of the resets are deasserted, PCI 6150 requires 32 clocks to initialize the bridge functions.
16.1 Primary Reset Input
PCI 6150 requires at least 2 clocks before P_RSTIN# rising edge to reset properly.
When P_RSTIN# is asserted, the following events occur:
• PCI 6150 three-states all primary PCI interface signals, except S_RSTOUT#, S_GNT#[8:0], SCLKO[9:0]
within 1 clock.
• Active P_RSTIN# will cause Secondary port reset. 43 clocks after P_RSTIN# going HIGH, S_RSTOUT# will
go HIGH.
• Clock disable bits begin to be shifted in at the rising edge of P_RSTIN#.
The P_RSTIN# asserting and deasserting edges can be asynchronous to P_CLK and S_CLK. PCI 6150 requires
32 primary port PCI clocks after P_RSTIN# rising edge to reset its internal logic.
When P_RSTIN# is asserted, all posted write and delayed transaction data buffers are reset; therefore, any
transactions residing in buffers at the active time of P_RSTIN# are discarded.
16.2 Secondary Reset Output
PCI 6150 asserts S_RSTOUT# when any of the following conditions is met:
• Signal P_RSTIN# is asserted.
Signal S_RSTOUT# remains asserted as long as P_RSTIN# is asserted and does not deassert until
P_RSTIN# is deasserted, or while the secondary clock serial disable mask is being shifted in (16 clock cycles
after P_RSTIN# deassertion).
• The Secondary Reset bit in the bridge control register is set. Signal S_RSTOUT# remains asserted until the
rest control bit is cleared.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 99
16.3 Software Chip Reset
The chip reset bit (register 41h, bit 0) in the diagnostic control register can be used to reset the entire PCI 6150
except that it will NOT cause S_RSTOUT# to go active and it will NOT three-states the signals.
When the chip reset bit is set, all registers and chip state are reset. Within 4 PCI clock cycles after completion of
the configuration write operation that sets the chip reset bit, the chip reset bit automatically clears and the chip is
ready for configuration.
During chip reset, PCI 6150 is inaccessible.
16.4 Power Management internal Reset
When there is a D3hot to D0 transition with Power Management Control registers bit 1:0 programmed to D0, an
internal reset equivalent to P_RSTIN# input will be generated and all relevant registers will be reset. However
S_RSTOUT# will NOT be active.
16.5 Reset inputs Table
The following table depicts the effect of different PCI 6150 RESET INPUT sources.
Operating Mode
Reset Inputs
Transparent Mode
P_RSTIN# - Resets Primary and Secondary Ports
- Causes S_RSTOUT# active
- Causes EEPROM load
S_RSTOUT# - Not used as input
Register 41h bit 0 Chip Reset - Resets internal state machines
Register 3Eh bit 6 Secondary Reset - Resets only Secondary Port
- Causes S_RSTOUT# active
PCI 6150 Data Book v2.0
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17 Bridge Behavior
A PCI cycle is initiated by asserting the FRAME# signal. In a bridge, there are a number of possibilities. These are
summarized in the table below. Table 17-1 shows PCI 6150’s actions for different cycle types.
Table 17-1: Bridge Actions for Various Cycle Types
Initiator Target Response
Master on primary Target on Primary PCI 6150 does not respond. It detects this situation by
decoding the address as well as monitoring the
P_DEVSEL# for other fast and medium devices on the
primary port.
Master on primary Target on secondary PCI 6150 asserts P_DEVSEL#, terminate the cycle
normally if able to posted, otherwise return with a retry.
Then passes the cycle to the appropriate port. When cycle
is complete on the target port, it will wait for the initiator to
repeat the same cycle and end with normal termination.
Master on primary Target not on primary nor
secondary port
PCI 6150 does not respond and the cycle will terminate as
master abort.
Master on secondary Target on the same
secondary port
PCI 6150 does not respond.
Master on secondary Target on primary or the
other secondary port
PCI 6150 asserts S_DEVSEL#, terminate the cycle
normally if able to posted, otherwise return with a retry.
Then passes the cycle to the appropriate port. When cycle
is complete on the target port, it will wait for the initiator to
repeat the same cycle and end with normal termination.
Master on secondary Target not on primary nor
the other secondary
PCI 6150 does not respond.
A target then has up to three cycles to respond before subtractive decoding is initiated. If the target detects an
address hit, it should assert its DEVSEL# signal in the cycle corresponding to the values of bits 9 and 10 in the
Configuration Status Register.
Termination of a PCI cycle can occur in a number of ways. Normal termination begins by the initiator (master)
deasserting FRAME# with IRDY# being asserted (or remaining asserted) on the same cycle. The cycle completes
when TRDY# and IRDY# are both asserted simultaneously. The target should deassert TRDY# for one cycle
following final assertion (sustained three-state signal).
17.1 Abnormal Termination (Initiated by Bridge Master)
17.1.1 Master Abort
Master abort indicates that PCI 6150 acting as a master receives no response (i.e., no target asserts
P_DEVSEL# or S_DEVSEL#) from a target. the bridge deasserts FRAME# and then deasserts IRDY#.
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17.2 Parity and Error Reporting
Parity must be checked for all addresses and write data. Parity is defined on the P_PAR and S_PAR signals.
Parity should be even (i.e. an even number of ‘1’s) across AD, CBE, and PAR. Parity information on PAR is valid
the cycle after AD and CBE are valid.
17.2.1 Reporting Parity Errors
For all address phases, if a parity error is detected, the error is reported on the P_SERR# signal by asserting
P_SERR# for one cycle and then three-stating two cycles after the bad address. P_SERR# can only be asserted
if bit 6 and 8 in the Command Register are both set to 1. For write data phases, a parity error is reported by
asserting the P_PERR# signal two cycles after the data phase and should remain asserted for one cycle when bit
8 in the Command register is set to a 1. The target reports any type of data parity errors during write cycles, while
the master reports data parity errors during read cycles.
Detection of an address parity error will cause the PCI bridge target to not claim the bus (P_DEVSEL# remains
inactive) and the cycle will then terminate with a Master Abort. When the bridge is acting as master, a data parity
error during a read cycle results in the bridge master initiating a Master Abort.
17.3 Secondary IDSEL Mapping
When PCI 6150 detects a Type-1 configuration transaction for a device connected to the secondary, it translates
the Type-1 transaction to Type-0 transaction on the downstream interface. Type-1 configuration format uses a 5-
bit field at P_AD[15:11] as a device number. This is translated to S_AD[31:16] by PCI 6150. Table 17-2 explains
how PCI 6150 generates the secondary IDSELs. No device is permitted to connect IDSEL to AD[16] (the source
bridge is device number 0). PCI 6150 is the source bridge for its secondary bus.
Table 17-2: Generation of S_IDSEL.
P_AD[15:11] S_AD[31:16] Device Number S_AD bit
0 0000b
0 0001b
0 0010b
…
0 1011b
0 1100b
…
0 1111b
1 xxxxb
0000 0000 0000 0001b
0000 0000 0000 0010b
0000 0000 0000 0100b
…
0000 1000 0000 0000b
0001 0000 0000 0000b
…
1000 0000 0000 0000b
0000 0000 0000 0000b
0 (Source Bridge)
1
2
…
11
12
…
15
Special Cycle
16
17
18
…
27
28
…
31
N/A
PCI 6150 Data Book v2.0
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18 Flow Through Optimization
PCI 6150 has several options that can be used to optimize PCI transfers once flow though mode through the
bridge is achieved.
During flow through posted write cycles, if there is only 1 data transfer pending in the internal post memory write
queue, PCI 6150 can be programmed to wait for a specified number of clocks before disconnecting. PCI 6150 will
deassert IRDY# on the target side and wait for up to 7 clocks for more data from the initiator. If during this period
new write data is received from the initiator, PCI 6150 will reassert IRDY# and continue with the write cycle. If no
new write data is received during this period, the PCI 6150 will terminate the cycle to the target with the last data
from the queue and finish the cycle at a later time.
For flow through delayed read cycles, if the internal read queue is almost full, PCI 6150 can be programmed to
wait for a specified number of clocks for read data from the target before disconnecting. During this time, the PCI
6150 will deassert IRDY# from the read source and wait for up to 7 clocks. If additional space becomes available
in the read queue before the end of IRDY# inactive period, PCI 6150 will reassert IRDY# and proceed with the
next read data phase. If no additional space becomes available in the read queue, the current data phase will
become the last one (IRDY# is asserted, FRAME# is deasserted) and the cycle will terminate at the end of the
data phase.
18.1 Read Cycle Optimization
The main function is to increase the probability of flow-through occurring during read access to prefetchable
memory regions. In the case that flow-through does not occur, it would be inefficient for the PCI 6150 to prefetch
too little or too much data. If PCI 6150 prefetches too little and flow-through does not occur, then the read cycles
become divided into multiple cycles. If PCI 6150 prefetches too much data and the internal FIFOs fill, it has to wait
for the initiator to retry the previous read cycle, and then flush unclaimed data before it can enqueue subsequent
cycles. The prefetch count registers can be used to tune the PCI 6150 for various PCI masters.
The initial count is equivalent to the cache line size, and assumes that a master will want at least 1 cache line of
data. The incremental count is only used when PCI 6150 does not detect flow-through for the current cycle being
prefetched during the initial fetch count. PCI 6150 will continue prefetching in increments until the maximum count
is reached, then disconnect the cycle.
For read prefetching, the PCI 6150 implements several registers that control the amount of data prefetched on the
secondary and primary PCI bus. The following registers can be used to optimize PCI 6150 performance during
read cycles:
• Primary Initial Prefetch Maximum Count
• Primary Incremental Prefetch Count
• Primary Maximum Prefetch Count
• Secondary Initial Prefetch Maximum Count
• Secondary Incremental Prefetch Count
• Secondary Maximum Prefetch Count
The PCI 6150 will prefetch either until flow-through or until prefetch must stop based on the following conditions:
(IPMC + IPC + IPC + … + IPC) < MPC where IPC < ½ MPC
IPMC = Initial Prefetch Maximum Count
IPC = Incremental Prefetch Count
MPC = Maximum Prefetch Count
If the prefetch count has not reached MPC and flow through has been achieved, the PCI 6150 will keep on
prefetching until the requesting master terminates the prefetch request. Otherwise, when MPC has been reached,
the PCI 6150 will not prefetch any more.
The incremental prefetch can be disabled by setting IPC >= MPC.
PCI 6150 Data Book v2.0
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18.1.1 Primary/Secondary Initial Prefetch Count
This count controls the amount of data initially prefetched by the PCI 6150 on the primary/secondary bus during
reads to the prefetchable memory region. This assumes there is enough space in the internal FIFO. If flow
through is achieved during this initial prefetch, PCI 6150 will continue prefetching beyond this count.
18.1.2 Primary/Secondary Incremental Prefetch Count
This register controls the amount of prefetching done after the initial prefetch. If flow-through was not achieved
during the initial prefetch, PCI 6150 will try to prefetch more data, until the FIFO fills, or until the maximum
prefetch count is reached.
18.1.3 Primary/Secondary Maximum Prefetch Count
This register limits the amount of prefetched data for a single entry available in the internal FIFO at any time.
During subsequent read prefetch cycles, the PCI 6150 will disconnect the cycle when the count of data in the
FIFO for the current cycle reaches this value, and flow-through has not been achieved.
18.2 Read Prefetch Boundaries
For memory read and memory read line commands, PCI 6150 prefetches from the starting address up until the
address with offset equals to the Initial Prefetch count. For example, if Initial Prefetch count equals 20H and the
starting address is 10H, PCI 6150 will only prefetch 10H (20H-10H) count and afterward will start incremental
prefetch until the Maximum Prefetch count is reached, or flow through is achieved. The exception is that if the
Initial Prefetch Count (IPC) and starting address offset difference (IPC – Starting address offset) is less than 3
transfers apart, the PCI 6150 will not activate incremental prefetch.
For memory read multiple commands, if the starting address is not 0, PCI 6150 will first prefetch from the
starting address up until the address with offset equals to the Initial Prefetch count. Afterwards the PCI 6150 will
additionally prefetch one “Initial Prefetch count” count. For example, if Initial Prefetch count equals 20H and the
starting address is 10H, PCI 6150 will first prefetch 10H (20H-10H) count and then continues to prefetch another
20H count. Afterwards, incremental prefetch is invoked until the Maximum Prefetch count is reached, or flow
through is achieved.
PCI 6150 Data Book v2.0
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19 IEEE 1149.1 Compatible JTAG Controller
An IEEE 1149.1 compatible Test Access Port (TAP) controller and the associated TAP pins are provided for
board level continuity test and diagnostics. The TAP pins assigned are TCK, TDI, TDO, TMS and TRST#. All
digital input, output, input/output pins are tested except the TAP pins and clock pin.
The IEEE 1149.1 Test Logic consists of a TAP controller, an instruction register, and a group of test data registers
including Bypass, Device Identification and Boundary Scan registers. The TAP controller is a synchronous 16
state machine driven by the Test Clock (TCK) and the Test Mode Select (TMS) pins. An independent power on
reset circuit is provided to ensure the machine is in RESET state at power-up.
PCI 6150 implements 3 basic instructions: BYPASS, SAMPLE/PRELOAD, and EXTEST.
PCI 6150 Data Book v2.0
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20 EEPROM
Important: Wrong EEPROM data can cause the PCI 6150 to lock the system. Designers should provide an
optional switch to disable the EEPROM in their board design.
PCI 6150 has an interface to EEPROM device. The interface can control an ISSI IS24C02 or compatible part,
which is organized as 256X8 bits. The EEPROM is used to initialize the registers. After P_RSTIN# is deasserted,
PCI 6150 will automatically load data from the EEPROM. The data structure is defined in the following section.
The EEPROM interface is organized on 16-bit base in little-endian format, and PCI 6150 supplies a 7-bit
EEPROM word address.
The following pins are used for the EEPROM interface:
• EEPCLK: EEPROM clock output
• EEPDATA: EEPROM bi-directional serial data pin
• EE_EN#: LOW input enables EEPROM access.
Note: The PCI 6150 does not control the EEPROM address inputs. It can only access EEPROM with
address inputs set to 0.
20.1 Auto Mode EEPROM Access
Using auto mode, PCI 6150 can access the EEPROM on a WORD basis via hardware sequencer. Users need
only to access a WORD data via PCI 6150 configuration registers for EEPROM START control, address,
read/write command. Before each access, software should check the Auto Mode Cycle in Progress status before
issuing the next START.
20.2 EEPROM Mode at Reset
Upon P_RSTIN# going high, PCI 6150 auto-loads input for EEPROM automatic load condition.
The first offset in the EEPROM contains a signature. If the signature is recognized, register auto-load will
commence right after RESET. During the auto-load, PCI 6150 will read sequential words from the EEPROM and
write to the appropriate registers.
Before the PCI 6150 registers can be accessed through host, user should check the auto-load condition by
reading the EEPAUTO bit. Host access is allowed only after EEPAUTO status becomes '0' which means that the
autoload initialization sequence is complete.
PCI 6150 Data Book v2.0
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20.3 EEPROM Data Structure
Following the reset, if the condition above is met, PCI 6150 will auto-load the registers with data from EEPROM.
The following table describes the data structure used in EEPROM.
The PCI 6150 accesses the EEPROM one word at a time. It is important to note that in the data phase, bit orders
are reverse of that of the address phase. PCI 6152 only supports EEPROM Device Address 0.
A
C
K
M
S
B
M
S
B
L
S
B
L
S
B
S
T
O
P
Data (n) Data (n +1)
A
C
K
A
C
K
Word
Address (n)
M
S
B
L
S
B
0
S
T
A
R
T
10
A
C
K
W
R
I
T
E
Device
Address
10 000
10
A
C
K
A
C
K
Word
Address (n)
M
S
B
L
S
B
W
R
I
T
E
Device
Address
0
10 000
S
T
A
R
T
10
A
C
K
R
E
A
D
Device
Address
10 000
A
C
K
M
S
B
M
S
B
L
S
B
L
S
B
Data (n) Data (n +1)
N
O
A
C
K
S
T
O
P
S
T
A
R
T
Read:
Write:
PCI 6150 Data Book v2.0
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20.3.1 EEPROM Address and Corresponding PCI 6150 Register
EEPROM
Byte
Address
PCI
Configuration
Offset
Description
00-01h EEPROM signature: Autoload will only proceed if it reads a value of 1516h on
the first word loaded.
0x1516=valid signature, otherwise disable autoloading
02h Region Enable: Enables or disables certain regions of the PCI configuration
space from being loaded from the EEPROM. Valid combinations are:
Bit 0: Reserved
Bits 4-1: 0000 = stop autoload at offset 03h: Group 1
0001 = stop autoload at offset 13h: Group 2
0011 = stop autoload at offset 23h: Group 3
0111 = stop autoload at offset 27h: Group 4
1111 = autoload all EEPROM loadable registers: Group 5
Other combinations are undefined.
Bits7-5: reserved
03h Enable Miscellaneous functions:
Bit0: ISA Enable Control bit Write Protect: When this bit is set, PCI 6150 will
change the standard PCI-to-PCI Bridge Control Register 3Eh bit 2 into read
only and ISA Enable feature will not be available.
Bit1-7: Reserved
End of Group 1
04-05h 00-01h Vendor ID
06-07h 02-03h Device ID
08h Reserved
09h 09h Class Code: Contains low byte of Class Code Register
0Ah-0Bh 0Ah-0Bh Class Code higher bytes: Contains, upper bytes of Class Code Register
0Ch 0Eh Header Type
0Dh 09h Reserved
0Eh-0Fh 0Ah-0Bh Reserved
10h 0Eh Reserved
11h 0Fh BIST
12h-13h 50h Internal Arbiter Control
End of Group 2
14h 44h Primary flow through control
15h 45h Timeout Control
16h-17h 46-47h Miscellaneous Options
18h 48h Primary Initial Prefetch count
19h 49h Secondary Initial Prefetch count
1Ah 4Ah Primary Incremental Prefetch Count
1Bh 4Bh Secondary Incremental Prefetch Count
1Ch 4Ch Primary Maximum Prefetch Count
1Dh 4Dh Secondary Maximum Prefetch Count
1Eh 4Eh Secondary flow through control
1Fh E3h Power Management Data
20h-21h E0h Power Management CSR
22h- 23h DEh Power management Capabilities
End of Group 3
24-3Fh Reserved (Must be set to 0)
PCI 6150 Data Book v2.0
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21 Vital Product Data
PCI 6150 contains the Vital Product Data (VPD) registers as specified in the PCI Local Bus Specification Revision
2.2.
• The VPD information is stored in the EEPROM device along with the Autoload information.
PCI 6150 provides for storage of 192 bytes of VPD data in the EEPROM device.
• VPD related registers are located starting at offset ECh of the PCI configuration space.
• VPD also uses the enhanced capabilities port address mechanism.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 109
22 PCI Power Management
PCI 6150 incorporates functionality that meets the requirements of the PCI Power Management Specification,
Revision 1.0. These features include:
• PCI power management registers using the enhanced capabilities port (ECP) address mechanism
• Support for D0, D3hot and D3cold power management states
• Support for D0, D1, D2, D3hot and D3cold power management states for devices behind the bridge
• Support of the B2 secondary bus power state when in the D3hot power management state
Table 22-1 below shows the states and related actions that the PCI 6150 performs during power management
transitions. (no other transactions are permitted.)
Table 22-1: States and Related Actions During Power Management Transitions
Current State Next State Action
D0 D3cold
Power has been removed from the PCI 6150. A power-up reset must be
performed to bring the PCI 6150 to D0.
D0 D3hot
If enabled to do so by the BPCCE pin, the PCI 6150 will disable the
secondary clocks and drive them low.
D0 D2 Unimplemented power state. The PCI 6150 will ignore the write to the
power state bits (power state remains at D0).
D0 D1 Unimplemented power state. The PCI 6150 will ignore the write to the
power state bits (power state remains at D0).
D3hot D0
The PCI 6150 enables secondary clock outputs and performs an internal
chip reset. Signal S_RSTOUT# will not be asserted. All registers will be
returned to the reset values and buffers will be cleared.
D3hot D3cold
Power has been removed from the PCI 6150. A power-up reset must be
performed to bring the PCI 6150 to D0.
D3cold D0 Power-up reset. The PCI 6150 performs the standard power-up reset
functions.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 110
23 Hot Swap
In order to use Hot Swap function, both EJECT_EN# and GPIO3FN# must be connected to “0”.
PCI 6150 incorporates functionality that meets the requirements of the CompactPCI Hot Swap specification
PICMG 2.1 R2.0 with High Availability Programming Interface level 1 (PI=1). The CompactPCI Hot Swap register
block is located at PCI configuration offset E4h. Designers should refer to the CompactPCI Hot Swap
specification for detailed implementation guideline.
Important Note:
If Hot Swap feature is not enabled, L_STAT inputs must be connected to logic “0”. ENUM# can be left
unconnected.
PCI 6150 Hot Swap register is located at E6h.
23.1 Hot Swap Signals
PCI 6150 has the following hot swap related pins:
• ENUM#: This is the output signal ENUM# to notify the system host that either a board has been freshly
inserted or is about to be extracted. ENUM# is an open collector signal. ENUM# is asserted if INS or EXT
bit is set and EIM is 0.
• LED: This is the status BLUE LED. LED is illuminated if RSTIN# is asserted. LED is also illuminated when
the LOO bit is asserted and RSTIN# is deasserted. LED is an active HIGH signal that allows other circuit
to drive the BLUE LED.
• EJECT (GPIO3): This is the Handle Switching input. This signal should be debounced by external
hardware and must be connected to logic “0” if hot swap function is not used. This signal can cause the
assertion of ENUM#.
23.2 Device Hiding
PCI 6150 implements Device Hiding to eliminate mid-transaction extractions. PCI 6150 invokes Device Hiding by
hardware upon hot swap after P_RSTIN# becomes inactive and ejector handle is still unlocked.
PCI 6150 will be quiesced by software before Device Hiding is invoked. Current transaction will be completed as
early as possible. PCI 6150 will not initiate a transaction as a master and will not respond as a target to IO
transactions and will not signal interrupts.
When Device Hiding is invoked, PCI 6150 shall terminate current configuration transaction by signaling
Disconnect. Following the completion of the current transaction (which is disconnected), PCI 6150 shall not
respond as a target to any subsequent transactions until Device Hiding is canceled.
If PCI 6150 is not participating in a transaction when Device Hiding is invoked, PCI 6150 shall not respond as a
target to any subsequent transactions until Device Hiding is canceled.
Device Hiding is cancelled when the handle switch is relocked.
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 111
24 Package Specifications
PCI 6150 comes in an industry standard square 208 pin Quad Flat Pack (QFP) package.
This specification outlines the mechanical dimensions for PCI 6150 chip.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
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51
156
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106
54
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52
208
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158
P2
157
53
105
104
W1
W2
W3
P1
H1 H2
N
F
L
D
C
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 112
The following table lists the package dimensions in millimeters.
Symbol Dimension Name Minimum Nominal Maximum
W1
W2 Package width (length) 27.95 28.00 28.05
W3 Package overall width (length) 30.60
P1 Lead pitch 0.50
P2 Lead width 0.17 0.27
C Lead thickness 0.09 0.20
D0.13
H1 Package overall height 4.20
H2 Package thickness 3.17 3.95
L Lead length 1.30
F Foot length 0.45 0.60 0.75
N Foot angle 0 7
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 113
25 Electrical Specifications
25.1 Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.)
Parameter Minimum Maximum
Storage Temperature Range -55 °C 125 °C
Junction Temperature 125 °C
Supply Voltage, VDD 3.9V
Maximum Voltage to signal pins 5.5V
Maximum Power 1.8W
Note: Stresses greater than those listed under MAXIMUM RATINGS may cause permanent damage to
the device. This is a stress rating only and functional operation of the device at these or any conditions
above those indicated in the operational sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
25.2 Functional Operating Range
Parameter Minimum Maximum
Supply Voltage 3.0 V 3.6 V
Operating ambient temperature 0 °C 70 °C
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 114
25.3 DC Electrical Characteristics
Symbol Parameter Condition Min Max Unit Notes
VDD Supply Voltage 3.0 3.6 V
VIO PVIO, SVIO pin Interface I/O Voltage 3.0 5.5 V
Vih Input HIGH Voltage 0.5 VDD VIO V
Vil Input LOW Voltage -0.5 0.3 VDD V
Vol Output LOW Voltage Iiout = 1500 µA0.1 VDD V
Voh Output HIGH Voltage Iiout = -500 µA0.9 VDD V
Iil Input Leakage Current 0 < Vin < VDD ±2 µA
Cin Input Pin Capacitance 7.0 pF
PCI 6150 Data Book v2.0
2003 PLX Technology, Inc. All rights reserved. 115
25.4 PCI Signal Timing Specification
25.4.1 PCI Signal Timing
Symbol Parameter Minimum Maximum Unit
Tval CLK to signal valid delay -
bused signals
28 ns
Tval(ptp) CLK to signal valid delay –
point to point
28 ns
Ton Float to active delay 2 - ns
Toff Active to float delay - 14 ns
Tsu Input setup time to CLK –
bused signals
3- ns
Tsu(ptp) Input setup time to CLK –
point to point
5-
ThInput signal hold time from
CLK
0.5 - ns
