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MULTI -CHIP MO DULE FEATURES
Twelve (12) completely independent
E1 Framers in one small 27 mm x 27 mm
Package
Each Multi-Chip Module (MCM) Contains
Three DS21Q44 Quad E1 Framer Die
Each Quad Framer can be concatenated into
a Single 8.192 MHz Backplane Data Stream
300–pin MCM 1.27 mm pitch BGA package
(27 mm X 27 mm)
Low Power 3.3V CMOS with 5V Tolerant
Input & Outputs
FRAMER FEATURES
All framers are fully independent; transmit
and receive sections of each framer are fully
independent
Frames to FAS, CAS, CCS, and CRC4
formats
Each framer contains dual two–frame elastic
store slip buffers that can connect to
asynchronous backplanes up to 8.192 MHz
8–bit parallel control port that can be used
directly on either multiplexed or non–
multiplexed buses (Intel or Motorola)
Easy access to Si and Sa bits
Extracts and inserts CAS signaling
FUNCTIONAL DIAGRAM
Receive
Framer Elastic
Store
Transmit
Formatter Elastic
Store
FRAMER #1
FRAMER #2
FRAMER #3
Control Port
FRAMER #12
ρρρ
ρρρρρρ
ρρρ
Large counters for bipolar and code
violations, CRC4 code word errors, FAS
word errors, and E-bits
Programmable output clocks for Fractional
E1, per channel loopback, H0 and H12
applications
Integral HDLC controller with 64-byte
buffers. Configurable for Sa bits or DS0
operation
Detects and generates AIS, remote alarm,
and remote multiframe alarms
IEEE 1149.1 support
DESCRIPTION
The DS21FT40 MCM offers a high density packaging arrangement for the DS21Q44 E1 Enhanced Quad
Framer. Three DS21Q44 silicon die are packaged in a Multi-Chip Module (MCM) with the electrical
connections as shown in Figure 1-1. The DS21FT40 is closely related to the DS21FT44. Most of the
functions of the DS21FT44 are available on the DS21FT40. The differences are listed in Table 1-1.
Table 2-1 lists all of the signals on the MCM.
The DS21Q44 E1 Framer is an enhanced version of the DS21Q43 Quad E1 Framer. Each DS21Q44 die
contains four framers that are configured and read through a common microprocessor-compatible parallel
port. Each framer consists of a receive framer, receive elastic store, transmit formatter and transmit
elastic store. All four framers in the DS21Q44 are totally independent, they do not share a common
framing synchronizer. Also, the transmit and receive sides of each framer are totally independent. The
DS21FT40
Four x Three 12 Channel E1 Frame
r
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DS21FT40
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dual two-frame elastic stores contained in each of the four framers can be independently enabled and
disabled as required. The device fully meets all of the latest E1 specifications including CCITT/ITU
G.704, G.706, G.962, and I.431 as well as ETS 300 011 and ETS 300 233.
Functional Descr i pti on
The receive side in each framer locates FAS frame and CRC and CAS multiframe boundaries as well as
detects incoming alarms including, carrier loss, loss of synchronization, AIS and Remote Alarm. If
needed, the receive side elastic store can be enabled in order to absorb the phase and frequency
differences between the recovered E1 data stream and an asynchronous backplane clock which is
provided at the RSYSCLK input. The clock applied at the RSYSCLK input can be either a 2.048 MHz
clock or a 1.544 MHz clock. The RSYSCLK can be a burst clock with speeds up to 8.192 MHz.
The transmit side in each framer is totally independent from the receive side in both the clock
requirements and characteristics. Data off of a backplane can be passed through a transmit side elastic
store if necessary. The transmit formatter will provide the necessary frame/multiframe data overhead for
E1 transmission.
Reader’s Note: This data sheet assumes a particular nomenclature of the E1 operating environment. In
each 125 us frame, there are 32 8–bit timeslots numbered 0 to 31. Timeslot 0 is transmitted first and
received first. These 32 timeslots are also referred to as channels with a numbering scheme of 1 to 32.
Timeslot 0 is identical to channel 1, timeslot 1 is identical to Channel 2, and so on. Each timeslot (or
channel) is made up of 8 bits which are numbered 1 to 8. Bit number 1 is the MSB and is transmitted
first. Bit number 8 is the LSB and is transmitted last. Throughout this data sheet, the following
abbreviations will be used:
FAS Frame Alignment Signal
CAS Channel Associated Signaling
MF Multiframe
Si International bits
CRC4 Cyclical Redundancy Check
CCS Common Channel Signaling
Sa Additional bits
E-bit CRC4 Error Bits
DS21FT40
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DS21FT40 Schematic Figure 1-1
RCLK1/2/3/4
RPOS1/2/3/4
RNEG1/2/3/4
RSER1/2/3/4
RSYNC1/2/3/4
RSYSCLK1/2/3/4
TCLK1/2/3/4
TNEG1/2/3/4
TPOS1/2/3/4
TSER1/2/3/4
TSSYNC1/2/3/4
TSYNC1/2/3/4
TSYSCLK1/2/3/4
TLINK0/1/2/3
INT*
FMS
D0 to D7
A0 to A7
RD*
WR*
BTS
MUX
CS*
FS0/FS1
TEST
Signals N ot Connected &
Left Open Circuited Include:
RLOS/LOTC
RLINK
RLCLK
RCHBLK
RCHCLK
RFSYNC
TLCLK
TCHCLK
TCHBLK
RSIG
TSIG
8MCLK
CLKSI
JTRST*
JTMS
JTCLK
JTDI
JTDO
DS21Q44 # 1
RCLK5/6/7/8
RPOS5/6/7/8
RNEG5/6/7/8
RSER5/6/7/8
RSYNC5/6/7/8
RSYSCLK5/6/7/8
TCLK5/6/7/8
TNEG5/6/7/8
TPOS5/6/7/8
TSER5/6/7/8
TSSYNC5/6/7/8
TSYNC5/6/7/8
TSYSCLK5/6/7/8
INT*
D0 to D7
A0 to A7
RD*
WR*
BTS
MUX
CS*
FS0/FS1
TEST
Signals N ot Connected &
Left Open Circuited Include:
RLOS/LOTC
RLINK
RLCLK
RCHBLK
RCHCLK
RFSYNC
TLCLK
TCHCLK
TCHBLK
RSIG
TSIG
8MCLK
CLKSI
JTRST*
JTMS
JTCLK
JTDI
JTDO
DS21Q44 # 2
2
8
8
See Connecting Page
DVDD
DVSS
DVSS
TLINK0/1/2/3
FMS
DVSS
DVSS DVDD
RMSYNC5/6/7/8
RMSYNC1/2/3/4
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DS21FT40 Schematic Figure 1-1 (continued)
Changes in DS21FT40 compared to DS21FT44 Table 1-1
1. The SYSCLK pins have been separated into TSYSCLK and RSYSCLK pins.
2. RMSYNC pins have been added.
3. FMS tied to Vdd.
4. The following signals are not available:
RSIG / TSIG / 8MCLK / CLKSI / JTRST* / JTMS / JTCLK / JTDI / JTDO
RCLK9/10/11/12
RPOS9/10/11/12
RNEG9/10/11/12
RSER9/10/11/12
RSYNC9/10/11/12
RSYSCLK9/10/11/12
TCLK9/10/11/12
TNEG9/10/11/12
TPOS9/10/11/12
TSER9/10/11/12
TSSYNC9/10/11/12
TSYNC9/10/11/12
TSYSCLK9/10/11/12
TLINK0/1/2/3
INT*
FMS
D0 to D7
A0 to A7
RD*
WR*
BTS
MUX
CS*
FS0/FS1
TEST
Signals Not Connected &
Left Open Circuited Include:
RLOS/LOTC
RLINK
RLCLK
RCHBLK
RCHCLK
RFSYNC
TLCLK
TCHCLK
TCHBLK
RSIG
TSIG
8MCLK
CLKSI
JTRST*
JTMS
JTCLK
JTDI
JTDO
DS21Q44 # 3 DVDD
DVSS
DVSS
See Connecting Page
RMSYNC9/10/11/12
DS21FT40
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DS21FT40 ENHANCED 12-Channel E1 FRAMER Figure 1-2
VSS
VDD
FRAMER #2
FRAMER #3
FRAMER #1
Parallel & Test Co nt r ol Port
(routed to all blocks)
D0 to D7 /
AD0 to AD7
FS1 BTS INT*
WR*
(R/W*) RD*
(DS*)
FS0CS*TEST ALE
(AS)/
A6
A0 to A5 ,
A7 MUX
78
Framer Loopback
AIS Generation
HDB3 Encode
CRC4 Generation
FAS Word Insertion
Receive Side Framer
Transmit Side Formatter
BPV Counter
Alarm Detection
Per-Channel Code Insert
Elastic
Store
E-BIT Counter
sync
data
clock
sync
data
clock
TSYNC
TCLK
TSER
RMSYNC
TSSYNC
TSYSCLK
RSER
RSYSCLK
RSYNC
Sa Extraction
Timing Control
Elastic
Store
Sync Control
Timing Control
HDB3 Decoder
Synchronizer
CRC Error Counter
FAS Error Counter
Signaling Extraction
SA and SI Extraction
Signaling
Buffer
Hardware
Signaling
Insertion
Remote Loopback
Per-Channel Code Insert
Per-Channel Loopback
64-Byte Buffer
RPOS
RCLK
RNEG
TPOS
TNEG
HDLC Engine
DS0 Insertion
Power
LOTC DET
&
MUX
Sa Insertion
64-Byte Buffer
HDLC Engine
DS0 Insertion
SI Bit Insertion
E-Bit Insertion
SA Insertion
Signaling Insertion
FRAMER #12
DS21FT40
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TABLE OF CONTENTS
DESCRIPTION..........................................................................................................................................................................1
1. DS21FT40 PIN DESCRIPTION.......................................................................................................................................8
2. DS21FT44 PIN FUNCTION DESCRIPTION...............................................................................................................16
3. DS21FT40 REGISTER MAP..........................................................................................................................................19
4. PARALLEL PORT..........................................................................................................................................................24
5. CONTROL, ID AND TEST REGISTERS.....................................................................................................................24
6. STATUS AND INFORMATION REGISTERS............................................................................................................33
7. ERROR COUNT REGISTERS......................................................................................................................................39
8. DS0 MONITORING FUNCTION..................................................................................................................................41
9. SIGNALING OPERATION............................................................................................................................................44
9.1 PROCESSOR BASED SIGNALING........................................................................................................................44
9.2 HARDWARE BASED SIGNALING........................................................................................................................47
10. PER–CHANNEL CODE GENERATION AND LOOPBACK................................................................................47
10.1 TRANSMIT SIDE CODE GENERATION...............................................................................................................47
10.1.1 Simple Idle Code Insertion and Per–Channel Loopback...................................................................................47
10.1.2 Per–Channel Code Insertion .............................................................................................................................48
10.2 RECEIVE SIDE CODE GENERATION ..................................................................................................................49
11. CLOCK BLOCKING REGISTERS ..........................................................................................................................50
12. ELASTIC STORES OPERATION ............................................................................................................................50
12.1 RECEIVE SIDE.........................................................................................................................................................51
12.2 TRANSMIT SIDE.............................................................................................................. .......................................51
13. ADDITIONAL (SA) AND INTERNATIONAL (SI) BIT OPERATION ................................................................51
13.1 INTERNAL REGISTER SCHEME BASED ON DOUBLE–FRAME.....................................................................51
13.2 INTERNAL REGISTER SCHEME BASED ON CRC4 MULTIFRAME................................................................5 3
14. HDLC CONTROLLER FOR THE SA B ITS OR DS0...................................................................................... .......55
14.1 GENERAL OVERVIEW..................................................................................................................................................55
14.2 HDLC STATUS REGISTERS.........................................................................................................................................56
14.3 BASIC OPERATION DETAILS........................................................................................................................................57
14.4 HDLC REGISTER DESCRIPTION ..................................................................................................................................58
15. INTERLEAVED PCM BUS OPERATION ..............................................................................................................64
16. TIMING DIAGRAMS.................................................................................................................................................67
17. OPERATING PARAMETERS...................................................................................................................................75
18. DS21FT40 MECHANICAL DIMENSIONS..............................................................................................................86
DS21FT40
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DOCUMENT REVISION HISTORY
Revision Notes
5-18-99 Initial Release
8-19-99 Concatenated DS21FT40 and DS21Q44 data sheets
8-26-99 Remove RCHBLK pins.
2-17-00 Corrected error in Figure 1-1 (removed RCHBLK pins).
DS21FT40
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1. DS21FT40 PIN DESCRIPTION
Pin Description Sorted by Pin Number Table 2-1
Lead Symbols I/O Description
G20 A0 I Address Bus Bit 0 (lsb).
H20 A1 I Address Bus Bit 1.
G19 A2 I Address Bus Bit 2.
H19 A3 I Address Bus Bit 3.
G18 A4 I Address Bus Bit 4.
H18 A5 I Address Bus Bit 5.
G17 A6 I Address Bus Bit 6.
H17 A7 I Address Bus Bit 7 (msb).
W15 BTS I Bus Timing Select. 0 = Intel / 1 = Motorola.
T8 CS1* I Chip Select for Quad Framer 1.
Y4 CS2* I Chip Select for Quad Framer 2.
Y15 CS3* I Chip Select for Quad Framer 3.
L20 D0 I/O Data Bus Bit 0 (lsb).
M20 D1 I/O Data Bus Bit 1.
L19 D2 I/O Data Bus Bit 2.
M19 D3 I/O Data Bus Bit 3.
L18 D4 I/O Data Bus Bit 4.
M18 D5 I/O Data Bus Bit 5.
L17 D6 I/O Data Bus Bit 6.
M17 D7 I/O Data Bus Bit 7 (msb).
C7 DVDD1 Digital Positive Supply for Framer 1.
E4 DVDD1 Digital Positive Supply for Framer 1.
D2 DVDD1 Digital Positive Supply for Framer 1.
K3 DVDD2 Digital Positive Supply for Framer 2.
U7 DVDD2 Digital Positive Supply for Framer 2.
P2 DVDD2 Digital Positive Supply for Framer 2.
V19 DVDD3 Digital Positive Supply for Framer 3.
T12 DVDD3 Digital Positive Supply for Framer 3.
L16 DVDD3 Digital Positive Supply for Framer 3.
E9 DVSS1 Digital Signal Ground for Framer 1.
A6 DVSS1 Digital Signal Ground for Framer 1.
D5 DVSS1 Digital Signal Ground for Framer 1.
U3 DVSS2 Digital Signal Ground for Framer 2.
K4 DVSS2 Digital Signal Ground for Framer 2.
U8 DVSS2 Digital Signal Ground for Framer 2.
U4 DVSS3 Digital Signal Ground for Framer 3.
R16 DVSS3 Digital Signal Ground for Framer 3.
Y20 DVSS3 Digital Signal Ground for Framer 3.
Y14 FS0 I Framer Select 0 for the Parallel Control Port.
W14 FS1 I Framer Select 1 for the Parallel Control Port.
G16 INT* O Interrupt for all four Quad Framers.
P17 MUX I Bus Operation Select. 0 = non-multiplexed bus / 1 =
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Lead Symbols I/O Description
multiplexed bus
A2 RCLK1 I Receive Clock for Framer 1
K1 RCLK2 I Receive Clock for Framer 2.
D10 RCLK3 I Receive Clock for Framer 3.
B9 RCLK4 I Receive Clock for Framer 4.
M3 RCLK5 I Receive Clock for Framer 5.
V1 RCLK6 I Receive Clock for Framer 6.
W6 RCLK7 I Receive Clock for Framer 7.
J3 RCLK8 I Receive Clock for Framer 8.
T9 RCLK9 I Receive Clock for Framer 9.
W10 RCLK10 I Receive Clock for Framer 10.
Y18 RCLK11 I Receive Clock for Framer 11.
N17 RCLK12 I Receive Clock for Framer 12.
E18 RD* I Read Input.
D3 RMSYNC1 O Receive Multiframe Sync from Framer 1
G2 RMSYNC2 O Receive Multiframe Sync from Framer 2
D4 RMSYNC3 O Receive Multiframe Sync from Framer 3
D8 RMSYNC4 O Receive Multiframe Sync from Framer 4
N2 RMSYNC5 O Receive Multiframe Sync from Framer 5
V4 RMSYNC6 O Receive Multiframe Sync from Framer 6
V6 RMSYNC7 O Receive Multiframe Sync from Framer 7
K5 RMSYNC8 O Receive Multiframe Sync from Framer 8
U10 RMSYNC9 O Receive Multiframe Sync from Framer 9
Y11 RMSYNC10 O Receive Multiframe Sync from Framer 10
W19 RMSYNC11 O Receive Multiframe Sync from Framer 11
U20 RMSYNC12 O Receive Multiframe Sync from Framer 12
B2 RNEG1 I Receive Negative Data for Framer 1.
H2 RNEG2 I Receive Negative Data for Framer 2.
D9 RNEG3 I Receive Negative Data for Framer 3.
A9 RNEG4 I Receive Negative Data for Framer 4.
M2 RNEG5 I Receive Negative Data for Framer 5.
V3 RNEG6 I Receive Negative Data for Framer 6.
V7 RNEG7 I Receive Negative Data for Framer 7.
P3 RNEG8 I Receive Negative Data for Framer 8.
U9 RNEG9 I Receive Negative Data for Framer 9.
W11 RNEG10 I Receive Negative Data for Framer 10.
W17 RNEG11 I Receive Negative Data for Framer 11.
T20 RNEG12 I Receive Negative Data for Framer 12.
A1 RPOS1 I Receive Positive Data for Framer 1.
H1 RPOS2 I Receive Positive Data for Framer 2.
H4 RPOS3 I Receive Positive Data for Framer 3.
C9 RPOS4 I Receive Positive Data for Framer 4.
M1 RPOS5 I Receive Positive Data for Framer 5.
W2 RPOS6 I Receive Positive Data for Framer 6.
V5 RPOS7 I Receive Positive Data for Framer 7.
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Lead Symbols I/O Description
P4 RPOS8 I Receive Positive Data for Framer 8.
T10 RPOS9 I Receive Positive Data for Framer 9.
V11 RPOS10 I Receive Positive Data for Framer 10.
Y19 RPOS11 I Receive Positive Data for Framer 11.
R19 RPOS12 I Receive Positive Data for Framer 12.
C1 RSER1 O Receive Serial Data from Framer 1.
H3 RSER2 O Receive Serial Data from Framer 2.
C6 RSER3 O Receive Serial Data from Framer 3.
C8 RSER4 O Receive Serial Data from Framer 4.
P1 RSER5 O Receive Serial Data from Framer 5.
W4 RSER6 O Receive Serial Data from Framer 6.
T7 RSER7 O Receive Serial Data from Framer 7.
N4 RSER8 O Receive Serial Data from Framer 8.
U11 RSER9 O Receive Serial Data from Framer 9.
Y12 RSER10 O Receive Serial Data from Framer 10.
V16 RSER11 O Receive Serial Data from Framer 11.
T16 RSER12 O Receive Serial Data from Framer 12.
B1 RSYNC1 I/O Receive Frame/Multiframe Sync for Framer 1.
G1 RSYNC2 I/O Receive Frame/Multiframe Sync for Framer 2.
D6 RSYNC3 I/O Receive Frame/Multiframe Sync for Framer 3.
A7 RSYNC4 I/O Receive Frame/Multiframe Sync for Framer 4.
N3 RSYNC5 I/O Receive Frame/Multiframe Sync for Framer 5.
Y2 RSYNC6 I/O Receive Frame/Multiframe Sync for Framer 6.
U5 RSYNC7 I/O Receive Frame/Multiframe Sync for Framer 7.
J4 RSYNC8 I/O Receive Frame/Multiframe Sync for Framer 8.
T11 RSYNC9 I/O Receive Frame/Multiframe Sync for Framer 9.
V13 RSYNC10 I/O Receive Frame/Multiframe Sync for Framer 10.
V15 RSYNC11 I/O Receive Frame/Multiframe Sync for Framer 11.
P18 RSYNC12 I/O Receive Frame/Multiframe Sync for Framer 12.
B5 RSYSCLK1 I Receive System Clock for Framer 1.
E2 RSYSCLK2 I Receive System Clock for Framer 2.
E5 RSYSCLK3 I Receive System Clock for Framer 3.
B8 RSYSCLK4 I Receive System Clock for Framer 4.
M4 RSYSCLK5 I Receive System Clock for Framer 5.
T2 RSYSCLK6 I Receive System Clock for Framer 6.
Y5 RSYSCLK7 I Receive System Clock for Framer 7.
W3 RSYSCLK8 I Receive System Clock for Framer 8.
T4 RSYSCLK9 I Receive System Clock for Framer 9.
Y9 RSYSCLK10 I Receive System Clock for Framer 10.
U12 RSYSCLK11 I Receive System Clock for Framer 11.
R17 RSYSCLK12 I Receive System Clock for Framer 12.
D1 TCLK1 I Transmit Clock for Framer 1.
H5 TCLK2 I Transmit Clock for Framer 2.
C5 TCLK3 I Transmit Clock for Framer 3.
A5 TCLK4 I Transmit Clock for Framer 4.
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Lead Symbols I/O Description
R1 TCLK5 I Transmit Clock for Framer 5.
Y3 TCLK6 I Transmit Clock for Framer 6.
T6 TCLK7 I Transmit Clock for Framer 7.
K2 TCLK8 I Transmit Clock for Framer 8.
U13 TCLK9 I Transmit Clock for Framer 9.
Y13 TCLK10 I Transmit Clock for Framer 10.
T18 TCLK11 I Transmit Clock for Framer 11.
P16 TCLK12 I Transmit Clock for Framer 12.
A13 TEST I Tri-State. 0 = do not tri-state / 1 = tri-state all outputs & I/O
signals
C3 TNEG1 O Transmit Negative Data from Framer 1.
J1 TNEG2 O Transmit Negative Data from Framer 2.
F5 TNEG3 O Transmit Negative Data from Framer 3.
A10 TNEG4 O Transmit Negative Data from Framer 4.
L1 TNEG5 O Transmit Negative Data from Framer 5.
V2 TNEG6 O Transmit Negative Data from Framer 6.
V8 TNEG7 O Transmit Negative Data from Framer 7.
P5 TNEG8 O Transmit Negative Data from Framer 8.
U14 TNEG9 O Transmit Negative Data from Framer 9.
V12 TNEG10 O Transmit Negative Data from Framer 10.
W18 TNEG11 O Transmit Negative Data from Framer 11.
T19 TNEG12 O Transmit Negative Data from Framer 12.
B3 TPOS1 O Transmit Positive Data from Framer 1.
J2 TPOS2 O Transmit Positive Data from Framer 2.
J5 TPOS3 O Transmit Positive Data from Framer 3.
B10 TPOS4 O Transmit Positive Data from Framer 4.
L2 TPOS5 O Transmit Positive Data from Framer 5.
W1 TPOS6 O Transmit Positive Data from Framer 6.
W7 TPOS7 O Transmit Positive Data from Framer 7.
R3 TPOS8 O Transmit Positive Data from Framer 8.
T14 TPOS9 O Transmit Positive Data from Framer 9.
Y10 TPOS10 O Transmit Positive Data from Framer 10.
V18 TPOS11 O Transmit Positive Data from Framer 11.
V20 TPOS12 O Transmit Positive Data from Framer 12.
B4 TSER1 I Transmit Serial Data for Framer 1.
E1 TSER2 I Transmit Serial Data for Framer 2.
F3 TSER3 I Transmit Serial Data for Framer 3.
D7 TSER4 I Transmit Serial Data for Framer 4.
L5 TSER5 I Transmit Serial Data for Framer 5.
T1 TSER6 I Transmit Serial Data for Framer 6.
Y6 TSER7 I Transmit Serial Data for Framer 7.
T3 TSER8 I Transmit Serial Data for Framer 8.
M16 TSER9 I Transmit Serial Data for Framer 9.
W9 TSER10 I Transmit Serial Data for Framer 10.
W16 TSER11 I Transmit Serial Data for Framer 11.
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Lead Symbols I/O Description
W20 TSER12 I Transmit Serial Data for Framer 12.
A3 TSSYNC1 I Transmit System Sync for Framer 1.
F2 TSSYNC2 I Transmit System Sync for Framer 2.
G5 TSSYNC3 I Transmit System Sync for Framer 3.
E8 TSSYNC4 I Transmit System Sync for Framer 4.
L4 TSSYNC5 I Transmit System Sync for Framer 5.
U1 TSSYNC6 I Transmit System Sync for Framer 6.
Y7 TSSYNC7 I Transmit System Sync for Framer 7.
R4 TSSYNC8 I Transmit System Sync for Framer 8.
T15 TSSYNC9 I Transmit System Sync for Framer 9.
W8 TSSYNC10 I Transmit System Sync for Framer 10.
Y17 TSSYNC11 I Transmit System Sync for Framer 11.
U19 TSSYNC12 I Transmit System Sync for Framer 12.
E3 TSYNC1 I/O Transmit Sync for Framer 1.
F4 TSYNC2 I/O Transmit Sync for Framer 2.
E7 TSYNC3 I/O Transmit Sync for Framer 3.
A4 TSYNC4 I/O Transmit Sync for Framer 4.
R2 TSYNC5 I/O Transmit Sync for Framer 5.
W5 TSYNC6 I/O Transmit Sync for Framer 6.
T5 TSYNC7 I/O Transmit Sync for Framer 7.
M5 TSYNC8 I/O Transmit Sync for Framer 8.
T13 TSYNC9 I/O Transmit Sync for Framer 9.
W13 TSYNC10 I/O Transmit Sync for Framer 10.
U16 TSYNC11 I/O Transmit Sync for Framer 11.
N16 TSYNC12 I/O Transmit Sync for Framer 12.
C4 TSYSCLK1 I Transmit System Clock for Framer 1.
F1 TSYSCLK2 I Transmit System Clock for Framer 2.
G4 TSYSCLK3 I Transmit System Clock for Framer 3.
C10 TSYSCLK4 I Transmit System Clock for Framer 4.
L3 TSYSCLK5 I Transmit System Clock for Framer 5.
U2 TSYSCLK6 I Transmit System Clock for Framer 6.
V9 TSYSCLK7 I Transmit System Clock for Framer 7.
R5 TSYSCLK8 I Transmit System Clock for Framer 8.
U15 TSYSCLK9 I Transmit System Clock for Framer 9.
V10 TSYSCLK10 I Transmit System Clock for Framer 10.
U18 TSYSCLK11 I Transmit System Clock for Framer 11.
R18 TSYSCLK12 I Transmit System Clock for Framer 12.
Y16 WR* I Write Input.
A11 NC No Connect
A12 NC No Connect
A14 NC No Connect
A15 NC No Connect
A16 NC No Connect
A17 NC No Connect
A18 NC No Connect
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Lead Symbols I/O Description
A19 NC No Connect
A20 NC No Connect
A8 NC No Connect
B11 NC No Connect
B12 NC No Connect
B13 NC No Connect
B14 NC No Connect
B15 NC No Connect
B16 NC No Connect
B17 NC No Connect
B18 NC No Connect
B19 NC No Connect
B20 NC No Connect
B6 NC No Connect
B7 NC No Connect
C11 NC No Connect
C12 NC No Connect
C13 NC No Connect
C14 NC No Connect
C15 NC No Connect
C16 NC No Connect
C17 NC No Connect
C18 NC No Connect
C19 NC No Connect
C2 NC No Connect
C20 NC No Connect
D11 NC No Connect
D12 NC No Connect
D13 NC No Connect
D14 NC No Connect
D15 NC No Connect
D16 NC No Connect
D17 NC No Connect
D18 NC No Connect
D19 NC No Connect
D20 NC No Connect
E10 NC No Connect
E11 NC No Connect
E12 NC No Connect
E13 NC No Connect
E14 NC No Connect
E15 NC No Connect
E16 NC No Connect
E17 NC No Connect
E19 NC No Connect
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Lead Symbols I/O Description
E20 NC No Connect
E6 NC No Connect
F16 NC No Connect
F17 NC No Connect
F18 NC No Connect
F19 NC No Connect
F20 NC No Connect
G3 NC No Connect
H16 NC No Connect
J16 NC No Connect
J17 NC No Connect
J18 NC No Connect
J19 NC No Connect
J20 NC No Connect
K16 NC No Connect
K17 NC No Connect
K18 NC No Connect
K19 NC No Connect
K20 NC No Connect
N1 NC No Connect
N18 NC No Connect
N19 NC No Connect
N20 NC No Connect
N5 NC No Connect
P19 NC No Connect
P20 NC No Connect
R20 NC No Connect
T17 NC No Connect
U17 NC No Connect
U6 NC No Connect
V14 NC No Connect
V17 NC No Connect
W12 NC No Connect
Y1 NC No Connect
Y8 NC No Connect
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DS21FT40 PCB Land Pattern Figure 2-1
The diagram shown below is the lead pattern that will be placed on the target PCB. This is the same
pattern that would be seen as viewed through the MCM from the top.
1234567891011121314151617181920
Arpos
1rclk
1ts
sync1 tsync
4tclk
4dvss
1rsync
4nc rneg
4tneg
4nc nc test ns ns nc nc nc nc nc
Brsync
1rneg
1tpos
1tser
1rsys
clk
1
nc nc rsys
clk
4
rclk
4tpos
4nc nc nc nc nc nc nc nc nc nc
Crser
1nc tneg
1tsys
clk
1
tclk
3rser
3dvdd
1rser4 rpos
4tsys
clk
4
nc nc nc nc ns nc nc nc nc nc
Dtclk
1dvdd
1rm
sync
1
rm
sync
3
dvss
1rsync
3tser
4rm
sync4 rneg
3rclk
3nc nc nc nc nc nc nc nc nc nc
Etser
2rsys
clk
2
tsync
1dvdd
1rsys
clk
3
nc tsync
3ts
sync
4
dvss
1nc nc nc nc nc nc nc nc rd* nc nc
Ftsys
clk
2
ts
sync
2
tser
3tsync
2tneg
3nc nc nc nc nc
Grsync
2rm
sync
2
nc tsys
clk
3
ts
sync
3
int* A6 A4 A2 A0
Hrpos
2rneg
2rser
2rpos
3tclk
2nc A7 A5 A3 A1
Jtneg
2tpos
2rclk
8rsync
8tpos
3nc nc nc nc nc
Krclk
2tclk
8dvdd
2dvss
2rm
sync
8
nc nc nc nc nc
Ltneg
5tpos
5tsys
clk
5
ts
sync
5
tser
5dvdd
3D6 D4 D2 D0
Mrpos
5rneg
5rclk
5rsys
clk
5
tsync
8tser
9D7 D5 D3 D1
Nnc rm
sync
5
rsync
5rser
8nc tsync
12 rclk
12 nc nc nc
Prser
5dvdd
2rneg
8rpos
8tneg
8tclk
12 mux rsync
12 nc nc
Rtclk
5tsync
5tpos
8ts
sync
8
tsys
clk
8
dvss
3rsys
clk
12
tsys
clk
12
rpos
12 nc
Ttser
6rsys
clk
6
tser
8rsys
clk
9
tsync
7tclk
7rser
7cs1* rclk
9rpos
9rsync
9dvdd
3tsync
9tpos
9ts
sync
9
rser
12 nc tclk
11 tneg
12 rneg
12
Uts
sync
6
tsys
clk
6
dvss
2dvss
3rsync
7nc dvdd
2dvss
2rneg
9rm
sync
9
rser
9rsys
clk
11
tclk
9tneg
9tsys
clk
9
tsync
11 nc tsys
clk
11
ts
sync
12
rm
sync
12
Vrclk
6tneg
6rneg
6rm
sync
6
rpos
7rm
sync
7
rneg
7tneg
7tsys
clk
7
tsys
clk
10
rpos
10 tneg
10 rsync
10 nc rsync
11 rser
11 nc tpos
11 dvdd
3tpos
12
Wtpos
6rpos
6rsys
clk
8
rser
6tsync
6rclk
7tpos
7ts
sync
10
tser
10 rclk
10 rneg
10 nc tsync
10 fs1 bts tser
11 rneg
11 tneg
11 rm
sync
11
tser
12
Ync rsync
6tclk
6cs2* rsys
clk
7
tser
7ts
sync
7
nc rsys
clk
10
tpos
10 rm
sync
10
rser
10 tclk
10 fs0 cs3* wr* ts
sync
11
rclk
11 rpos
11 dvss
3
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2. DS21FT44 PI N FUNCTI O N DESCRI PTION
TRANSMIT SIDE PINS
Signal Name: TCLK
Signal Description: Transmit Clock
Signal Type: Input
A 2.048 MHz primary clock. Used to clock data through the transmit side formatter.
Signal Name: TSER
Signal Description: Transmit Serial Data
Signal Type: Input
Transmit NRZ serial data. Sampled on the falling edge of TCLK when the transmit side elastic store is
disabled. Sampled on the falling edge of TSYSCLK when the transmit side elastic store is enabled.
Signal Name: TSYSCLK
Signal Description: Transmit System Clock
Signal Type: Input
1.544 MHz or 2.048 MHz clock. Only used when the transmit side elastic store function is enabled.
Should be tied low in applications that do not use the transmit side elastic store. Can be burst at rates up
to 8.192 MHz.
Signal Name: TSYNC
Signal Description: Transmit Sync
Signal Type: Input /Output
A pulse at this pin will establish either frame or multiframe boundaries for the transmit side. This pin can
also be programmed to output either a frame or multiframe pulse. Always synchronous with TCLK.
Signal Name: TSSYNC
Signal Description: Transmit System Sync
Signal Type: Input
Only used when the transmit side elastic store is enabled. A pulse at this pin will establish either frame or
multiframe boundaries for the transmit side. Should be tied low in applications that do not use the
transmit side elastic store. Always synchronous with TSYSCLK.
Signal Name: TPOS
Signal Description: Transmit Positive Data Output
Signal Type: Output
Updated on the rising edge of TCLK with the bipolar data out of the transmit side formatter. Can be
programmed to source NRZ data via the Output Data Format (TCR1.7) control bit.
Signal Name: TNEG
Signal Description: Transmit Negative Data Output
Signal Type: Output
Updated on the rising edge of TCLK with the bipolar data out of the transmit side formatter.
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RECEIVE SIDE PINS
Signal Name: RCLK
Signal Description: Receive Clock Input
Signal Type: Input
2.048 MHz clock that is used to clock data through the receive side framer.
Signal Name: RSER
Signal Description: Receive Serial Data
Signal Type: Output
Received NRZ serial data. Updated on rising edges of RCLK when the receive side elastic store is
disabled. Updated on the rising edges of RSYSCLK when the receive side elastic store is enabled.
Signal Name: RSYNC
Signal Description: Receive Sync
Signal Type: Input /Output
An extracted pulse, one RCLK wide, is output at this pin which identifies either frame or CAS/CRC
multiframe boundaries. If the receive side elastic store is enabled, then this pin can be enabled to be an
input at which a frame or multiframe boundary pulse synchronous with RSYSCLK is applied.
Signal Name: RMSYNC
Signal Description: Receive Multiframe Sync
Signal Type: Output
An extracted pulse, one RSYSCLK wide, is output at this pin which identifies multiframe boundaries. If
the receive side elastic store is disabled, then this output will output multiframe boundaries associated
with RCLK.
Signal Name: RSYSCLK
Signal Description: Receive System Clock
Signal Type: Input
1.544 MHz or 2.048 MHz clock. Only used when the elastic store function is enabled. Should be tied
low in applications that do not use the elastic store. Can be burst at rates up to 8.192 MHz.
Signal Name: RPOS
Signal Description: Receive Positive Data Input
Signal Type: Input
Sampled on the falling edge of RCLK for data to be clocked through the receive side framer. RPOS and
RNEG can be tied together for an NRZ interface. Connecting RPOS to RNEG disables the bipolar
violation monitoring circuitry.
Signal Name: RNEG
Signal Description: Receive Negative Data Input
Signal Type: Input
Sampled on the falling edge of RCLK for data to be clocked through the receive side framer. RPOS and
RNEG can be tied together for an NRZ interface. Connecting RPOS to RNEG disables the bipolar
violation monitoring circuitry.
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PARALLEL CONTROL PORT PINS
Signal Name: INT*
Signal Description: Interrupt
Signal Type: Output
Flags host controller during conditions and change of conditions defined in the Status Registers 1 and 2
and the FDL Status Register. Active low, open drain output.
Signal Name: MUX
Signal Description: Bus Operation
Signal Type: Input
Set low to select non–multiplexed bus operation. Set high to select multiplexed bus operation.
Signal Name: D0 TO D7 / AD0 TO AD7
Signal Description: Data Bus or Address/Data Bus
Signal Type: Input /Output
In non–multiplexed bus operation (MUX = 0), serves as the data bus. In multiplexed bus operation
(MUX = 1), serves as a 8–bit multiplexed address / data bus.
Signal Name: A0 TO A5, A7
Signal Description: Address Bus
Signal Type: Input
In non–multiplexed bus operation (MUX = 0), serves as the address bus. In multiplexed bus operation
(MUX = 1), these pins are not used and should be tied low.
Signal Name: ALE (AS) / A6
Signal Description: Address Latch Enable (Address Strobe) or A6
Signal Type: Input
In non–multiplexed bus operation (MUX = 0), serves as address bit 6. In multiplexed bus operation
(MUX = 1), serves to demultiplex the bus on a positive–going edge.
Signal Name: BTS
Signal Description: Bus Type Select
Signal Type: Input
Strap high to select Motorola bus timing; strap low to select Intel bus timing. This pin controls the
function of the RD*(DS*), ALE(AS), and WR*(R/W*) pins. If BTS = 1, then these pins assume the
function listed in parenthesis ().
Signal Name: RD* (DS)
Signal Description: Read Input (Data Strobe)
Signal Type: Input
RD* is an active low signal and DS is an active high signal.
Signal Name: FS0 AND FS1
Signal Description: Framer Selects
Signal Type: Input
Selects which of the four framers is to be accessed for a specific DS21Q44 die.
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Signal Name: CS1* TO CS3*
Signal Description: Chip Select
Signal Type: Input
Must be low to read or write to a specific DS21Q44 die. These are active low signals.
Signal Name: WR* (R/W*)
Signal Description: Write Input (Read/Write)
Signal Type: Input
WR* is an active low signal.
TEST ACCESS PORT PINS
Signal Name: TEST
Signal Description: 3–State Control
Signal Type: Input
Set high to 3–state all output and I/O pins (including the parallel control port). Set low for normal
operation. Useful in board level testing.
SUPPLY PINS
Signal Name: VDD
Signal Description: Positive Supply
Signal Type: Supply
2.97 to 3.63 volts.
Signal Name: VSS
Signal Description: Signal Ground
Signal Type: Supply
0.0 volts.
3. DS21FT40 REGISTER M AP
Register Map for Each Quad Framer Sorted by Address Table 3-1
ADDRESS R/W REGISTER NAME REGISTER
ABBREVIATION
00 R BPV or Code Violation Count 1 VCR1
01 R BPV or Code Violation Count 2 VCR2
02 R CRC4 Error Count 1 / FAS Error Count 1 CRCCR1
03 R CRC4 Error Count 2 CRCCR2
04 R E-Bit Count 1 / FAS Error Count 2 EBCR1
05 R E-Bit Count 2 EBCR2
06 R/W Status 1 SR1
07 R/W Status 2 SR2
08 R/W Receive Information RIR
09 R/W Test 2 TEST2 (set to 00h)
0A Not used (set to 00H)
0B Not used (set to 00H)
0C Not used (set to 00H)
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ADDRESS R/W REGISTER NAME REGISTER
ABBREVIATION
0D Not used (set to 00H)
0E Not used (set to 00H)
0F R Device ID IDR
10 R/W Receive Control 1 RCR1
11 R/W Receive Control 2 RCR2
12 R/W Transmit Control 1 TCR1
13 R/W Transmit Control 2 TCR2
14 R/W Common Control 1 CCR1
15 R/W Test 1 TEST1 (set to 00h)
16 R/W Interrupt Mask 1 IMR1
17 R/W Interrupt Mask 2 IMR2
18 Not used (set to 00H)
19 Not used (set to 00H)
1A R/W Common Control 2 CCR2
1B R/W Common Control 3 CCR3
1C R/W Transmit Sa Bit Control TSaCR
1D R/W Common Control 6 CCR6
1E R Synchronizer Status SSR
1F R Receive Non-Align Frame RNAF
20 R/W Transmit Align Frame TAF
21 R/W Transmit Non-Align Frame TNAF
22 R/W Transmit Channel Blocking 1
(Not applicable to DS21FT40 – write to
00H.)
TCBR1
23 R/W Transmit Channel Blocking 2
(Not applicable to DS21FT40 – write to
00H.)
TCBR2
24 R/W Transmit Channel Blocking 3
(Not applicable to DS21FT40 – write to
00H.)
TCBR3
25 R/W Transmit Channel Blocking 4
(Not applicable to DS21FT40 – write to
00H.)
TCBR4
26 R/W Transmit Idle 1 TIR1
27 R/W Transmit Idle 2 TIR2
28 R/W Transmit Idle 3 TIR3
29 R/W Transmit Idle 4 TIR4
2A R/W Transmit Idle Definition TIDR
2B R/W Receive Channel Blocking 1 RCBR1
2C R/W Receive Channel Blocking 2 RCBR2
2D R/W Receive Channel Blocking 3 RCBR3
2E R/W Receive Channel Blocking 4 RCBR4
2F R Receive Align Frame RAF
30 R Receive Signaling 1 RS1
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ADDRESS R/W REGISTER NAME REGISTER
ABBREVIATION
31 R Receive Signaling 2 RS2
32 R Receive Signaling 3 RS3
33 R Receive Signaling 4 RS4
34 R Receive Signaling 5 RS5
35 R Receive Signaling 6 RS6
36 R Receive Signaling 7 RS7
37 R Receive Signaling 8 RS8
38 R Receive Signaling 9 RS9
39 R Receive Signaling 10 RS10
3A R Receive Signaling 11 RS11
3B R Receive Signaling 12 RS12
3C R Receive Signaling 13 RS13
3D R Receive Signaling 14 RS14
3E R Receive Signaling 15 RS15
3F R Receive Signaling 16 RS16
40 R/W Transmit Signaling 1 TS1
41 R/W Transmit Signaling 2 TS2
42 R/W Transmit Signaling 3 TS3
43 R/W Transmit Signaling 4 TS4
44 R/W Transmit Signaling 5 TS5
45 R/W Transmit Signaling 6 TS6
46 R/W Transmit Signaling 7 TS7
47 R/W Transmit Signaling 8 TS8
48 R/W Transmit Signaling 9 TS9
49 R/W Transmit Signaling 10 TS10
4A R/W Transmit Signaling 11 TS11
4B R/W Transmit Signaling 12 TS12
4C R/W Transmit Signaling 13 TS13
4D R/W Transmit Signaling 14 TS14
4E R/W Transmit Signaling 15 TS15
4F R/W Transmit Signaling 16 TS16
50 R/W Transmit Si Bits Align Frame TSiAF
51 R/W Transmit Si Bits Non-Align Frame TSiNAF
52 R/W Transmit Remote Alarm Bits TRA
53 R/W Transmit Sa4 Bits TSa4
54 R/W Transmit Sa5 Bits TSa5
55 R/W Transmit Sa6 Bits TSa6
56 R/W Transmit Sa7 Bits TSa7
57 R/W Transmit Sa8 Bits TSa8
58 R Receive Si bits Align Frame RSiAF
59 R Receive Si bits Non-Align Frame RSiNAF
5A R Receive Remote Alarm Bits RRA
5B R Receive Sa4 Bits RSa4
5C R Receive Sa5 Bits RSa5
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ADDRESS R/W REGISTER NAME REGISTER
ABBREVIATION
5D R Receive Sa6 Bits RSa6
5E R Receive Sa7 Bits RSa7
5F R Receive Sa8 Bits RSa8
60 R/W Transmit Channel 1 TC1
61 R/W Transmit Channel 2 TC2
62 R/W Transmit Channel 3 TC3
63 R/W Transmit Channel 4 TC4
64 R/W Transmit Channel 5 TC5
65 R/W Transmit Channel 6 TC6
66 R/W Transmit Channel 7 TC7
67 R/W Transmit Channel 8 TC8
68 R/W Transmit Channel 9 TC9
69 R/W Transmit Channel 10 TC10
6A R/W Transmit Channel 11 TC11
6B R/W Transmit Channel 12 TC12
6C R/W Transmit Channel 13 TC13
6D R/W Transmit Channel 14 TC14
6E R/W Transmit Channel 15 TC15
6F R/W Transmit Channel 16 TC16
70 R/W Transmit Channel 17 TC17
71 R/W Transmit Channel 18 TC18
72 R/W Transmit Channel 19 TC19
73 R/W Transmit Channel 20 TC20
74 R/W Transmit Channel 21 TC21
75 R/W Transmit Channel 22 TC22
76 R/W Transmit Channel 23 TC23
77 R/W Transmit Channel 24 TC24
78 R/W Transmit Channel 25 TC25
79 R/W Transmit Channel 26 TC26
7A R/W Transmit Channel 27 TC27
7B R/W Transmit Channel 28 TC28
7C R/W Transmit Channel 29 TC29
7D R/W Transmit Channel 30 TC30
7E R/W Transmit Channel 31 TC31
7F R/W Transmit Channel 32 TC32
80 R/W Receive Channel 1 RC1
81 R/W Receive Channel 2 RC2
82 R/W Receive Channel 3 RC3
83 R/W Receive Channel 4 RC4
84 R/W Receive Channel 5 RC5
85 R/W Receive Channel 6 RC6
86 R/W Receive Channel 7 RC7
87 R/W Receive Channel 8 RC8
88 R/W Receive Channel 9 RC9
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ADDRESS R/W REGISTER NAME REGISTER
ABBREVIATION
89 R/W Receive Channel 10 RC10
8A R/W Receive Channel 11 RC11
8B R/W Receive Channel 12 RC12
8C R/W Receive Channel 13 RC13
8D R/W Receive Channel 14 RC14
8E R/W Receive Channel 15 RC15
8F R/W Receive Channel 16 RC16
90 R/W Receive Channel 17 RC17
91 R/W Receive Channel 18 RC18
92 R/W Receive Channel 19 RC19
93 R/W Receive Channel 20 RC20
94 R/W Receive Channel 21 RC21
95 R/W Receive Channel 22 RC22
96 R/W Receive Channel 23 RC23
97 R/W Receive Channel 24 RC24
98 R/W Receive Channel 25 RC25
99 R/W Receive Channel 26 RC26
9A R/W Receive Channel 27 RC27
9B R/W Receive Channel 28 RC28
9C R/W Receive Channel 29 RC29
9D R/W Receive Channel 30 RC30
9E R/W Receive Channel 31 RC31
9F R/W Receive Channel 32 RC32
A0 R/W Transmit Channel Control 1 TCC1
A1 R/W Transmit Channel Control 2 TCC2
A2 R/W Transmit Channel Control 3 TCC3
A3 R/W Transmit Channel Control 4 TCC4
A4 R/W Receive Channel Control 1 RCC1
A5 R/W Receive Channel Control 2 RCC2
A6 R/W Receive Channel Control 3 RCC3
A7 R/W Receive Channel Control 4 RCC4
A8 R/W Common Control 4 CCR4
A9 R Transmit DS0 Monitor TDS0M
AA R/W Common Control 5 CCR5
AB R Receive DS0 Monitor RDS0M
AC R/W Test 3 TEST3 (set to 00H)
AD Not used (set to 00H)
AE Not used (set to 00H)
AF Not used (set to 00H)
B0 R/W HDLC Control Register HCR
B1 R/W HDLC Status Register HSR
B2 R/W HDLC Interrupt Mask Register HIMR
B3 R/W Receive HDLC Information Register RHIR
B4 R/W Receive HDLC FIFO Register RHFR
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ADDRESS R/W REGISTER NAME REGISTER
ABBREVIATION
B5 R/W Interleave Bus Operation Register IBO
B6 R/W Transmit HDLC Information Register THIR
B7 R/W Transmit HDLC FIFO Register THFR
B8 R/W Receive HDLC DS0 Control Register 1 RDC1
B9 R/W Receive HDLC DS0 Control Register 2 RDC2
BA R/W Transmit HDLC DS0 Control Register 1 TDC1
BB R/W Transmit HDLC DS0 Control Register 2 TDC2
BC Not used (set to 00H)
BD Not used (set to 00H)
BE Not used (set to 00H)
BF Not used (set to 00H)
NOTES:
1. Test Registers 1, 2, and 3 are used only by the factory; these registers must be cleared (set to all
zeros) on power– up initialization to insure proper operation.
2. Register banks CxH, DxH, ExH, and FxH are not accessible.
4. PARALLEL PORT
The DS21FT40 is controlled via either a non–multiplexed (MUX = 0) or a multiplexed (MUX = 1) bus by
an external microcontroller or microprocessor. The DS21FT40 can operate with either Intel or Motorola
bus timing configurations. If the BTS pin is tied low, Intel timing will be selected; if tied high, Motorola
timing will be selected. All Motorola bus signals are listed in parenthesis (). See the timing diagrams in
the A.C. Electrical Characteristics in Section 17 for more details.
5. CONTROL, ID AND TEST REGISTERS
The operation of each framer within the DS21FT40 is configured via a set of ten control registers.
Typically, the control registers are only accessed when the system is first powered up. Once a channel in
the DS21FT40 has been initialized, the control registers will only need to be accessed when there is a
change in the system configuration. There are two Receive Control Register (RCR1 and RCR2), two
Transmit Control Registers (TCR1 and TCR2), and six Common Control Registers (CCR1 to CCR6).
Each of the ten registers are described in this section.
There is a device Identification Register (IDR) at address 0Fh. The MSB of this read–only register is
fixed to a one indicating that the DS21Q44 die is present. The lower 4 bits of the IDR are used to display
the die revision of the chip.
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25 of 87
Power–Up Sequence
The DS21FT40 does not automatically clear its register space on power–up. After the supplies are stable,
each of the four framer’s register space should be configured for operation by writing to all of the internal
registers. This includes setting the Test and all unused registers to 00Hex.
This can be accomplished using a two-pass approach on each quad framer within the DS21FT40.
1. Clear each quad framer’s register space by writing 00H to addresses 00H through 0BFH.
2. Program required registers to achieve desired operating mode.
Finally, after the TSYSCLK and RSYSCLK inputs are stable, the ESR bit should be toggled from a zero
to a one (this step can be skipped if the elastic stores are disabled).
IDR: DEVICE IDENTIFICATION REGISTER (Address=0F Hex)
(MSB) (LSB)
T1E1 0 0 0 ID3 ID2 ID1 ID0
SYMBOLS POSITION NAME AND DESCRIPTION
T1E1 IDR.7 T1 or E1 Chip Determination Bit.
0=T1 chip
1=E1 chip
ID3 IDR.3 Chip Revision Bit 3. MSB of a decimal code that represents
the chip revision.
ID2 IDR.1 Chip Revision Bit 2.
ID1 IDR.2 Chip Revision Bit 1.
ID0 IDR.0 Chip Revision Bit 0. LSB of a decimal code that represents
the chip revision.
RCR1: RECEIVE CONTROL REGISTER 1 (Address=10 Hex)
(MSB) (LSB)
RSMF RSM RSIO FRC SYNCE RESYNC
SYMBOLS POSITION NAME AND DESCRIPTION
RSMF RCR1.7 RSYNC Multiframe Function. Only used if the RSYNC pin
is programmed in the multiframe mode (RCR1.6=1).
0 = RSYNC outputs CAS multiframe boundaries
1 = RSYNC outputs CRC4 multiframe boundaries
RSM RCR1.6 RSYNC Mode Select.
0 = frame mode (see the timing in Section 18)
1 = multiframe mode (see the timing in Section 18)
RSIO RCR1.5 RSYNC I/O Select. (note: this bit must be set to zero when
RCR2.1=0).
0 = RSYNC is an output (depends on RCR1.6)
1 = RSYNC is an input (only valid if elastic store enabled)
RCR1.4 Not Assigned. Should be set to zero when written.
RCR1.3 Not Assigned. Should be set to zero when written.
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SYMBOLS POSITION NAME AND DESCRIPTION
FRC RCR1.2 Frame Resync Criteria.
0 = resync if FAS received in error 3 consecutive times
1 = resync if FAS or bit 2 of non–FAS is received in error 3
consecutive times
SYNCE RCR1.1 Sync Enable.
0 = auto resync enabled
1 = auto resync disabled
RESYNC RCR1.0 Resync. When toggled from low to high, a resync is initiated.
Must be cleared and set again for a subsequent resync.
SYNC/RESYNC CRITERI A Table 5–1
FRAME OR
MULTIFRAME
LEVEL
SYNC CRITERIA RESYNC CRITERIA ITU SPEC.
FAS FAS present in frame N and
N + 2, and FAS not present
in frame N + 1
Three consecutive incorrect
FAS received
Alternate (RCR1.2=1) the
above criteria is met or
three consecutive incorrect
bit 2 of non–FAS received
G.706
4.1.1
4.1.2
CRC4 Two valid MF alignment
words found within 8 ms 915 or more CRC4 code
words out of 1000 received
in error
G.706
4.2 and 4.3.2
CAS Valid MF alignment word
found and previous timeslot
16 contains code other than
all zeros
Two consecutive MF
alignment words received
in error
G.732 5.2
RCR2: RECEIVE CONTROL REGISTER 2 (Address=11 Hex)
(MSB) (LSB)
Sa8S Sa7S Sa6S Sa5S Sa4S RBCS RESE
SYMBOLS POSITION NAME AND DESCRIPTION
Sa8S RCR2.7 Sa8 Bit Select. Not applicable for DS21FT40.
Sa7S RCR2.6 Sa7 Bit Select. Not applicable for DS21FT40.
Sa6S RCR2.5 Sa6 Bit Select. Not applicable for DS21FT40.
Sa5S RCR2.4 Sa5 Bit Select. Not applicable for DS21FT40.
Sa4S RCR2.3 Sa4 Bit Select. Not applicable for DS21FT40.
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SYMBOLS POSITION NAME AND DESCRIPTION
RBCS RCR2.2 Receive Side Backplane Clock Select.
0 = if RSYSCLK is 1.544 MHz
1 = if RSYSCLK is 2.048 MHz
RESE RCR2.1 Receive Side Elastic Store Enable.
0 = elastic store is bypassed
1 = elastic store is enabled
RCR2.0 Not Assigned. Should be set to zero when written.
TCR1: TRANSM IT CONTROL REGISTER 1 (Address=12 Hex)
(MSB) (LSB)
ODF TFPT T16S TUA1 TSiS TSA1 TSM TSIO
SYMBOLS POSITION NAME AND DESCRIPTION
ODF TCR1.7 Output Data Format.
0 = bipolar data at TPOS and TNEG
1 = NRZ data at TPOS; TNEG=0
TFPT TCR1.6 Transmit Timeslot 0 Pass Through.
0 = FAS bits/Sa bits/Remote Alarm sourced internally from
the TAF and TNAF registers
1 = FAS bits/Sa bits/Remote Alarm sourced from TSER
T16S TCR1.5 Transmit Timeslot 16 Data Select.
0 = sample timeslot 16 at TSER pin
1 = source timeslot 16 from TS0 to TS15 registers
TUA1 TCR1.4 Transmit Unframed All Ones.
0 = transmit data normally
1 = transmit an unframed all one’s code at TPOS and TNEG
TSiS TCR1.3 Transmit International Bit Select.
0 = sample Si bits at TSER pin
1 = source Si bits from TAF and TNAF registers (in this
mode, TCR1.6 must be set to 0)
TSA1 TCR1.2 Transmit Signaling All Ones.
0 = normal operation
1 = force timeslot 16 in every frame to all ones
TSM CR1.1 TSYNC Mode Select.
0 = frame mode (see the timing in Section 16)
1 = CAS and CRC4 multiframe mode (see the timing in
Section 16)
TSIO TCR1.0 TSYNC I/O Select.
0 = TSYNC is an input
1 = TSYNC is an output
NOTE:
See Figure 16–15 for more details about how the Transmit Control Registers affect the operation of the
DS21FT40.
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TCR2: TRANSM IT CONTROL REGISTER 2 (Address=13 Hex)
(MSB) (LSB)
Sa8S Sa7S Sa6S Sa5S Sa4S ODM AEBE PF
SYMBOLS POSITION NAME AND DESCRIPTION
Sa8S TCR2.7 Sa8 Bit Select. Not applicable for DS21FT40.
Sa7S TCR2.6 Sa7 Bit Select. Not applicable for DS21FT40.
Sa6S TCR2.5 Sa6 Bit Select. Not applicable for DS21FT40.
Sa5S TCR2.4 Sa5 Bit Select. Not applicable for DS21FT40.
Sa4S TCR2.3 Sa4 Bit Select. Not applicable for DS21FT40.
ODM TCR2.2 Output Data Mode.
0 = pulses at TPOSO and TNEGO are one full TCLKO period
wide
1 = pulses at TPOSO and TNEGO are 1/2 TCLKO period
wide
AEBE TCR2.1 Automatic E–Bit Enable.
0 = E–bits not automatically set in the transmit direction
1 = E–bits automatically set in the transmit direction
PF TCR2.0 Function of RLOS/LOTC Pin.
Not applicable for DS21FT40. Should be cleared to zero.
CCR1: COMMON CONTROL REGISTER 1 (Address=14 Hex)
(MSB) (LSB)
FLB THDB3 TG802 TCRC4 RSM RHDB3 RG802 RCRC4
SYMBOLS POSITION NAME AND DESCRIPTION
FLB CCR1.7 Framer Loopback.
0=loopback disabled
1=loopback enabled
THDB3 CCR1.6 Transmit HDB3 Enable.
0=HDB3 disabled
1=HDB3 enabled
TG802 CCR1.5 Transmit G.802 Enable. See Section 16 for details.
Not applicable for DS21FT40. Should be cleared to zero.
TCRC4 CCR1.4 Transmit CRC4 Enable.
0=CRC4 disabled
1=CRC4 enabled
RSM CCR1.3 Receive Signaling Mode Select.
0=CAS signaling mode
1=CCS signaling mode
RHDB3 CCR1.2 Receive HDB3 Enable.
0=HDB3 disabled
1=HDB3 enabled
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SYMBOLS POSITION NAME AND DESCRIPTION
RG802 CCR1.1 Receive G.802 Enable. See Section 16 for details.
Not applicable for DS21FT40. Should be cleared to zero.
RCRC4 CCR1.0 Receive CRC4 Enable.
0=CRC4 disabled
1=CRC4 enabled
FRAMER LOOPBACK
When CCR1.7 is set to a one, the framer will enter a Framer LoopBack (FLB) mode. See Figure 1–2 for
more details. This loopback is useful in testing and debugging applications. In FLB, the framer will loop
data from the transmit side back to the receive side. When FLB is enabled, the following will occur:
1. Data will be transmitted as normal at TPOS and TNEG.
2. Data input via RPOS and RNEG will be ignored.
3. The RCLK output will be replaced with the TCLK input.
CCR2: COMMON CONTROL REGISTER 2 (Address=1A Hex)
(MSB) (LSB)
ECUS VCRFS AAIS ARA RSERC LOTCMC RFF RFE
SYMBOLS POSITION NAME AND DESCRIPTION
ECUS CCR2.7 Error Counter Update Select. See Section 7 for details.
0=update error counters once a second
1=update error counters every 62.5 ms (500 frames)
VCRFS CCR2.6 VCR Function Select. See Section 7 for details.
0=count BiPolar Violations (BPVs)
1=count Code Violations (CVs)
AAIS CCR2.5 Automatic AIS Generation.
0=disabled
1=enabled
ARA CCR2.4 Automatic Remote Alarm Generation.
0=disabled
1=enabled
RSERC CCR2.3 RSER Control.
0=allow RSER to output data as received under all conditions
1=force RSER to one under loss of frame alignment conditions
LOTCMC CCR2.2 Loss of Transmit Clock Mux Control. Determines whether the
transmit side formatter should switch to the ever present RCLK
if the TCLK should fail to transition (see Figure 1–2).
0=do not switch to RCLK if TCLK stops
1=switch to RCLK if TCLK stops
RFF CCR2.1 Receive Force Freeze. Freezes receive side signaling at RSER
(if CCR3.3=1); will override Receive Freeze Enable (RFE).
See Section 9 for details.
0=do not force a freeze event
1=force a freeze event
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SYMBOLS POSITION NAME AND DESCRIPTION
RFE CCR2.0 Receive Freeze Enable. See Section 9 for details.
0=no freezing of receive signaling data will occur
1=allow freezing of receive signaling data at RSER (if
CCR3.3=1).
AUTOMATIC ALARM GENERATION
The DS21FT40 can be programmed to automatically transmit AIS or Remote Alarm. When automatic
AIS generation is enabled (CCR2.5 = 1), the framer monitors the receive side to determine if any of the
following conditions are present: loss of receive frame synchronization, AIS alarm (all one’s) reception,
or loss of receive carrier (or signal). If any one (or more) of the above conditions is present, then the
framer will transmit an AIS alarm.
When automatic RAI generation is enabled (CCR2.4 = 1), the framer monitors the receive side to
determine if any of the following conditions are present: loss of receive frame synchronization, AIS alarm
(all one’s) reception, loss of receive carrier or if CRC4 multiframe synchronization (if enabled) cannot be
found within 128 ms of FAS synchronization. If any one (or more) of the above conditions is present,
then the framer will transmit a RAI alarm. RAI generation conforms to ETS 300 011 specifications and a
constant Remote Alarm will be transmitted if the framer cannot find CRC4 multiframe synchronization
within 400 ms as per G.706.
It is an illegal state to have both CCR2.4 and CCR2.5 set to one at the same time.
CCR3: COMMON CONTROL REGISTER 3 (Address=1B Hex)
(MSB) (LSB)
TESE TCBFS TIRFS RSRE THSE TBCS RCLA
SYMBOLS POSITION NAME AND DESCRIPTION
TESE CCR3.7 Transmit Side Elastic Store Enable.
0=elastic store is bypassed
1=elastic store is enabled
TCBFS CCR3.6 Transmit Channel Blocking Registers (TCBR) Function Select.
0=TCBRs define the operation of the TCHBLK output pin (not
applicable for DS21FT40)
1=TCBRs define which signaling bits are to be inserted
TIRFS CCR3.5 Transmit Idle Registers (TIR) Function Select. See Section 10
for details.
0=TIRs define in which channels to insert idle code
1=TIRs define in which channels to insert data from RSER
(i.e., Per Channel Loopback function)
CCR3.4 Not Assigned. Should be set to zero when written.
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SYMBOLS POSITION NAME AND DESCRIPTION
RSRE CCR3.3 Receive Side Signaling Re–Insertion Enable. See Section 9 for
details.
0=do not re–insert signaling bits into the data stream presented
at the RSER pin
1=re–insert the signaling bits into data stream presented at the
RSER pin
THSE CCR3.2 Transmit Side Hardware Signaling Insertion Enable.
Not applicable for DS21FT40. Should be cleared to zero.
TBCS CCR3.1 Transmit Side Backplane Clock Select.
0=if TSYSCLK is 1.544 MHz
1=if TSYSCLK is 2.048 MHz
RCLA CCR3.0 Receive Carrier Loss (RCL) Alternate Criteria.
0=RCL declared upon 255 consecutive zeros (125 us)
1=RCL declared upon 2048 consecutive zeros (1 ms)
CCR4: COMMON CONTROL REGISTER 4 (Address=A8 Hex)
(MSB) (LSB)
RLB TCM4 TCM3 TCM2 TCM1 TCM0
SYMBOLS POSITION NAME AND DESCRIPTION
RLB CCR4.7 Remote Loopback.
0 = loopback disabled
1 = loopback enabled
CCR4.6 Not Assigned. Should be set to zero when written.
CCR4.5 Not Assigned. Should be set to zero when written.
TCM4 CCR4.4 Transmit Channel Monitor Bit 4. MSB of a channel decode
that deter-mines which transmit channel data will appear in the
TDS0M register. See Section 8 for details.
TCM3 CCR4.3 Transmit Channel Monitor Bit 3.
TCM2 CCR4.2 Transmit Channel Monitor Bit 2.
TCM1 CCR4.1 Transmit Channel Monitor Bit 1.
TCM0 CCR4.0 Transmit Channel Monitor Bit 0. LSB of the channel decode.
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CCR5: COMMON CONTROL REGISTER 5 (Address = AA Hex)
(MSB) (LSB)
RESALGN TESALGN RCM4 RCM3 RCM2 RCM1 RCM0
SYMBOLS POSITION NAME AND DESCRIPTION
CCR5.7 Not Assigned. Should be set to zero when written
RESALGN CCR5.6 Receive Elastic Store Align. Setting this bit from a zero to a
one may force the receive elastic store’s write/read pointers to
a minimum separation of half a frame. No action will be taken
if the pointer separation is already greater or equal to half a
frame. If pointer separation is less then half a frame, the
command will be executed and data will be disrupted. Should
be toggled after RSYSCLK has been applied and is stable.
Must be cleared and set again for a subsequent align. See
Section 12 for details.
TESALGN CCR5.5 Transmit Elastic Store Align. Setting this bit from a zero to a
one may force the transmit elastic store’s write/read pointers to
a minimum separation of half a frame. No action will be taken
if the pointer separation is already greater or equal to half a
frame. If pointer separation is less then half a frame, the
command will be executed and data will be disrupted. Should
be toggled after TSYSCLK has been applied and is stable.
Must be cleared and set again for a subsequent align. See
Section 12 for details.
RCM4 CCR5.4 Receive Channel Monitor Bit 4. MSB of a channel decode that
determines which receive channel data will appear in the
RDS0M register. See Section 8 for details.
RCM3 CCR5.3 Receive Channel Monitor Bit 3.
RCM2 CCR5.2 Receive Channel Monitor Bit 2.
RCM1 CCR5.1 Receive Channel Monitor Bit 1.
RCM0 CCR5.0 Receive Channel Monitor Bit 0. LSB of the channel decode.
CCR6: COMMON CONTROL REGISTER 6 (Address=1D Hex)
(MSB) (LSB)
TCLKSRC RESR TESR
SYMBOLS POSITION NAME AND DESCRIPTION
CCR6.7 Not Assigned. Should be set to zero when written
CCR6.6 Not Assigned. Should be set to zero when written
CCR6.5 Not Assigned. Should be set to zero when written
CCR6.4 Not Assigned. Should be set to zero when written
CCR6.3 Not Assigned. Should be set to zero when written
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SYMBOLS POSITION NAME AND DESCRIPTION
TCLKSRC CCR6.2 Transmit Clock Source Select. This function allows the user to
internally select RCLK as the clock source for the transmit side
formatter.
0 = Transmit side formatter clocked with signal applied at
TCLK pin. LOTC Mux function is operational (TCR1.7)
1 = Transmit side formatter clocked with RCLK.
RESR CCR6.1 Receive Elastic Store Reset. Setting this bit from a zero to a
one will force the receive elastic store to a depth of one frame.
Receive data is lost during the reset. Should be toggled after
RSYSCLK has been applied and is stable. Do not leave this
bit set high.
TESR CCR6.0 Transmit Elastic Store Reset. Setting this bit from a zero to a
one will force the transmit elastic store to a depth of one frame.
Transmit data is lost during the reset. Should be toggled after
TSYSCLK has been applied and is stable. Do not leave this
bit set high.
6. STATUS AND INFORMATION REGISTERS
There is a set of seven registers per framer that contain information on the current real time status of a
framer in the DS21FT40, Status Register 1 (SR1), Status Register 2 (SR2), Receive Information Register
(RIR), Synchronizer status Register (SSR) and a set of three registers for the onboard HDLC controller.
The specific details on the four registers pertaining to the HDLC controller are covered in Section 14 but
they operate the same as the other status registers in the DS21FT40 and this operation is described below.
When a particular event has occurred (or is occurring), the appropriate bit in one of these four registers
will be set to a one. All of the bits in SR1, SR2, and RIR1 registers operate in a latched fashion. The
Synchronizer status Register contents are not latched. This m eans that if an event or an alarm occurs and
a bit is set to a one in any of the registers, it will remain set until the user reads that bit. The bit will be
cleared when it is read and it will not be set again until the event has occurred again (or in the case of the
RSA1, RSA0, RDMA, RUA1, RRA, RCL, and RLOS alarms, the bit will remain set if the alarm is still
present).
The user will always precede a read of any of the SR1, SR2 and RIR registers with a write. The byte
written to the register will inform the framer which bits the user wishes to read and have cleared. The
user will write a byte to one of these registers, with a one in the bit positions he or she wishes to read and
a zero in the bit positions he or she does not wish to obtain the latest information on. When a one is
written to a bit location, the read register will be updated with the latest information. When a zero is
written to a bit position, the read register will not be updated and the previous value will be held. A write
to the status and information registers will be immediately followed by a read of the same register. The
read result should be logically AND’ed with the mask byte that was just written and this value should be
written back into the same register to insure that bit does indeed clear. This second write step is necessary
because the alarms and events in the status registers occur asynchronously in respect to their access via
the parallel port. This write–read– write scheme allows an external microcontroller or microprocessor to
individually poll certain bits without disturbing the other bits in the register. This operation is key in
controlling the DS21FT40 with higher–order software languages.
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The SSR register operates differently than the other three. It is a read only register and it reports the status
of the synchronizer in real time. This register is not latched and it is not necessary to precede a read of
this register with a write.
The SR1, SR2, and HSR registers have the unique ability to initiate a hardware interrupt via the INT*
output pin. Each of the alarms and events in the SR1, SR2, and HSR can be either masked or unmasked
from the interrupt pin via the Interrupt Mask Register 1 (IMR1), Interrupt Mask Register 2 (IMR2), and
HDLC Interrupt Mask Register (HIMR) respectively. The HIMR register is covered in Section 14.
The interrupts caused by four of the alarms in SR1 (namely RUA1, RRA, RCL, and RLOS) act differently
than the interrupts caused by other alarms and events in SR1 and SR2 (namely RSA1, RDMA, RSA0,
RSLIP, RMF, RAF, TMF, SEC, TAF, LOTC, RCMF, and TSLIP). These four alarm interrupts will force
the INT* pin low whenever the alarm changes state (i.e., the alarm goes active or inactive according to the
set/clear criteria in Table 6-1). The INT* pin will be allowed to return high (if no other interrupts are
present) when the user reads the alarm bit that caused the interrupt to occur. If the alarm is still present,
the register bit will remain set.
The event caused interrupts will force the INT* pin low when the event occurs. The INT* pin will be
allowed to retu rn high (if no other interrupts are present ) when the user reads the event bi t that caused the
interrupt to occur.
ISR: INTERRUPT STATUS REGISTER
(Any address from 0C0 Hex to 0FF Hex)
(MSB) (LSB)
F3HDLC F3SR F2HDLC F2SR F1HDLC F1SR F0HDLC F0SR
SYMBOLS POSITION NAME AND DESCRIPTION
F3HDLC ISR.7 FRAMER 3 HDLC CONTROLLER INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
F3SR ISR.6 FRAMER 3 SR1 or SR2 INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
F2HDLC ISR.5 FRAMER 2 HDLC CONTROLLER INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
F2SR ISR.4 FRAMER 2 SR1 or SR2 INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
F1HDLC ISR.3 FRAMER 1 HDLC CONTROLLER INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
F1SR ISR.2 FRAMER 1 SR1 or SR2 INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
F0HDLC ISR.1 FRAMER 0 HDLC CONTROLLER INTERRUPT REQUEST.
0 = No interrupt request pending.
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SYMBOLS POSITION NAME AND DESCRIPTION
1 = Interrupt request pending.
F0SR ISR.0 FRAMER 0 SR1 or SR2 INTERRUPT REQUEST.
0 = No interrupt request pending.
1 = Interrupt request pending.
RIR: RECEIVE INFORMATION REGISTER (Address=08 Hex)
(MSB) (LSB)
TESF TESE RESF RESE CRCRC FASRC CASRC
SYMBOLS POSITION NAME AND DESCRIPTION
TESF RIR.7 Transmit Side Elastic Store Full. Set when the transmit side
elastic store buffer fills and a frame is deleted.
TESE RIR.6 Transmit Side Elastic Store Empty. Set when the transmit side
elastic store buffer empties and a frame is repeated.
RIR.5 Not Assigned. Could be any value.
RESF RIR.4 Receive Side Elastic Store Full. Set when the receive side
elastic store buffer fills and a frame is deleted.
RESE RIR.3 Receive Side Elastic Store Empty. Set when the receive side
elastic store buffer empties and a frame is repeated.
CRCRC RIR.2 CRC Resync Criteria Met. Set when 915/1000 code words are
received in error.
FASRC RIR.1 FAS Resync Criteria Met. Set when 3 consecutive FAS words
are received in error.
CASRC RIR.0 CAS Resync Criteria Met. Set when 2 consecutive CAS MF
alignment words are received in error.
SSR: SYNCHRONIZER STATUS REGI STER (Address=1E Hex)
(MSB) (LSB)
CSC5 CSC4 CSC3 CSC2 CSC0 FASSA CASSA CRC4SA
SYMBOLS POSITION NAME AND DESCRIPTION
CSC5 SSR.7 CRC4 Sync Counter Bit 5. MSB of the 6–bit counter.
CSC4 SSR.6 CRC4 Sync Counter Bit 4.
CSC3 SSR.5 CRC4 Sync Counter Bit 3.
CSC2 SSR.4 CRC4 Sync Counter Bit 2.
CSC0 SSR.3 CRC4 Sync Counter Bit 0. LSB of the 6–bit counter. The next
to LSB is not accessible.
FASSA SSR.2 FAS Sync Active. Set while the synchronizer is searching for
alignment at the FAS level.
CASSA SSR.1 CAS MF Sync Active. Set while the synchronizer is searching
for the CAS MF alignment word.
CRC4SA SSR.0 CRC4 MF Sync Active. Set while the synchronizer is
searching for the CRC4 MF alignment word.
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CRC4 SYNC COUNTER
The CRC4 Sync Counter increments each time the 8 ms CRC4 multiframe search times out. The counter
is cleared when the framer has successfully obtained synchronization at the CRC4 level. The counter can
also be cleared by disabling the CRC4 mode (CCR1.0=0). This counter is useful for determining the
amount of time the framer has been searching for synchronization at the CRC4 level. ITU G.706 suggests
that if synchronization at the CRC4 level cannot be obtained within 400 ms, then the search should be
abandoned and proper action taken. The CRC4 Sync Counter will rollover.
SR1: STATUS REGISTER 1 (Address=06 Hex)
(MSB) (LSB)
RSA1 RDMA RSA0 RSLIP RUA1 RRA RCL RLOS
SYMBOLS POSITION NAME AND DESCRIPTION
RSA1 SR1.7 Receive Signaling All Ones / Signaling Change. Set when
over a full MF, the content of timeslot 16 contains less than
three zeros. This alarm is not disabled in the CCS signaling
mode. A change in the contents of RS1 through RS16 from
one multiframe to the next will cause RSA1 and RSA0 to be
set.
RDMA SR1.6 Receive Distant MF Alarm. Set when bit–6 of timeslot 16 in
frame 0 has been set for two consecutive multiframes. This
alarm is not disabled in the CCS signaling mode.
RSA0 SR1.5 Receive Signaling All Zeros / Signaling Change. Set when
over a full MF, timeslot 16 contains all zeros. A change in the
contents of RS1 through RS16 from one multiframe to the next
will cause RSA1 and RSA0 to be set.
RSLIP SR1.4 Receive Side Elastic Store Slip. Set when the elastic store has
either repeated or deleted a frame of data.
RUA1 SR1.3 Receive Unframed All Ones. Set when an unframed all ones
code is received at RPOS and RNEG.
RRA SR1.2 Receive Remote Alarm. Set when a remote alarm is received
at RPOS and RNEG.
RCL SR1.1 Receive Carrier Loss. Set when 255 (or 2048 if CCR3.0=1)
consecutive zeros have been detected at RPOS and RNEG.
RLOS SR1.0 Receive Loss of Sync. Set when the device is not
synchronized to the receive E1 stream.
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ALARM CRITERIA Table 6-1
ALARM SET CRITERIA CLEAR CRITERIA ITU
SPEC.
RSA1 (receive
signaling all ones) over 16 consecutive frames
(one full MF) timeslot 16
contains less than three zeros
over 16 consecutive frames
(one full MF) timeslot 16
contains three or more zeros
G.732
4.2
RSA0 (receive
signaling all zeros) over 16 consecutive frames
(one full MF) timeslot 16
contains all zeros
over 16 consecutive frames
(one full MF) timeslot 16
contains at least a single one
G.732
5.2
RDMA (receive
distant multiframe
alarm)
bit 6 in timeslot 16 of frame 0
set to one for two consecutive
MF
bit 6 in timeslot 16 of frame 0
set to zero for two
consecutive MF
O.162
2.1.5
RUA1 (receive
unframed all ones) less than three zeros in two
frames (512 bits) more than two zeros in two
frames (512 bits) O.162
1.6.1.2
RRA (receive remote
alarm) bit 3 of non–align frame set
to one for three consecutive
occasions
bit 3 of non–align frame set
to zero for three consecutive
occasions
O.162
2.1.4
RCL (receive carrier
loss) 255 (or 2048) consecutive
zeros received in 255 bit times, at least 32
ones are received G.775 / G.962
SR2: STATUS REGISTER 2 (Address=07 Hex)
(MSB) (LSB)
RMF RAF TMF SEC TAF LOTC RCMF TSLIP
SYMBOLS POSITION NAME AND DESCRIPTION
RMF SR2.7 Receive CAS Multiframe. Set every 2 ms (regardless if CAS
signaling is enabled or not) on receive multiframe boundaries.
Used to alert the host that signaling data is available.
RAF SR2.6 Receive Align Frame. Set every 250 s at the beginning of
align frames. Used to alert the host that Si and Sa bits are
available in the RAF and RNAF registers.
TMF SR2.5 Transmit Multiframe. Set every 2 ms (regardless if CRC4 is
enabled) on transmit multiframe boundaries. Used to alert the
host that signaling data needs to be updated.
SEC SR2.4 One Second Timer. Set on increments of one second based on
RCLK. If CCR2.7=1, then this bit will be set every 62.5 ms
instead of once a second.
TAF SR2.3 Transmit Align Frame. Set every 250 s at the beginning of
align frames. Used to alert the host that the TAF and TNAF
registers need to be updated.
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SYMBOLS POSITION NAME AND DESCRIPTION
LOTC SR2.2 Loss of Transmit Clock. Set when the TCLK pin has not
transitioned for one channel time (or 3.9 s).
RCMF SR2.1 Receive CRC4 Multiframe. Set on CRC4 multiframe
boundaries; will continue to be set every 2 ms on an arbitrary
boundary if CRC4 is disabled.
TSLIP SR2.0 Transmit Elastic Store Slip. Set when the elastic store has
either repeated or deleted a frame of data.
IM R1: INTERRUPT MASK REGISTER 1 (Address=16 Hex)
(MSB) (LSB)
RSA1 RDMA RSA0 RSLIP RUA1 RRA RCL RLOS
SYMBOLS POSITION NAME AND DESCRIPTION
RSA1 IMR1.7 Receive Signaling All Ones / Signaling Change.
0=interrupt masked
1=interrupt enabled
RDMA IMR1.6 Receive Distant MF Alarm.
0=interrupt masked
1=interrupt enabled
RSA0 IMR1.5 Receive Signaling All Zeros / Signaling Change.
0=interrupt masked
1=interrupt enabled
RSLIP IMR1.4 Receive Elastic Store Slip Occurrence.
0=interrupt masked
1=interrupt enabled
RUA1 IMR1.3 Receive Unframed All Ones.
0=interrupt masked
1=interrupt enabled
RRA IMR1.2 Receive Remote Alarm.
0=interrupt masked
1=interrupt enabled
RCL IMR1.1 Receive Carrier Loss.
0=interrupt masked
1=interrupt enabled
RLOS IMR1.0 Receive Loss of Sync.
0=interrupt masked
1=interrupt enabled
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IM R2: INTERRUPT MASK REGISTER 2 (Address=17 Hex)
(MSB) (LSB)
RMF RAF TMF SEC TAF LOTC RCMF TSLIP
SYMBOLS POSITION NAME AND DESCRIPTION
RMF IMR2.7 Receive CAS Multiframe.
0=interrupt masked
1=interrupt enabled
RAF IMR2.6 Receive Align Frame.
0=interrupt masked
1=interrupt enabled
TMF IMR2.5 Transmit Multiframe.
0=interrupt masked
1=interrupt enabled
SEC IMR2.4 One Second Timer.
0=interrupt masked
1=interrupt enabled
TAF IMR2.3 Transmit Align Frame.
0=interrupt masked
1=interrupt enabled
LOTC IMR2.2 Loss Of Transmit Clock.
0=interrupt masked
1=interrupt enabled
RCMF IMR2.1 Receive CRC4 Multiframe.
0=interrupt masked
1=interrupt enabled
TSLIP IMR2.0 Transmit Side Elastic Store Slip Occurrence.
0=interrupt masked
1=interrupt enabled
7. ERROR COUNT REGISTERS
There are a set of four counters in each framer that record bipolar or code violations, errors in the CRC4
SMF code words, E bits as reported by the far end, and word errors in the FAS. Each of these four
counters are automatically updated on either one second boundaries (CCR2.7=0) or every 62.5 ms
(CCR2.7=1) as determined by the timer in Status Register 2 (SR2.4). Hence, these registers contain
performance data from either the previous second or the previous 62.5 ms. The user can use the interrupt
from the one second timer to determine when to read these registers. The user has a full second (or 62.5
ms) to read the counters before the data is lost. All four counters will saturate at their respective
maximum counts and they will not rollover.
BPV or Code Violation Counter
Violation Count Register 1 (VCR1) is the most significant word and VCR2 is the least significant word of
a 16–bit counter that records either BiPolar Violations (BPVs) or Code Violations (CVs). If CCR2.6=0,
then the VCR counts bipolar violations. Bipolar violations are defined as consecutive marks of the same
polarity. In this mode, if the HDB3 mode is set for the receive side via CCR1.2, then HDB3 code words
are not counted as BPVs. If CCR2.6=1, then the VCR counts code violations as defined in ITU O.161.
Code violations are defined as consecutive bipolar violations of the same polarity. In most applications,
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the framer should be programmed to count BPVs when receiving AMI code and to count CVs when
receiving HDB3 code. This counter increments at all times and is not disabled by loss of sync conditions.
The counter saturates at 65,535 and will not rollover. The bit error rate on a E1 line would have to be
greater than 10** –2 before the VCR would saturate.
VCR1: UPPER BIPOLAR VIOLATION COUNT REGISTER 1 (Address=00 Hex)
VCR2: LOWER BIPOLAR VIOLATION COUNT REGISTER 2 (Address=01 Hex)
(MSB) (LSB)
V15 V14 V13 V12 V11 V10 V9 V8 VCR1
V7 V6 V5 V4 V3 V2 V1 V0 VCR2
SYMBOLS POSITION NAME AND DESCRIPTION
V15 VCR1.7 MSB of the 16–bit code violation count
V0 VCR2.0 LSB of the 10–bit code violation count
CRC4 Error Counter CRC4 Count Register 1 (CRCCR1) is the most significant word and CRCCR2 is the
least significant word of a 10–bit counter that records word errors in the Cyclic Redundancy Check 4
(CRC4). Since the maximum CRC4 count in a one second period is 1000, this counter cannot saturate.
The counter is disabled during loss of sync at either the FAS or CRC4 level; it will continue to count if
loss of multiframe sync occurs at the CAS level.
CRCCR1: CRC4 COUNT REGISTER 1 (Address=02 Hex)
CRCCR2: CRC4 COUNT REGISTER 2 (Address=03 Hex)
(MSB) (LSB)
(note 1) (note 1) (note 1) (note 1) (note 1) (note 1) CRC9 CRC8 CRCCR1
CRC7 CRC6 CRC5 CRC4 CRC3 CRC2 CRC1 CRC0 CRCCR2
SYMBOLS POSITION NAME AND DESCRIPTION
CRC9 CRCCR1.1 MSB of the 10–Bit CRC4 error count
CRC0 CRCCR2.0 LSB of the 10–Bit CRC4 error count
NOTE:
1. The upper 6 bits of CRCCR1 at address 02 are the most significant bits of the 12–bit FAS error
counter.
E–Bit Counter
E–bit Count Register 1 (EBCR1) is the most significant word and EBCR2 is the least significant word of
a 10–bit counter that records Far End Block Errors (FEBE) as reported in the first bit of frames 13 and 15
on E1 lines running with CRC4 multiframe. These count registers will increment once each time the
received E–bit is set to zero. Since the maximum E–bit count in a one second period is 1000, this counter
cannot saturate. The counter is disabled during loss of sync at either the FAS or CRC4 level; it will
continue to count if loss of multiframe sync occurs at the CAS level.
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EBCR1: E–BIT COUNT REGISTER 1 (Address=04 Hex)
EBCR2: E–BIT COUNT REGISTER 2 (Address=05 Hex)
(MSB) (LSB)
(note 1) (note 1) (note 1) (note 1) (note 1) (note 1) EB9 EB8 EBCR1
EB7 EB6 EB5 EB4 EB3 EB2 EB1 EB0 EBCR2
SYMBOLS POSITION NAME AND DESCRIPTION
EB9 EBCR1.1 MSB of the 10–Bit E–Bit Error Count
EB0 EBCR2.0 LSB of the 10–Bit E–Bit Error Count
NOTE:
The upper 6 bits of EBCR1 at address 04 are the least significant bits of the 12–bit FAS error counter.
FAS Error Counter
FAS Count Register 1 (FASCR1) is the most significant word and FASCR2 is the least significant word
of a 12–bit counter that records word errors in the Frame Alignment Signal in timeslot 0. This counter is
disabled when RLOS is high. FAS errors will not be counted when the framer is searching for FAS
alignment and/or synchronization at either the CAS or CRC4 multiframe level. Since the maximum FAS
word error count in a one second period is 4000, this counter cannot saturate.
FASCR1: FAS ERROR COUNT REGISTER 1 (Address=02 Hex)
FASCR2: FAS ERROR COUNT REGISTER 2 (Address=04 Hex)
(MSB) (LSB)
FAS11 FAS10 FAS9 FAS8 FAS7 FAS6 (note 2) (note 2) FASCR1
FAS5 FAS4 FAS3 FAS2 FAS1 FAS0 (note 1) (note 1) FASCR2
SYMBOLS POSITION NAME AND DESCRIPTION
FAS11 FASCR1.7 MSB of the 12–Bit FAS Error Count
FAS0 FASCR2.2 LSB of the 12–Bit FAS Error Count
NOTES:
1. The lower 2 bits of FASCR1 at address 02 are the most significant bits of the 10–bit CRC4 error
counter.
2. The lower 2 bits of FASCR2 at address 04 are the most significant bits of the 10–bit E–Bit counter.
8. DS0 MONITORING FUNCTION
Each framer in the DS21FT40 has the ability to monitor one DS0 64Kbps channel in the transmit
direction and one DS0 channel in the receive direction at the same time. In the transmit direction the user
will determine which channel is to be monitored by properly setting the TCM0 to TCM4 bits in the CCR4
register. In the receive direction, the RCM0 to RCM4 bits in the CCR5 register need to be properly set.
The DS0 channel pointed to by the TCM0 to TCM4 bits will appear in the Transmit DS0 Monitor
(TDS0M) register and the DS0 channel pointed to by the RCM0 to RCM4 bits will appear in the Receive
DS0 (RDS0M) register. The TCM4 to TCM0 and RCM4 to RCM0 bits should be programmed with the
decimal decode of the appropriate E1 channel. For example, if DS0 channel 6 (timeslot 5) in the transmit
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direction and DS0 channel 15 (timeslot 14) in the receive direction needed to be monitored, then the
following values would be programmed into CCR4 and CCR5:
TCM4 = 0 RCM4 = 0
TCM3 = 0 RCM3 = 1
TCM2 = 1 RCM2 = 1
TCM1 = 0 RCM1 = 1
TCM0 = 1 RCM0 = 0
CCR4: COMMON CONTROL REGISTER 4 (Address=A8 Hex)
[Repeated here from section 5 for convenience]
(MSB) (LSB)
RLB TCM4 TCM3 TCM2 TCM1 TCM0
SYMBOLS POSITION NAME AND DESCRIPTION
RLB CCR4.7 Remote Loopback.
0 = loopback disabled
1 = loopback enabled
CCR4.6 Not Assigned. Should be set to zero when written.
CCR4.5 Not Assigned. Should be set to zero when written.
TCM4 CCR4.4 Transmit Channel Monitor Bit 4. MSB of a channel decode
that deter-mines which transmit channel data will appear in the
TDS0M register. See Section 8 or details.
TCM3 CCR4.3 Transmit Channel Monitor Bit 3.
TCM2 CCR4.2 Transmit Channel Monitor Bit 2.
TCM1 CCR4.1 Transmit Channel Monitor Bit 1.
TCM0 CCR4.0 Transmit Channel Monitor Bit 0. LSB of the channel decode.
TDS0M: TRANSMIT DS0 MONITOR REGISTER (Address=A9 Hex)
(MSB) (LSB)
B1 B2 B3 B4 B5 B6 B7 B8
SYMBOLS POSITION NAME AND DESCRIPTION
B1 TDS0M.7 Transmit DS0 Channel Bit 1. MSB of the DS0 channel (first
bit to be transmitted).
B2 TDS0M.6 Transmit DS0 Channel Bit 2.
B3 TDS0M.5 Transmit DS0 Channel Bit 3.
B4 TDS0M.4 Transmit DS0 Channel Bit 4.
B5 TDS0M.3 Transmit DS0 Channel Bit 5.
B6 TDS0M.2 Transmit DS0 Channel Bit 6.
B7 TDS0M.1 Transmit DS0 Channel Bit 7.
B8 TDS0M.0 Transmit DS0 Channel Bit 8. LSB of the DS0 channel (last bit
to be transmitted).
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CCR5: COMMON CONTROL REGISTER 5 (Address=AA Hex)
[Repeated here from section 5 for convenience]
(MSB) (LSB)
RESALGN TESALGN RCM4 RCM3 RCM2 RCM1 RCM0
SYMBOLS POSITION NAME AND DESCRIPTION
CCR5.7 Not Assigned. Should be set to zero when written
RESALGN CCR5.6 Receive Elastic Store Align. Setting this bit from a zero to a
one may force the receive elastic store’s write/read pointers to
a minimum separation of half a frame. No action will be taken
if the pointer separation is already greater or equal to half a
frame. If pointer separation is less then half a frame, the
command will be executed and data will be disrupted. Should
be toggled after RSYSCLK has been applied and is stable.
Must be cleared and set again for a subsequent align. See
Section 12 for details.
TESALGN CCR5.5 Transmit Elastic Store Align. Setting this bit from a zero to a
one may force the transmit elastic store’s write/read pointers to
a minimum separation of half a frame. No action will be taken
if the pointer separation is already greater or equal to half a
frame. If pointer separation is less then half a frame, the
command will be executed and data will be disrupted. Should
be toggled after TSYSCLK has been applied and is stable.
Must be cleared and set again for a subsequent align. See
Section 12 for details.
RCM4 CCR5.4 Receive Channel Monitor Bit 4. MSB of a channel decode that
determines which receive channel data will appear in the
RDS0M register. See Section 8 for details.
RCM3 CCR5.3 Receive Channel Monitor Bit 3.
RCM2 CCR5.2 Receive Channel Monitor Bit 2.
RCM1 CCR5.1 Receive Channel Monitor Bit 1.
RCM0 CCR5.0 Receive Channel Monitor Bit 0. LSB of the channel decode.
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RDS0M: RECEIVE DS0 M O NITOR REGISTER (Address = AB Hex)
(MSB) (LSB)
B1 B2 B3 B4 B5 B6 B7 B8
SYMBOLS POSITION NAME AND DESCRIPTION
B1 RDS0M.7 Receive DS0 Channel Bit 1. MSB of the DS0 channel (first bit
to be received).
B2 RDS0M.6 Receive DS0 Channel Bit 2.
B3 RDS0M.5 Receive DS0 Channel Bit 3.
B4 RDS0M.4 Receive DS0 Channel Bit 4.
B5 RDS0M.3 Receive DS0 Channel Bit 5.
B6 RDS0M.2 Receive DS0 Channel Bit 6.
B7 RDS0M.1 Receive DS0 Channel Bit 7.
B8 RDS0M.0 Receive DS0 Channel Bit 8. LSB of the DS0 channel (last bit
to be received).
9. SIGNALING OPERATION
Each framer in the DS21FT40 contains provisions for both processor based (i.e., software based)
signaling bit access and for hardware based access. Both the processor based access and the hardware
based access can be used simultaneously if necessary. The processor based signaling is covered in
Section 9.1 and the hardware based signaling is covered in Section 9.2.
9.1 PROCESSOR BASED SIGNALING
The Channel Associated Signaling (CAS) bits embedded in the E1 stream can be extracted from the
receive stream and inserted into the transmit stream by the framer. Each of the 30 voice channels has four
signaling bits (A/B/C/D) associated with it. The numbers in parenthesis () are the voice channel
associated with a part icular signaling bit. The voice channel numbers have been assigned as described i n
the ITU documents. Please note that this is different than the channel numbering scheme (1 to 32) that is
used in the rest of the data sheet. For example, voice channel 1 is associated with timeslot 1 (Channel 2)
and voice Channel 30 is associated with timeslot 31 (Channel 32). There is a set of 16 registers for the
receive side (RS1 to RS16) and 16 registers on the transmit side (TS1 to TS16). The signaling registers
are detailed below.
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RS1 TO RS16: RECEIVE SIGNALING REGISTERS (Address=30 to 3F Hex)
(MSB) (LSB)
0 0 0 0 X Y X X RS1 (30)
A(1) B(1) C(1) D(1) A(16) B(16) C(16) D(16) RS2 (31)
A(2) B(2) C(2) D(2) A(17) B(17) C(17) D(17) RS3 (32)
A(3) B(3) C(3) D(3) A(18) B(18) C(18) D(18) RS3 (33)
A(4) B(4) C(4) D(4) A(19) B(19) C(19) D(19) RS5 (34)
A(5) B(5) C(5) D(5) A(20) B(20) C(20) D(20) RS6 (35)
A(6) B(6) C(6) D(6) A(21) B(21) C(21) D(21) RS7 (36)
A(7) B(7) B(7) B(7) B(22) B(22) B(22) B(22) RS8 (37)
A(8) B(8) C(8) D(8) A(23) B(23) C(23) D(23) RS9 (38)
A(9) B(9) C(9) D(9) A(24) B(24) C(24) D(24) RS10 (39)
A(10) B(10) C(10) D(10) A(25) B(25) C(25) D(25) RS11 (3A)
A(11) B(11) C(11) D(11) A(26) B(26) C(26) D(26) RS12 (3B)
A(12) B(12) C(12) D(12) A(27) B(27) C(27) D(27) RS13 (3C)
A(13) B(13) C(13) D(13) A(28) B(28) C(28) D(28) RS14 (3D)
A(14) B(14) C(14) D(14) A(29) B(29) C(29) D(29) RS15 (3E)
A(15) B(15) C(15) D(15) A(30) B(30) C(30) D(30) RS16 (3F)
SYMBOLS POSITION NAME AND DESCRIPTION
X RS1.0/1/3 Spare Bits.
Y RS1.2 Remote Alarm Bit (integrated and reported in SR1.6).
A(1) RS2.7 Signaling Bit A for Channel 1
D(30) RS16.0 Signaling Bit D for Channel 30.
Each Receive Signaling Register (RS1 to RS16) reports the incoming signaling from two timeslots. The
bits in the Receive Signaling Registers are updated on multiframe boundaries so the user can utilize the
Receive Multiframe Interrupt in the Receive Status Register 2 (SR2.7) to know when to retrieve the
signaling bits. The user has a full 2 ms to retrieve the signaling bits before the data is lost. The RS
registers are updated under all conditions. Their validity should be qualified by checking for
synchronization at the CAS level. In CCS signaling mode, RS1 to RS16 can also be used to extract
signaling information. Via the SR2.7 bit, the user will be informed when the signaling registers have
been loaded with data. The user has 2 ms to retrieve the data before it is lost. The signaling data reported
in RS1 to RS16 is also available at the RSER pin.
Three status bits in Status Register 1 (SR1) monitor the contents of registers RS1 through RS16. Status
monitored includes all zeros detection, all ones detection and a change in register contents. The Receive
Signaling All Zeros status bit (SR1.5) is set when over a full multi-frame, RS1 through RS16 contain all
zeros. The Receive Signaling All Ones status bit (SR1.7) is set when over a full multi-frame, RS1
through RS16 contain less than three zeros. A change in the contents of RS1 through RS16 from one
multiframe to the next will cause RSA1 (SR1.7) and RSA0 (SR1.5) status bits to be set at the same time.
The user can enable the INT* pin to toggle low upon detection of a change in signaling by setting either
the IMR1.7 or IMR1.5 bit. Once a signaling change has been detected, the user has at least 1.75 ms to
read the data out of the RS1 to RS16 registers before the data will be lost.
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TS1 TO TS16: TRANSMIT SIGNALING REGISTERS (Address=40 to 4F Hex)
(MSB) (LSB)
0000XYXXTS1 (40)
A(1) B(1) C(1) D(1) A(16) B(16) C(16) D(16) TS2 (41)
A(2) B(2) C(2) D(2) A(17) B(17) C(17) D(17) TS3 (42)
A(3) B(3) C(3) D(3) A(18) B(18) C(18) D(18) TS4 (43)
A(4) B(4) C(4) D(4) A(19) B(19) C(19) D(19) TS5 (44)
A(5) B(5) C(5) D(5) A(20) B(20) C(20) D(20) TS6 (45)
A(6) B(6) C(6) D(6) A(21) B(21) C(21) D(21) TS7 (46)
A(7) B(7) B(7) B(7) B(22) B(22) B(22) B(22) TS8 (47)
A(8) B(8) C(8) D(8) A(23) B(23) C(23) D(23) TS9 (48)
A(9) B(9) C(9) D(9) A(24) B(24) C(24) D(24) TS10 (49)
A(10) B(10) C(10) D(10) A(25) B(25) C(25) D(25) TS11 (4A)
A(11) B(11) C(11) D(11) A(26) B(26) C(26) D(26) TS12 (4B)
A(12) B(12) C(12) D(12) A(27) B(27) C(27) D(27) TS13 (4C)
A(13) B(13) C(13) D(13) A(28) B(28) C(28) D(28) TS14 (4D)
A(14) B(14) C(14) D(14) A(29) B(29) C(29) D(29) TS15 (4E)
A(15) B(15) C(15) D(15) A(30) B(30) C(30) D(30) TS16 (4F)
SYMBOLS POSITION NAME AND DESCRIPTION
X TS1.0/1/3 Spare Bits.
Y TS1.2 Remote Alarm Bit (integrated and reported in SR1.6).
A(1) TS2.7 Signaling Bit A for Channel 1
D(30) TS16.0 Signaling Bit D for Channel 30.
Each Transmit Signaling Register (TS1 to TS16) contains the CAS bits for two timeslots that will be
inserted into the outgoing stream if enabled to do so via TCR1.5. On multiframe boundaries, the framer
will load the values present in the Transmit Signaling Register into an outgoing signaling shift register
that is internal to the device. The user can utilize the Transmit Multiframe bit in Status Register 2
(SR2.5) to know when to update the signaling bits. The bit will be set every 2 ms and the user has 2 ms to
update the TSR’s before the old data will be retransmitted. ITU specifications recommend that the
ABCD signaling not be set to all zeros because they will emulate a CAS multiframe alignment word.
The TS1 register is special because it contains the CAS multiframe alignment word in its upper nibble.
The upper nibble must always be set to 0000 or else the terminal at the far end will lose multiframe
synchronization. If the user wishes to transmit a multiframe alarm to the far end, then the TS1.2 bit
should be set to a one. If no alarm is to be transmitted, then the TS1.2 bit should be cleared. The three
remaining bits in TS1 are the spare bits. If they are not used, they should be set to one. In CCS signaling
mode, TS1 to TS16 can also be used to insert signaling information. Via the SR2.5 bit, the user will be
informed when the signaling registers need to be loaded with data. The user has 2 ms to load the data
before the old data will be retransmitted.
Via the CCR3.6 bit, the user has the option to use the Transmit Channel Blocking Registers (TCBRs) to
determine on a channel by channel basis, which signaling bits are to be inserted via the TSRs (the
corresponding bit in the TCBRs=1) and which are to be sourced from the TSER pin. See the Transmit
Data Flow diagram in Section 16 for more details.
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TCBR1/TCBR2/TCBR3/TCBR4: DEFINITI ON WHEN CCR3.6=1
(MSB) (LSB)
CH20 CH4 CH19 CH3 CH18 CH2 CH17* CH1* TCBR1(22)
CH24 CH8 CH23 CH7 CH22 CH6 CH21 CH5 TCBR2(23)
CH28 CH12 CH27 CH11 CH26 CH10 CH25 CH9 TCBR3(24)
CH32 CH16 CH31 CH15 CH30 CH14 CH29 CH13 TCBR4(25)
*=CH1 and CH17 should be set to one to allow the internal TS1 register to create the CAS Multiframe
Alignment Word and Spare/Remote Alarm bits.
9.2 HARDWARE BASED SI GNALING
Receive Side
Hardware signaling is supported through a mode called signaling re-insertion which is invoked by setting
the RSRE control bit high (CCR3.3=1). In this mode, the user will provide a multiframe sync at the
RSYNC pin and the signaling data will be re-aligned at the RSER output according to this applied
multiframe boundary. In this mode, the elastic store must be enabled and the backplane clock must be
2.048 MHz.
The signaling data in the two multiframe buffer will be frozen in a known good state upon either a loss of
synchronization (OOF event), carrier loss, or frame slip. To allow this freeze action to occur, the RFE
control bit (CCR2.0) should be set high. The user can force a freeze by setting the RFF control bit
(CCR2.1) high. Setting the RFF bit high causes the same freezing action as if a loss of synchronization,
carrier loss, or slip has occurred.
The 2 multiframe buffer provides an approximate 1 multiframe delay in the signaling bits provided at the
RSER pin (if RSRE=1 via CCR3.3). When freezing is enabled (RFE=1), the signaling data will be held
in the last known good state until the corrupting error condition subsides. When the error condition sub-
sides, the signaling data will be held in the old state for an additional 3 ms to 5 ms before being allowed
to be updated with new signaling data.
10. PER–CHANNEL CODE GENERATION AND LOOPBACK
Each framer in the DS21FT40 can replace data on a channel–by–channel basis in both the transmit and
receive directions. The transmit direction is from the backplane to the E1 line and is covered in Section
10.1. The receive direction is from the E1 line to the backplane and is covered in Section 10.2.
10.1 TRANSMIT SIDE CODE GENERATION
In the transmit direction there are two methods by which channel data from the backplane can be
overwritten with data generated by the framer. The first method which is covered in Section 10.1.1 was a
feature contained in the original DS21Q43 while the second method which is covered in Section 10.1.2 is
a new feature of the DS21Q44.
10.1.1 Simple Idl e Code I nser tion and Per–Channel Loopback
The first method involves using the Transmit Idle Registers (TIR1/2/3/4) to determine which of the 32 E1
channels should be overwritten with the code placed in the Transmit Idle Definition Register (TIDR).
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This method allows the same 8–bit code to be placed into any of the 32 E1 channels. If this method is
used, then the CCR3.5 control bit must be set to zero.
Each of the bit position in the Transmit Idle Registers (TIR1/TIR2/TIR3/TIR4) represent a DS0 channel
in the outgoing frame. When these bits are set to a one, the corresponding channel will transmit the Idle
Code contained in the Transmit Idle Definition Register (TIDR).
The Transmit Idle Registers (TIRs) have an alternate function that allows them to define a Per–Channel
LoopBack (PCLB). If the TIRFS control bit (CCR3.5) is set to one, then the TIRs will determine which
channels (if any) from the backplane should be replaced with the data from the receive side or in other
words, off of the E1 line. If this mode is enabled, then transmit and receive clocks and frame syncs must
be synchronized.
TIR1/TIR2/TIR3: TRANSMIT IDLE REGISTERS (Address=26 to 29 Hex)
[Also used for Per–Channel Loopback]
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 TIR1 (26)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 TIR2 (27)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 TIR3 (28)
CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25 TIR4 (29)
SYMBOLS POSITIONS NAME AND DESCRIPTION
CH1 - 32 TIR1.0 - 4.7 Transmit Idle Code Insertion Control Bits.
0 = do not insert the Idle Code in the TIDR into this channel
1 = insert the Idle Code in the TIDR into this channel
NOTE:
If CCR3.5=1, then a zero in the TIRs implies that channel data is to be sourced from TSER and a one
implies that channel data is to be sourced from the output of the receive side framer (i.e., Per–Channel
Loopback; see Figure 1–2).
TIDR: TRANSMIT IDLE DEFINITION REGISTER (Address=2A Hex)
(MSB) (LSB)
TIDR7 TIDR6 TIDR5 TIDR4 TIDR3 TIDR2 TIDR1 TIDR0
SYMBOLS POSITION NAME AND DESCRIPTION
TIDR7 TIDR.7 MSB of the Idle Code (this bit is transmitted first)
TIDR0 TIDR.0 LSB of the Idle Code (this bit is transmitted last)
10.1.2 Per–Channel Code Insertion
The second method involves using the Transmit Channel Control Registers (TCC1/2/3/4) to determine
which of the 32 E1 channels should be overwritten with the code placed in the Transmit Channel
Registers (TC1 to TC32). This method is more flexible than the first in that it allows a different 8–bit
code to be placed into each of the 32 E1 channels.
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TC1 TO TC32: TRANSM IT CHANNEL REGISTERS (Address=60 to 7F Hex)
(for brevity, only channel one is shown; see Table 3-1 for other register address)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0 TC1 (60)
SYMBOLS POSITION NAME AND DESCRIPTION
C7 TC1.7 MSB of the Code (this bit is transmitted first)
C0 TC1.0 LSB of the Code (this bit is transmitted last)
TCC1/TCC2/TCC3/ TCC4: TRANSMIT CHANNEL CONTROL REGISTER
(Address=A0 to A3 Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 TCC1 (A0)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 TCC2 (A1)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 TCC3 (A2)
CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25 TCC4 (A3)
SYMBOLS POSITION NAME AND DESCRIPTION
CH1 - 32 TCC1.0 - 4.7 Transmit Code Insertion Control Bits
0 = do not insert data from the TC register into the transmit
data stream
1 = insert data from the TC register into the transmit data
stream
10.2 RECEIVE SIDE CODE GENERATION
On the receive side, the Receive Channel Control Registers (RCC1/2/3/4) are used to determine which of
the 32 E1 channels off of the E1 line and going to the backplane should be overwritten with the code
placed in the Receive Channel Registers (RC1 to RC32). This method allows a different 8–bit code to be
placed into each of the 32 E1 channels.
RC1 TO RC32: RECEIVE CHANNEL REGISTERS (Address=80 to 9F Hex)
(for brevity, only channel one is shown; see Table 3-1 for other register address)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0 RC1 (80)
SYMBOLS POSITION NAME AND DESCRIPTION
C7 RC1.7 MSB of the Code (this bit is sent first to the backplane)
C0 RC1.0 LSB of the Code (this bit is sent last to the backplane)
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RCC1/RCC2/RCC3/ RCC4: RECEIVE CHANNEL CONTROL REGISTER
(Address = A4 to A7 Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 RCC1 (A4)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 RCC2 (A5)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 RCC3 (A6)
CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25 RCC4 (A7)
SYMBOLS POSITION NAME AND DESCRIPTION
CH1 - 32 RCC1.0 - 4.7 Receive Code Insertion Control Bits
0 = do not insert data from the RC register into the receive data
stream
1 = insert data from the RC register into the receive data
stream
11. CLOCK BLOCKING REGI STERS
The Receive Channel blocking Registers (RCBR1 / RCBR2 / RCBR3 / RCBR4) and the Transmit
Channel Blocking Registers (TCBR1 / TCBR2 / TCBR3 / TCBR4) control RCHBLK and TCHBLK pins
on the DS21Q44 die, respectively. The RCHBLK and TCHBLK pins are not bonded out on the
DS21FT40 module. However, the Transmit Channel Blocking Registers have an alternate function that is
supported by the module. Via the CCR3.6 bit, the user has the option to use the TCBRs to determine on a
channel by channel basis, which signaling bits are to be inserted via the TSRs and which are to be sourced
from the TSER. If CCR3.6=1, then a zero in the TCBRs implies that signaling data is to be sourced from
and a one implies that signaling data for that channel is to be sourced from the Transmit Signaling (TS)
registers. See definition below. See the timing in Section 16 for an example. The Receive Channel
Blocking Registers provide no function for the DS21FT40 and should be cleared to zero.
TCBR1/TCBR2/TCBR3/TCBR4: DEFINITI ON WHEN CCR3.6=1
(MSB) (LSB)
CH20 CH4 CH19 CH3 CH18 CH2 CH17* CH1* TCBR1 (22)
CH24 CH8 CH23 CH7 CH22 CH6 CH21 CH5 TCBR2 (23)
CH28 CH12 CH27 CH11 CH26 CH10 CH25 CH9 TCBR3 (24)
CH32 CH16 CH31 CH15 CH30 CH14 CH29 CH13 TCBR4 (25)
*=CH1 and CH17 should be set to one to allow the internal TS1 register to create the CAS Multiframe
Alignment Word and Spare/Remote Alarm bits.
12. ELASTIC STORES OPERATION
Each framer in the DS21FT40 contains dual two–frame (512 bits) elastic stores, one for the receive
direction, and one for the transmit direction. These elastic stores have two main purposes. First, they can
be used to rate convert the E1 data stream to 1.544 Mbps (or a multiple of 1.544 Mbps) which is the T1
rate. Secondly, they can be used to absorb the differences in frequency and phase between the E1 data
stream and an asynchronous (i.e., not frequency locked) backplane clock which can be 1.544 MHz or
2.048 MHz. The backplane clock can burst at rates up to 8.192 MHz. Both elastic stores contain full
controlled slip capability which is necessary for this second purpose. Both elastic stores within a framer
are fully independent and no restrictions apply to the sourcing of the various clocks that are applied to
them. The transmit side elastic store can be enabled whether the receive elastic store is enabled or
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disabled and vice versa. Also, each elastic store can interface to either a 1.544 MHz or 2.048 MHz
backplane without regard to the backplane rate the other elastic store is interfacing.
Two mechanisms are available to the user for resetting the elastic stores. The Elastic Store Reset
(CCR6.0 & CCR6.1) function forces the elastic stores to a depth of one frame unconditionally. Data is
lost during the reset. The second method, the Elastic Store Align ( CCR5.5 & CCR5.6) forces the elastic
store depth to a minimum depth of half a frame only if the current pointer separation is already less then
half a frame. If a realignment occurs data is lost. In both mechanisms, independent resets are provided
for both the receive and transmit elastic stores.
12.1 RECEIVE SIDE
If the receive side elastic store is enabled (RCR2.1=1), then the user must provide either a 1.544 MHz
(RCR2.2 =0) or 2.048 MHz (RCR2.2=1) clock at the RSYSCLK pin. The user has the option of either
providing a frame/multiframe sync at the RSYNC pin (RCR1.5=1) or having the RSYNC pin provide a
pulse on frame/multiframe boundaries (RCR1.5=0). If the user wishes to obtain pulses at the frame
boundary, then RCR1.6 must be set to zero and if the user wishes to have pulses occur at the multiframe
boundary, then RCR1.6 must be set to one. If the elastic store is enabled, then either CAS (RCR1.7=0) or
CRC4 (RCR1.7=1) multiframe boundaries will be indicated via the RMSYNC output. If the user selects
to apply a 1.544 MHz clock to the RSYSCLK pin, then every fourth channel of the received E1 data will
be deleted and a F–bit position (which will be forced to one) will be inserted. Hence Channels 1, 5, 9, 13,
17, 21, 25, and 29 (timeslots 0, 4, 8, 12, 16, 20, 24, and 28) will be deleted from the received E1 data
stream). See Section 16 for timing details. If the 512–bit elastic buffer either fills or empties, a controlled
slip will occur. If the buffer empties, then a full frame of data (256–bits) will be repeated at RSER and
the SR1.4 and RIR.3 bits will be set to a one. If the buffer fills, then a full frame of data will be deleted
and the SR1.4 and RIR.4 bits will be set to a one.
12.2 TRANSMIT SIDE
The operation of the transmit elastic store is very similar to the receive side. The transmit side elastic
store is enabled via CCR3.7. A 1.544 MHz (CCR3.1=0) or 2.048 MHz (CCR3.1=1) clock can be applied
to the TSYSCLK input. The TSYSCLK can be a bursty clock with rates up to 8.192 MHz. If the user
selects to apply a 1.544 MHz clock to the TSYSCLK pin, then the data sampled at TSER will be ignored
every fourth channel. Hence Channels 1, 5, 9, 13, 17, 21, 25, and 29 (timeslots 0, 4, 8, 12, 16, 20, 24, and
28) will be ignored. The user must supply a 8 kHz frame sync pulse to the TSSYNC input. See Section
16 for timing details. Controlled slips in the transmit elastic store are reported in the SR2.0 bit and the
direction of the slip is reported in the RIR.6 and RIR.7 bits.
13. ADDITIONAL (Sa) AND INTERNATIONAL (Si ) BIT OPERATION
Each framer in the DS21FT40 provides for access to both the Sa and the Si bits via two different
methods. The first method involves using the internal RAF/RNAF and TAF/TNAF registers and is
discussed in Section 13.1. The second method, which is covered in Section 13.2, involves an expanded
version of the first method.
13.1 INTERNAL REGISTER SCHEME BASED ON DOUBLE–FRAME
On the receive side, the RAF and RNAF registers will always report the data as it received in the
Additional and International bit locations. The RAF and RNAF registers are updated with the setting of
the Receive Align Frame bit in Status Register 2 (SR2.6). The host can use the SR2.6 bit to know when
to read the RAF and RNAF registers. It has 250 us to retrieve the data before it is lost.
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On the transmit side, data is sampled from the TAF and TNAF registers with the setting of the Transmit
Align Frame bit in Status Register 2 (SR2.3). The host can use the SR2.3 bit to know when to update the
TAF and TNAF registers. It has 250 us to update the data or else the old data will be retransmitted. Data
in the Si bit position will be overwritten if the framer is programmed: (1) to source the Si bits from the
TSER pin, (2) in the CRC4 mode, or (3) have automatic E–bit insertion enabled. Data in the Sa bit
position will be overwritten if any of the TCR2.3 to TCR2.7 bits are set to one. Please see the register
descriptions for TCR1 and TCR2 and the Transmit Data Flow diagram in Section 16 for more details.
RAF: RECEIVE ALIGN FRAME REGISTER (Address=2F Hex)
(MSB) (LSB)
Si0011011
SYMBOLS POSITION NAME AND DESCRIPTION
Si RAF.7 International Bit.
0 RAF.6 Frame Alignment Signal Bit.
0 RAF.5 Frame Alignment Signal Bit.
1 RAF.4 Frame Alignment Signal Bit.
1 RAF.3 Frame Alignment Signal Bit.
0 RAF.2 Frame Alignment Signal Bit.
1 RAF.1 Frame Alignment Signal Bit
1 RAF.0 Frame Alignment Signal Bit.
RNAF: RECEIVE NON–ALIGN FRAME REGISTER (Address=1F Hex)
(MSB) (LSB)
Si 1 A Sa4 Sa5 Sa6 Sa7 Sa8
SYMBOLS POSITION NAME AND DESCRIPTION
Si RNAF.7 International Bit.
1 RNAF.6 Frame Non–Alignment Signal Bit.
A RNAF.5 Remote Alarm.
Sa4 RNAF.4 Additional Bit 4.
Sa5 RNAF.3 Additional Bit 5.
Sa6 RNAF.2 Additional Bit 6.
Sa7 RNAF.1 Additional Bit 7.
Sa8 RNAF.0 Additional Bit 8.
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TAF: TRANSMIT ALIGN FRAME REGISTER (Address=20 Hex)
(MSB) (LSB)
Si0011011
[Must be programmed with the 7 bit FAS word; the DS21FT40 does not automatically set these bits]
SYMBOLS POSITION NAME AND DESCRIPTION
Si TAF.7 International Bit.
0 TAF.6 Frame Alignment Signal Bit.
0 TAF.5 Frame Alignment Signal Bit.
1 TAF.4 Frame Alignment Signal Bit.
1 TAF.3 Frame Alignment Signal Bit.
0 TAF.2 Frame Alignment Signal Bit.
1 TAF.1 Frame Alignment Signal Bit.
1 TAF.0 Frame Alignment Signal Bit.
TNAF: TRANSMIT NON–ALIGN FRAME REGISTER (Address=21 Hex)
(MSB) (LSB)
Si 1 A Sa4 Sa5 Sa6 Sa7 Sa8
[Bit 2 must be programmed to one; the DS21FT40 does not automatically set this bit]
SYMBOLS POSITION NAME AND DESCRIPTION
Si TNAF.7 International Bit.
1 TNAF.6 Frame Non–Alignment Signal Bit.
A TNAF.5 Remote Alarm (used to transmit the alarm).
Sa4 TNAF.4 Additional Bit 4.
Sa5 TNAF.3 Additional Bit 5.
Sa6 TNAF.2 Additional Bit 6.
Sa7 TNAF.1 Additional Bit 7.
Sa8 TNAF.0 Additional Bit 8.
13.2 INTERNAL REGISTER SCHEME BASED ON CRC4 MULTIFRAME
On the receive side, there is a set of eight registers (RSiAF, RSiNAF, RRA, RSa4 to RSa8) that report the
Si and Sa bits as they are received. These registers are updated with the setting of the Receive CRC4
Multiframe bit in Status Register 2 (SR2.1). The host can use the SR2.1 bit to know when to read these
registers. The user has 2 ms to retrieve the data before it is lost. The MSB of each register is the first
received. Please see the register descriptions below and the Transmit Data Flow diagram in Section 16
for more details. On the transmit side, there is also a set of eight registers (TSiAF, TSiNAF, TRA, TSa4
to TSa8) that via the Transmit Sa Bit Control Register (TSaCR), can be programmed to insert both Si and
Sa data. Data is sampled from these registers with the setting of the Transmit Multiframe bit in Status
Register 2 (SR2.5). The host can use the SR2.5 bit to know when to update these registers. It has 2 ms to
update the data or else the old data will be retransmitted. The MSB of each register is the first bit
transmitted. Please see the register descriptions below and the Transmit Data Flow diagram in Section 16
for more details.
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REGISTER
NAME ADDRESS
(HEX) FUNCTION
RSiAF 58 The eight Si bits in the align frame.
RSiNAF 59 The eight Si bits in the non–align frame.
RRA 5A The eight reportings of the receive remote alarm (RA).
RSa4 5B The eight Sa4 reported in each CRC4 multiframe.
RSa5 5C The eight Sa5 reported in each CRC4 multiframe.
RSa6 5D The eight Sa6 reported in each CRC4 multiframe.
RSa7 5E The eight Sa7 reported in each CRC4 multiframe.
RSa8 5F The eight Sa8 reported in each CRC4 multiframe.
TSiAF 50 The eight Si bits to be inserted into the align frame.
TSiNAF 51 The eight Si bits to be inserted into the non–align frame.
TRA 52 The eight settings of remote alarm (RA).
TSa4 53 The eight Sa4 settings in each CRC4 multiframe.
TSa5 54 The eight Sa5 settings in each CRC4 multiframe.
TSa6 55 The eight Sa6 settings in each CRC4 multiframe.
TSa7 56 The eight Sa7 settings in each CRC4 multiframe.
TSa8 57 The eight Sa8 settings in each CRC4 multiframe.
TSaCR: TRANSM IT Sa BIT CONTROL REGISTER (Address=1C Hex)
(MSB) (LSB)
SiAF SiNAF RA Sa4 Sa5 Sa6 Sa7 Sa8
SYMBOLS POSITION NAME AND DESCRIPTION
SiAF TSaCR.7 International Bit in Align Frame Insertion Control Bit.
0=do not insert data from the TSiAF register into the transmit
data stream.
1=insert data from the TSiAF register into the transmit data
stream.
SiNAF TSaCR.6 International Bit in Non–Align Frame Insertion Control Bit.
0=do not insert data from the TSiNAF register into the transmit
data stream.
1=insert data from the TSiNAF register into the transmit data
stream.
RA TSaCR.5 Remote Alarm Insertion Control Bit.
0=do not insert data from the TRA register into the transmit
data stream.
1=insert data from the TRA register into the transmit data
stream.
Sa4 TSaCR.4 Additional Bit 4 Insertion Control Bit.
0=do not insert data from the TSa4 register into the transmit
data stream.
1=insert data from the TSa4 register into the transmit data
stream.
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SYMBOLS POSITION NAME AND DESCRIPTION
Sa5 TSaCR.3 Additional Bit 5 Insertion Control Bit.
0=do not insert data from the TSa5 register into the transmit
data stream.
1=insert data from the TSa5 register into the transmit data
stream.
Sa6 TSaCR.2 Additional Bit 6 Insertion Control Bit.
0=do not insert data from the TSa6 register into the transmit
data stream.
1=insert data from the TSa6 register into the transmit data
stream.
Sa7 TSaCR.1 Additional Bit 7 Insertion Control Bit.
0=do not insert data from the TSa7 register into the transmit
data stream.
1=insert data from the TSa7 register into the transmit data
stream.
Sa8 TSaCR.0 Additional Bit 8 Insertion Control Bit.
0=do not insert data from the TSa8 register into the transmit
data stream.
1=insert data from the TSa8 register into the transmit data
stream.
14. HDLC CONTROLLER FOR THE SA BI TS OR DS0
Each framer in the DS21FT40 has the ability to extract/insert data from/ into the Sa bit positions (Sa4 to
Sa8) or from/to any multiple of DS0 channels Each framer contains a complete HDLC controller and this
operation is covered in Section 14.1.
14.1 GENERAL OVERVIEW
Each framer contains a complete HDLC controller with 64–byte buffers in both the transmit and receive
directions. The HDLC controller performs all the necessary overhead for generating and receiving a
HDLC formatted message.
The HDLC controller automatically generates and detects flags, generates and checks the CRC check
sum, generates and detects abort sequences, stuffs and destuffs zeros (for transparency), and byte aligns to
the HDLC data stream.
There are eleven registers that the host will use to operate and control the operation of the HDLC
controller. A brief description of the registers is shown in Table 14-1.
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HDLC CONTROLLER REGISTER LIST Table 14-1
NAME FUNCTION
HDLC Control Register (HCR) general control over the HDLC and BOC
controllers
HDLC Status Register (HSR) key status information for both transmit and
receive directions
HDLC Interrupt Mask Register (HIMR) allows/stops status bits to/from causing an
interrupt
Receive HDLC Information Register
(RHIR)
status information on receive HDLC
controller
Receive HDLC FIFO Register (RHFR) access to 64–byte HDLC FIFO in receive
direction
Receive HDLC DS0 Control Register 1
(RDC1)
Receive HDLC DS0 Control Register 2
(RDC2)
controls the HDLC function when used on
DS0 channels
Transmit HDLC Information Register
(THIR)
status information on transmit HDLC
controller
Transmit BOC Register (TBOC) enables/disables transmission of BOC codes
Transmit HDLC FIFO Register (THFR) access to 64–byte HDLC FIFO in transmit
direction
Transmit HDLC DS0 Control Register 1
(TDC1)
Transmit HDLC DS0 Control Register 2
(TDC2)
controls the HDLC function when used on
DS0 channels
14.2 HDLC STATUS REGI STERS
Three of the HDLC controller registers (HSR, RHIR, and THIR) provide status information. When a
particular event has occurred (or is occurring), the appropriate bit in one of these three registers will be set
to a one. Some of the bits in these three status registers are latched and some are real time bits that are not
latched. Section 14.4 contains register descriptions that list which bits are latched and which are not.
With the latched bits, when an event occurs and a bit is set to a one, it will remain set until the user reads
that bit. The bit will be cleared when it is read and it will not be set again until the event has occurred
again. The real time bits report the current instantaneous conditions that are occurring and the history of
these bits is not latched.
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Like the other status registers in the framer, the user will always proceed a read of any of the three
registers with a write. The byte written to the register will inform the framer which of the latched bits the
user wishes to read and have cleared (the real time bits are not affected by writing to the status register).
The user will write a byte to one of these registers, with a one in the bit positions he or she wishes to read
and a zero in the bit positions he or she does not wish to obtain the latest information on. When a one is
written to a bit location, the read register will be updated with current value and it will be cleared. When
a zero is written to a bit position, the read register will not be updated and the previous value will be held.
A write to the status and information registers will be immediately followed by a read of the same
register. The read result should be logically AND’ed with the mask byte that was just written and this
value should be written back into the same register to insure that bit does indeed clear. This second write
step is necessary because the alarms and events in the status registers occur asynchronously in respect to
their access via the parallel port. This write–read–write (for polled driven access) or write–read (for
interrupt driven access) scheme al lows an external microcontroller or microprocessor to i ndividually poll
certain bits without disturbing the other bits in the register. This operation is key in controlling the
DS21FT40 with higher–order software languages.
Like the SR1 and SR2 status registers, the HSR register has the unique ability to initiate a hardware
interrupt via the INT* output pin. Each of the events in the HSR can be either masked or unmasked from
the interrupt pin via the HDLC Interrupt Mask Register (HIMR). Interrupts will force the INT* pin low
when the event occurs. The INT* pin will be allowed to return high (if no other interrupts are present)
when the user reads the event bit that caused the interrupt to occur.
14.3 BASIC OPERATI O N DETAILS
As a basic guideline for interpreting and sending HDLC messages, the following sequences can be
applied:
Receive a HDLC Message
1. Enable RPS interrupts.
2. Wait for interrupt to occur.
3. Disable RPS interrupt and enable either RPE, RNE, or RHALF interrupt.
4. Read RHIR to obtain REMPTY status.
A. If REMPTY=0, then record OBYTE, CBYTE, and POK bits and then read the FIFO
A1. If CBYTE=0 then skip to step 5
A2. If CBYTE=1 then skip to step 7
B. If REMPTY=1, then skip to step 6
5. Repeat step 4.
6. Wait for interrupt, skip to step 4.
7. If POK=0, then discard whole packet, if POK=1, accept the packet.
8. Disable RPE, RNE, or RHALF interrupt, enable RPS interrupt and return to step 1.
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Transmit a HDLC Message
1. Make sure HDLC controller is done sending any previous messages and is current sending flags by
checking that the FIFO is empty by reading the TEMPTY status bit in the THIR register.
2. Enable either the THALF or TNF interrupt.
3. Read THIR to obtain TFULL status.
A. If TFULL=0, then write a byte into the FIFO and skip to next step (special case occurs when
the last byte is to be written, in this case set TEOM=1 before writing the byte and then skip to
step 6)
B. If TFULL=1, then skip to step 5
4. Repeat step 3.
5. Wait for interrupt, skip to step 3.
6. Disable THALF or TNF interrupt and enable TMEND interrupt.
7. Wait for an interrupt, then read TUDR status bit to make sure packet was transmitted correctly.
14.4 HDLC REGISTER DESCRIPTI O N
HCR: HDLC CONTROL REGISTER (Address=B0 Hex)
(MSB) (LSB)
RHR TFS THR TABT TEOM TZSD TCRCD
SYMBOLS POSITION NAME AND DESCRIPTION
HCR.7 Not Assigned. Should be set to zero.
RHR HCR.6 Receive HDLC Reset. A 0 to 1 transition will reset the receive
HDLC controller. Must be cleared and set again for a
subsequent reset.
TFS HCR.5 Transmit Flag/Idle Select.
0 = 7Eh.
1 = FFh.
THR HCR.4 Transmit HDLC Reset. A 0 to 1 transition will reset the
transmit HDLC controller. Must be cleared and set again for a
subsequent reset.
TABT HCR.3 Transmit Abort. A 0 to 1 transition will cause the FIFO
contents to be dumped and one FEh abort to be sent followed
by 7Eh or FFh flags/idle until a new packet is initiated by
writing new data into the FIFO. Must be cleared and set again
for a subsequent abort to be sent.
TEOM HCR.2 Transmit End of Message. Should be set to a one just before
the last data byte of a HDLC packet is written into the transmit
FIFO at THFR. The HDLC controller will clear this bit when
the last byte has been transmitted.
TZSD HCR.1 Transmit Zero Stuffer Defeat. Overrides internal enable.
0 = enable the zero stuffer (normal operation).
1 = disable the zero stuffer.
TCRCD HCR.0 Transmit CRC Defeat.
0 = enable CRC generation (normal operation).
1 = disable CRC generation.
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HSR: HDLC STATUS REGISTER (Address=B1 Hex)
(MSB) (LSB)
RPE RPS RHALF RNE THALF TNF TMEND
SYMBOLS POSITION NAME AND DESCRIPTION
HSR.7 Not Assigned. Should be set to zero.
RPE HSR.6 Receive Packet End. Set when the HDLC controller detects
either the finish of a valid message (i.e., CRC check complete)
or when the controller has experienced a message fault such as
a CRC checking error, or an overrun condition, or an abort has
been seen. The setting of this bit prompts the user to read the
RHIR register for details.
RPS HSR.5 Receive Packet Start. Set when the HDLC controller detects
an opening byte. The setting of this bit prompts the user to
read the RHIR register for details.
RHALF HSR.4 Receive FIFO Half Full. Set when the receive 64–byte FIFO
fills beyond the half way point. The setting of this bit prompts
the user to read the RHIR register for details.
RNE HSR.3 Receive FIFO Not Empty. Set when the receive 64–byte FIFO
has at least one byte available for a read. The setting of this bit
prompts the user to read the RHIR register for details.
THALF HSR.2 Transmit FIFO Half Empty. Set when the transmit 64–byte
FIFO empties beyond the half way point. The setting of this
bit prompts the user to read the THIR register for details.
TNF HSR.1 Transmit FIFO Not Full. Set when the transmit 64–byte FIFO
has at least one byte available. The setting of this bit prompts
the user to read the THIR register for details.
TMEND HSR.0 Transmit Message End. Set when the transmit HDLC
controller has finished sending a message. The setting of this
bit prompts the user to read the THIR register for details.
NOTE:
The RPE, RPS, and TMEND bits are latched and will be cleared when read.
HIMR: HDLC INTERRUPT MASK REGISTER (Address=B2 Hex)
(MSB) (LSB)
RPE RPS RHALF RNE THALF TNF TMEND
SYMBOLS POSITION NAME AND DESCRIPTION
HIMR.7 Not Assigned. Should be set to zero.
RPE HIMR.6 Receive Packet End.
0 = interrupt masked.
1 = interrupt enabled.
RPS HIMR.5 Receive Packet Start.
0 = interrupt masked.
1 = interrupt enabled.
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SYMBOLS POSITION NAME AND DESCRIPTION
RHALF HIMR.4 Receive FIFO Half Full.
0 = interrupt masked.
1 = interrupt enabled.
RNE HIMR.3 Receive FIFO Not Empty.
0 = interrupt masked.
1 = interrupt enabled.
THALF HIMR.2 Transmit FIFO Half Empty.
0 = interrupt masked.
1 = interrupt enabled.
TNF HIMR.1 Transmit FIFO Not Full.
0 = interrupt masked.
1 = interrupt enabled.
TMEND HIMR.0 Transmit Message End.
0 = interrupt masked.
1 = interrupt enabled.
RHIR: RECEIVE HDLC INFORMATION REGISTER (Address=B3 Hex)
(MSB) (LSB)
RABT RCRCE ROVR RVM REMPTY POK CBYTE OBYTE
SYMBOLS POSITION NAME AND DESCRIPTION
RABT RHIR.7 Abort Sequence Detected. Set whenever the HDLC controller
sees 7 or more ones in a row.
RCRCE RHIR.6 CRC Error. Set when the CRC checksum is in error.
ROVR RHIR.5 Overrun. Set when the HDLC controller has attempted to
write a byte into an already full receive FIFO.
RVM RHIR.4 Valid Message. Set when the HDLC controller has detected
and checked a complete HDLC packet.
REMPTY RHIR.3 Empty. A real–time bit that is set high when the receive FIFO
is empty.
POK RHIR.2 Packet OK. Set when the byte available for reading in the
receive FIFO at RHFR is the last byte of a valid message (and
hence no abort was seen, no overrun occurred, and the CRC
was correct).
CBYTE RHIR.1 Closing Byte. Set when the byte available for reading in the
receive FIFO at RFDL is the last byte of a message (whether
the message was valid or not).
OBYTE RHIR.0 Opening Byte. Set when the byte available for reading in the
receive FIFO at RHFR is the first byte of a message.
NOTE:
The RABT, RCRCE, ROVR, and RVM bits are latched and will be cleared when read.
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RHFR: RECEIVE HDLC FIFO REGISTER (Address=B4 Hex)
(MSB) (LSB)
HDLC7 HDLC6 HDLC5 HDLC4 HDLC3 HDLC2 HDLC1 HDLC0
SYMBOLS POSITION NAME AND DESCRIPTION
HDLC7 RHFR.7 HDLC Data Bit 7. MSB of a HDLC packet data byte.
HDLC6 RHFR.6 HDLC Data Bit 6.
HDLC5 RHFR.5 HDLC Data Bit 5.
HDLC4 RHFR.4 HDLC Data Bit 4.
HDLC3 RHFR.3 HDLC Data Bit 3.
HDLC2 RHFR.2 HDLC Data Bit 2.
HDLC1 RHFR.1 HDLC Data Bit 1.
HDLC0 RHFR.0 HDLC Data Bit 0. LSB of a HDLC packet data byte.
THIR: TRANSM IT HDLC INFORMATION REGISTER (Address=B6 Hex)
(MSB) (LSB)
–––––EMPTYTFULLUDR
SYMBOLS POSITION NAME AND DESCRIPTION
THIR.7 Not Assigned. Could be any value when read.
THIR.6 Not Assigned. Could be any value when read.
THIR.5 Not Assigned. Could be any value when read.
THIR.4 Not Assigned. Could be any value when read.
THIR.3 Not Assigned. Could be any value when read.
TEMPTY THIR.2 Transmit FIFO Empty. A real–time bit that is set high when
the FIFO is empty.
TFULL THIR.1 Transmit FIFO Full. A real–time bit that is set high when the
FIFO is full.
UDR THIR.0 Underrun. Set when the transmit FIFO unwantedly empties
out and an abort is automatically sent.
NOTE:
The UDR bit is latched and will be cleared when read.
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THFR: TRANSM IT HDLC FIFO REGISTER (Address=B7 Hex)
(MSB) (LSB)
HDLC7 HDLC6 HDLC5 HDLC4 HDLC3 HDLC2 HDLC1 HDLC0
SYMBOLS POSITION NAME AND DESCRIPTION
HDLC7 THFR.7 HDLC Data Bit 7. MSB of a HDLC packet data byte.
HDLC6 THFR.6 HDLC Data Bit 6.
HDLC5 THFR.5 HDLC Data Bit 5.
HDLC4 THFR.4 HDLC Data Bit 4.
HDLC3 THFR.3 HDLC Data Bit 3.
HDLC2 THFR.2 HDLC Data Bit 2.
HDLC1 THFR.1 HDLC Data Bit 1.
HDLC0 THFR.0 HDLC Data Bit 0. LSB of a HDLC packet data byte.
RDC1: RECEIVE HDLC DS0 CONTROL REGISTER 1 (Address=B8 Hex)
(MSB) (LSB)
RHS RSaDS RDS0M RD4 RD3 RD2 RD1 RD0
SYMBOLS POSITION NAME AND DESCRIPTION
RHS RDC1.7 Receive HDLC source
0 = Sa bits defined by RCR2.3 to RCR2.7.
1 = Sa bits or DS0 channels defined by RDC1 (see bits defined
below).
RSaDS RDC1.6 Receive Sa Bit / DS0 Select.
0 = route Sa bits to the HDLC controller. RD0 to RD4 defines
which Sa bits are to be routed. RD4 corresponds to Sa4, RD3
to Sa5, RD2 to Sa6, RD1 to Sa7 and RD0 to Sa8.
1 = route DS0 channels into the HDLC controller. RDC1.5 is
used to determine how the DS0 channels are selected.
RDS0M RDC1.5 DS0 Selection Mode.
0 = utilize the RD0 to RD4 bits to select which single DS0
channel to use.
1 = utilize the RCHBLK control registers to select which DS0
channels to use. This option is not applicable for the
DS21FT40.
RD4 RDC1.4 DS0 Channel Select Bit 4. MSB of the DS0 channel select.
RD3 RDC1.3 DS0 Channel Select Bit 3.
RD2 RDC1.2 DS0 Channel Select Bit 2.
RD1 RDC1.1 DS0 Channel Select Bit 1.
RD0 RDC1.0 DS0 Channel Select Bit 0. LSB of the DS0 channel select.
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RDC2: RECEIVE HDLC DS0 CONTROL REGISTER 2 (Address=B9 Hex)
(MSB) (LSB)
RDB8 RDB7 RDB6 RDB5 RDB4 RDB3 RDB2 RDB1
SYMBOLS POSITION NAME AND DESCRIPTION
RDB8 RDC2.7 DS0 Bit 8 Suppress Enable. MSB of the DS0. Set to one to
stop this bit from being used.
RDB7 RDC2.6 DS0 Bit 7 Suppress Enable. Set to one to stop this bit from
being used.
RDB6 RDC2.5 DS0 Bit 6 Suppress Enable. Set to one to stop this bit from
being used.
RDB5 RDC2.4 DS0 Bit 5 Suppress Enable. Set to one to stop this bit from
being used.
RDB4 RDC2.3 DS0 Bit 4 Suppress Enable. Set to one to stop this bit from
being used.
RDB3 RDC2.2 DS0 Bit 3 Suppress Enable. Set to one to stop this bit from
being used.
RDB2 RDC2.1 DS0 Bit 2 Suppress Enable. Set to one to stop this bit from
being used.
RDB1 RDC2.0 DS0 Bit 1 Suppress Enable. LSB of the DS0. Set to one to
stop this bit from being used.
TDC1: TRANSM IT HDLC DS0 CONTROL REGISTER 1 (Address = BA Hex)
(MSB) (LSB)
THE TSaDS TDS0M TD4 TD3 TD2 TD1 TD0
SYMBOLS POSITION NAME AND DESCRIPTION
THE TDC1.7 Transmit HDLC Enable.
0 = disable HDLC controller (no data inserted by HDLC
controller into the transmit data stream)
1 = enable HDLC controller to allow insertion of HDLC data
into either the Sa position or multiple DS0 channels as defined
by TDC1 (see bit definitions below).
TSaDS TDC1.6 Transmit Sa Bit / DS0 Select. This bit is ignored if TDC1.7 is
set to zero.
0 = route Sa bits from the HDLC controller. TD0 to TD4
defines which Sa bits are to be routed. TD4 corresponds to
Sa4, TD3 to Sa5, TD2 to Sa6, TD1 to Sa7 and TD0 to Sa8.
1 = route DS0 channels from the HDLC controller. TDC1.5 is
used to determine how the DS0 channels are selected.
TDS0M TDC1.5 DS0 Selection Mode.
Not applicable for the DS21FT40. Should be cleared to zero.
DS21FT40
64 of 87
SYMBOLS POSITION NAME AND DESCRIPTION
TD4 TDC1.4 DS0 Channel Select Bit 4. MSB of the DS0 channel select.
TD3 TDC1.3 DS0 Channel Select Bit 3.
TD2 TDC1.2 DS0 Channel Select Bit 2.
TD1 TDC1.1 DS0 Channel Select Bit 1.
TD0 TDC1.0 DS0 Channel Select Bit 0. LSB of the DS0 channel select.
TDC2: TRANSMIT HDLC DS0 CONTROL REGISTER 2 (Address = BB Hex)
(MSB) (LSB)
TDB8 TDB7 TDB6 TDB5 TDB4 TDB3 TDB2 TDB1
SYMBOLS POSITION NAME AND DESCRIPTION
TDB8 TDC2.7 DS0 Bit 8 Suppress Enable. MSB of the DS0. Set to one to
stop this bit from being used.
TDB7 TDC2.6 DS0 Bit 7 Suppress Enable. Set to one to stop this bit from
being used.
TDB6 TDC2.5 DS0 Bit 6 Suppress Enable. Set to one to stop this bit from
being used.
TDB5 TDC2.4 DS0 Bit 5 Suppress Enable. Set to one to stop this bit from
being used.
TDB4 TDC2.3 DS0 Bit 4 Suppress Enable. Set to one to stop this bit from
being used.
TDB3 TDC2.2 DS0 Bit 3 Suppress Enable. Set to one to stop this bit from
being used.
TDB2 TDC2.1 DS0 Bit 2 Suppress Enable. Set to one to stop this bit from
being used.
TDB1 TDC2.0 DS0 Bit 1 Suppress Enable. LSB of the DS0. Set to one to
stop this bit from being used.
15. INTERLEAVED PCM BUS OPERATION
In many architectures, the outputs of individual framers are combined into higher speed serial buses to
simplify transport across the system. The DS21FT40 can be configured to allow each framer’s data and
signaling busses to be multiplexed into higher speed data and signaling busses eliminating external
hardware saving board space and cost. In particular, t he four framers associated with each DS21Q44 die
can be combined.
The interleaved PCM bus option supports two bus speeds and interleave modes. The 4.096 MHz bus
speed allows two framers to share a common bus. The 8.192 MHz bus speed allows all four of the
framers for each DS21Q44 die to share a common bus. Framers can i nterl eave thei r data eit her on byte or
frame boundaries. Framers that share a common bus must be configured through software and require
several device pins to be connected together externally (see figures 15-1 & 15-2). Each framer’s elastic
stores must be enabled and configured for 2.048 MHz operation. The signal RSYNC must be configured
as an input on each framer.
DS21FT40
65 of 87
For all bus configurations, one framer will be configured as the master device and the remaining framers
on the shared bus will be configured as slave devices. Refer to the IBO register description below for
more detail. In the 4.096 MHz bus configuration there is one master and one slave per bus. Figure 15-1
shows the DS21Q44 configured to support two 4.096 MHz buses. Bus 1 consists of framers 0 and 1. Bus
2 consists of framers 2 and 3. Framers 0 and 2 are programmed as master devices. Framers 1 and 3 are
programmed as slave devices. In the 8.192 MHz bus configuration there is one master and three slaves.
Figure 15-2 shows the DS21Q44 configured to support a 8.192 MHz bus. Framer 0 is programmed as the
master device. Framers 1, 2 and 3 are programmed as slave devices. Consult timing diagrams in section
16 for additional information.
When using the frame interleave m ode, all framers th at share an i nterleaved bus m ust have recei ve signals
(RPOS & RNEG) that are synchronous with each other. The received signals must originate from the
same clock reference. This restriction does not apply in the byte interleave mode.
IBO: INTERLEAVE BUS OPERATION REGISTER (Address = B5 Hex)
(MSB) (LSB)
IBOEN INTSEL MSEL0 MSEL1
SYMBOLS POSITION NAME AND DESCRIPTION
IBO.7 Not Assigned. Should be set to 0.
IBO.6 Not Assigned. Should be set to 0.
IBO.5 Not Assigned. Should be set to 0.
IBO.4 Not Assigned. Should be set to 0.
IBOEN IBO.3 Interleave Bus Operation Enable
0 = Interleave Bus Operation disabled.
1 = Interleave Bus Operation enabled.
INTSEL IBO.2 Interleave Type Select
0 = Byte interleave.
1 = Frame interleave.
MSEL0 IBO.1 Master Device Bus Select Bit 0 See table 15-1.
MSEL1 IBO.0 Master Device Bus Select Bit 1 See table 15-1.
Master Device Bus Select Table 15-1
MSEL1 MSEL0 Function
0 0 Slave device.
0 1 Master device with 1 slave device (4.096 MHz bus rate)
1 0 Master device with 3 slave devices (8.192 MHz bus rate)
11Reserved
DS21FT40
66 of 87
4.096 M Hz I nter l eaved Bus External Pi n Connection Example Figure 15-1
RSYSCLK0
TSYSCLK0
RSER0
TSER0
RSYNC0
TSSYNC0
FRAMER 0
RSYSCLK1
TSYSCLK1
RSER1
TSER1
RSYNC1
TSSYNC1
FRAMER 1
SYSCLK
SYNC INPUT
RSER
TSER
Bus 1 Bus 2
RSYSCLK2
TSYSCLK2
RSER2
TSER2
RSYNC2
TSSYNC2
FRAMER 2
RSYSCLK3
TSYSCLK3
RSER3
TSER3
RSYNC3
TSSYNC3
FRAMER 3
SYSCLK
SYNC INPUT
RSER
TSER
8.192 M Hz I nter l eaved Bus External Pi n Connection Example Figure 15-2
RSYSCLK0
TSYSCLK0
RSER0
TSER0
RSYNC0
TSSYNC0
FRAMER 0
RSYSCLK1
TSYSCLK1
RSER1
TSER1
RSYNC1
TSSYNC1
FRAMER 1
RSYSCLK2
TSYSCLK2
RSER2
TSER2
RSYNC2
TSSYNC2
FRAMER 2
RSYSCLK3
TSYSCLK3
RSER3
TSER3
RSYNC3
TSSYNC3
FRAMER 3
SYSCLK
SYNC INPUT
RSER
TSER
DS21FT40
67 of 87
16. TIMING DIAGRAMS
Receive Side Timing Figure 16-1
12
3456 7 8 910111213141516
FRAME#
112
345614 15 16
2
RSYNC /
RFSYNC
RSYNC
Notes:
1. RSYNC in the frame mode (RCR1.6 = 0)
2. RSYNC in the multiframe mode (RCR1.6 = 1)
3. This diagram assumes the CAS MF begins with the FAS word
RECEIVE SIDE BOUNDARY TIMING (wi t h el astic store disabl ed) Figure 16-2
RCLK
RSYNC
Notes:
1. There is a 6 RCLK delay from RPOS, RNEG to RSER
2. Shown is a non-align frame boundary
LSBMSB MSB CHANNEL 2
RSER CHANNEL 32 Si 1 A Sa4
CHANNEL 1
Sa5 Sa6 Sa7 Sa8
LSB MSB
CHANNEL 2
Si 1 A Sa4
CHANNEL 1
Sa5 Sa6 Sa7 Sa8
RPOS, RNEG 1LSB
DS21FT40
68 of 87
RECEIVE SIDE 1. 544 MHz BOUNDARY TIMING (wi th elastic store enabl ed)
Figure 16-3
RSER LSB MSB FMSB
LSB
RSYNC
RSYSCLK
RSYNC
1
2
3
CHANNEL 23/31 CHANNEL 24/32 CHANNEL 1/2
Notes:
1. Data from the E1 channels 1, 5, 9, 13, 17, 21, 25, and 29 is dropped (channel 2 from the E1 link is
mapped to channel 1 of the T1 link, etc.) and the F-bit position is added (forced to one)
2. RSYNC is in the output mode (RCR1.5 = 0)
3. RSYNC is in the input mode (RCR1.5 = 1)
RECEIVE SIDE 2. 048 MHz BOUNDARY TIMING (wi th elastic store enabl ed)
Figure 16-4
RSER LSB MSB LSB CHANNEL 1
RSYNC
RSYSCLK
RSYNC
CHANNEL 31 CHANNEL 32
1
2
MSB
Notes:
1. RSYNC is in the output mode (RCR1.5 = 0)
2. RSYNC is in the input mode (RCR1.5 = 1)
DS21FT40
69 of 87
RECEIVE SIDE I NTERLEAVED BUS OPERATION BYTE MODE TIMING
Figure 16-5
RSER LSB
SYSCLK
RSYNC
FRAMER 3, CHANNEL 32 MSB LSB
FRAMER 0, CHANNEL 1 MSB LSB
FRAMER 1, CHANNEL 1
Notes:
1. 4.096 MHz bus configuration.
2. 8.192 MHz bus configuration.
3. RSYNC is in the input mode (RCR1.5 = 1).
3
RSER
RSYNC
RSIG
FR1 CH32 FR0 CH1 FR1 CH1 FR0 CH2 FR1 CH2
RSER FR2 CH32 FR3 CH32 FR0 CH1 FR1 CH1 FR2 CH1 FR3 CH1 FR0 CH2 FR1 CH2 FR2 CH2 FR3 CH2
FR1 CH32 FR0 CH1 FR1 CH1 FR0 CH2 FR1 CH2
1
1
2
BIT DETAIL
RECEIVE SIDE I NTERLEAVED BUS OPERATION FRAM E MODE TIMING
Figure 16-6
RSER LSB
SYSCLK
RSYNC
FRAMER 3, CHANNEL 32 MSB LSB
FRAMER 0, CHANNEL 1 MSB LSB
FRAMER 0, CHANNEL 2
Notes:
1. 4.096 MHz bus configuration.
2. 8.192 MHz bus configuration.
3. RSYNC is in the input mode (RCR1.5 = 1).
3
RSER
RSYNC
FR1 CH1-32 FR0 CH1-32 FR1 CH1-32
RSER FR2 CH1-32 FR3 CH1-32 FR0 CH1-32 FR1 CH1-32 FR2 CH1-32 FR3 CH1-32 FR0 CH1-32 FR1 CH1-32 FR2 CH1-32 FR3 CH1-32
FR0 CH1-32 FR1 CH1-32
1
2
BIT DETAIL
DS21FT40
70 of 87
TRANSMIT SIDE TIMING Figure 16-7
12
3456 7 8 910111213141516FRAME#1
TSYNC
TSYNC
12
345614 15 16
2
Notes:
1. TSYNC in the frame mode (TCR1.1 = 0)
2. TSYNC in the multiframe mode (TCR1.1 = 1)
3. This diagram assumes both the CAS MF and the CRC4 begin with the align frame
TRANSMIT SIDE TIMING Figure 13.5
TRANSMIT SIDE BOUNDARY TIMING (with elastic store disabl ed)
Figure 16-8
LSB MSB
CHANNEL 2
CHANNEL 1
2
3
TCLK
TSYNC
TSYNC
ASa4 Sa5 Sa6 Sa7 Sa8
Notes:
1. There is a 5 TCLK delay from TSER to TPOS and TNEG
2. TSYNC is in the input mode (TCR1.0 = 0)
3. TSYNC is in the output mode (TCR1.0 = 1)
4. Shown is a non-align frame boundary
TPOS, TNEG Si 1
LSB MSB LSB MSBA Sa4 Sa5 Sa6 Sa7 Sa8
TSER Si 1 CHANNEL 1
MSB
CHANNEL 32
1
DS21FT40
71 of 87
TRANSMIT SIDE 1. 544 MHz BOUNDARY TIMING (wi t h el astic store enabled)
Figure 16-9
TSER LSB MSB LSB CHANNEL 1
TSYSCLK
TSSYNC
CHANNEL 23 CHANNEL 24
Notes:
1. The F-bit position is ignored by the DS21FT40
MSB
F-Bit
TRANSMIT SIDE 2. 048 MHz BOUNDARY TIMING (wi t h el astic store enabled)
Figure 16-10
TSER LSB MSB LSB CHANNEL 1
TSYSCLK
TSSYNC
CHANNEL 31 CHANNEL 32 MSB
DS21FT40
72 of 87
TRANSMIT SIDE INTERLEAVED BUS OPERATION BYTE MODE TI MING
Figure 16-11
TSER LSB
SYSCLK
TSSYNC
FRAMER 3, CHANNEL 32 MSB LSB
FRAMER 0, CHANNEL 1 MSB LSB
FRAMER 1, CHANNEL 1
Notes:
1. 4.096 MHz bus configuration.
2. 8.192 MHz bus configuration.
TSER
TSSYNC
TSER FR2 CH32 FR3 CH32 FR0 CH1 FR1 CH1 FR2 CH1 FR3 CH1 FR0 CH2 FR1 CH2 FR2 CH2 FR3 CH2
1
2
BIT DETAIL
FR1 CH32 FR0 CH1 FR1 CH1 FR0 CH2 FR1 CH2
TRANSMIT SIDE INTERLEAVED BUS OPERATION FRAME MODE TIMING
Figure 16-12
TSER LSB
SYSCLK
TSSYNC
FRAMER 3, CHANNEL 32 MSB LSB
FRAMER 0, CHANNEL 1 MSB LSB
FRAMER 0, CHANNEL 2
Notes:
1. 4.096 MHz bus configuration.
2. 8.192 MHz bus configuration.
TSER
TSSYNC
FR1 CH1-32 FR0 CH1-32 FR1 CH1-32
TSER FR2 CH1-32 FR3 CH1-32 FR0 CH1-32 FR1 CH1-32 FR2 CH1-32 FR3 CH1-32 FR0 CH1-32 FR1 CH1-32 FR2 CH1-32 FR3 CH1-32
FR0 CH1-32 FR1 CH1-32
1
2
BIT DETAIL
DS21FT40
73 of 87
DS21FT40 FRAMER SYNCHRONIZATION FLOWCHART Figure 16-13
FAS Resync
Criteria Met
Check for >=915
Out of 1000
CRC4 Word Errors
8ms
Time
Out
RLOS = 1
Set FASRC
(RIR.1)
CAS Resync
Criteria Met;
Set CASRC
(RIR.0)
FAS Search
FASSA = 1
FAS Sync
Criteria Met
FASSA = 0
CAS Sync
Criteria Met
CASSA = 0
If CRC4 is on
(CCR1.0 = 1)
RLOS = 1
If CAS is on
(CCR1.3 = 0)
Power Up
Increment CRC4
Sync Counter;
CRC4SA = 0
CRC4 Resync
Criteria Met
(RIR.2)
CAS Multiframe Search
(if enabled via CCR1.3)
CASSA = 1
CRC4 Multiframe Search
(if enabled via CCR1.0)
CRC4SA = 1
Resync if
RCR1.0 = 0
Check for FAS
Framing Error
(depends on RCR1.2)
Check for CAS
MF Word Error
Sync Declared
RLOS = 0
CRC4 Sync Criteria
Met; CRC4SA = 0;
Reset CRC4
Sync Counter
DS21FT40
74 of 87
DS21FT40 TRANSMIT DATA FLOW Figure 16-14
Si Bit Insertion
Control
(TCR1.3)
Timeslot 0
Pass-Through
(TCR1.6)
E-Bit Generat ion
(TCR2.1)
Sa Bit Insertion
Control (TCR2.3
thru TCR2.7)
Idle Code / Channel
Insertion Control via
TIR1/2/3/4
Transmit Unframed All
Ones (TCR1.4) or
Auto AI S (CCR2.5)
Code Word
Generation
CRC4 Enable
(CCR1.4)
TAF
TNAF.5-7
TLINK
TS1 to TS16
TIDR
TPOS,
TNEG
01
01
10
01
10
01
01
10
AIS
Generation
Transmit Signaling
All Ones
(TCR1.2)
= Register
= Device Pin
= Selector
KEY:
TCBR1/2/3/4
RSER
(note #1 )
CCR3.6
TCR1.5
Signaling Bit
Insertion Control
TIR Function Select
(CCR3.5)
AIS
Generation
01
NOTES:
1. TCLK should be tied to RCLK and TSYNC should be tied to RFSYNC for
data to be properly sourced from RSER.
2. Auto Remote Alarm if enabled will only overwrite bit 3 of timeslot 0 in the
Not Align Frames if the alarm needs to be sent.
Sa Bit Insertion
Control Register
(TSaCR)
10
TSa4 to T Sa8
TRA
TSiNAF
TSiAF
CRC4 Multiframe
Alignment Word
Generation (CCR.4)
Receive Side
CRC4 Error
Detector
01
Auto Re mote Al a rm
Generation (CCR2.4)
Per-Channel Code
Generation
(TCC1/2/3/4)
01
TC1 to TC32
HDLC
ENGINE
DS0 Data
Sou r ce MUX
(TDC1/2)
01
TSER
&
TDATA
TAF/TNAF Bit
MUX
01
TNAF.0-4
Sa Data Sour ce
MUX
(TDC1)
01
DS0 Monitor
TSIG
Hardware
Signaling
Insertion (CCR3 .2)
01
DS21FT40
75 of 87
17. OPERATING PARAMETERS
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Non-Supply Pin Relative to Ground –1.0V to +5.5V
Supply Voltage –.3V to +3.63V
Operating Temperature for DS21FT40 0ºC to 70ºC
Operating Temperature for DS21FT40N –40ºC to +85ºC
Storage Temperature –55ºC to +125ºC
Soldering Temperature See J-STD-020A
* This is a stress rating only and functional operation of the device at these or any other conditions above
those indicated in the operation sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDI TI ONS (0ºC to 70ºC for DS21FT40;
0ºC to +85ºC for DS21FT40N)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Logic 1 VIH 2.0 5.5 V
Logic 0 VIL –0.3 +0.8 V
Supply VDD 2.97 3.63 V
CAPACITANCE (t
A
=25ºC)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Input Capacitance CIN 5pF
Output Capacitance COUT 7pF
DC CHARACTERISTICS (0ºC to 70ºC; VDD = 2.97 to 3.63V for DS21FT40;
-40ºC to +85ºC; VDD = 2.97 to 3.63V for DS21Q44N)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Supply Current @ 3.3V IDD 75 mA 1
Input Leakage IIL –1.0 +1.0 µA 2
Output Leakage ILO 1.0 µA 3
Output Current (2.4V) IOH –1.0 mA
Output Current (0.4V) IOL +4.0 mA
NOTES:
1. TCLK=RCLK=TSYSCLK=RSYSCLK=2.048 MHz; outputs open circuited.
2. 0.0V < V IN < V DD .
3. Applied to INT* when 3–stated.
DS21FT40
76 of 87
AC CHARACTERISTICS – MULTIPLEXED
PARALLEL PORT (MUX=1) (0ºC to 70ºC; VDD = 2.97 to 3.63V for DS21FT40
–40ºC to +85ºC; VDD = 2.97 to 3.63V for DS21FT40N)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Cycle Time t CYC 200 ns
Pulse Width, DS low or
RD* high PW EL 100 ns
Pulse Width, DS high or
RD* low PW EH 100 ns
Input Rise/Fall times t R , t F20 ns
R/W* Hold Time t RWH 10 ns
R/W* Set Up time
before DS high t RWS 50 ns
CS1*, CS2*, CS3*,
FSO or FS1 Set Up time
before DS, WR* or
RD* active
t CS 20 ns
CS1*, CS2*, CS3*,
FSO or FS1 Hold time t CH 0ns
Read Data Hold time t DHR 10 50 ns
Write Data Hold time t DHW 0ns
Muxed Address valid to
AS or ALE fall t ASL 15 ns
Muxed Address Hold
time t AHL 10 ns
Delay time DS, WR* or
RD* to AS or ALE rise t ASD 20 ns
Pulse Width AS or ALE
high PW ASH 30 ns
Delay time, AS or ALE
to DS, WR* or RD* t ASED 10 ns
Output Data Delay time
from DS or RD* t DDR 20 80 ns
Data Set Up time t DSW 50 ns
(see Figures 17-1 to 17-3 for details)
DS21FT40
77 of 87
AC CHARACTERISTICS – NON–MULTIPLEXED
PARALLEL PORT (MUX=0 ) (0ºC to 70ºC; VDD = 2.97 to 3.63V for DS21FT40;
–40ºC to +85ºC; VDD = 2.97 to 3.63V for DS21FT40N)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Set Up Time for A0 to
A7, FS0 or FS1 Valid to
CS1*, CS2*, CS3*
Active
t 10ns
Set Up Time for CS1*,
CS2*, CS3* Active to
either RD*, WR*, or
DS* Active
t 20ns
Delay Time from either
RD* or DS* Active to
Data Valid
t 375 ns
Hold Time from either
RD*, WR*, or DS*
Inactive to CS1*, CS2*,
CS3* Inactive
t 40ns
Hold Time from CS1*,
CS2*, CS3* Inactive to
Data Bus 3–state
t 5520ns
Wait Time from either
WR* or DS* Active to
Latch Data
t 675 ns
Data Set Up Time to
either WR* or DS*
Inactive
t 710 ns
Data Hold Time from
either WR* or DS*
Inactive
t 810 ns
Address Hold from
either WR* or DS*
inactive
t 910 ns
See Figures 17–4 to 17-7 for details.
DS21FT40
78 of 87
AC CHARACTERISTI CS – RECEIVE SIDE
(0ºC to 70ºC; VDD = 2.97 to 3.63V for DS21FT40;
–40ºC to +85ºC; VDD = 2.97 to 3.63V for DS21FT40N)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
RCLK Period t CP 488 ns
RCLK Pulse Width t CH
t CL
75
75 ns
ns
RSYSCLK Period t SP
t SP
122
122 648
488 ns
ns 1
2
RSYSCLK Pulse Width t SH t SL 50
50 ns
ns
RSYNC Set Up to
RSYSCLK Falling t SU 20 t SH –5 ns
RSYNC Pulse Width t PW 50 ns
RPOS/RNEG Set UP to
RCLK Falling t SU 20 ns
RPOS/RNEG Hold From
RCLK Falling t HD 20 ns
RSYSCLK/RCLKI Rise
and Fall Times t R , t F25 ns
Delay RCLK to RSER
Valid t D1 50 ns
Delay RCLK to RSYNC t D2 50 ns
Delay RSYSCLK to RSER
Valid t D3 50 ns
Delay RSYSCLK to
RMSYNC, RSYNC t D4 50 ns
See Figures 17-8 to 17-10 for details.
NOTES:
1. RSYSCLK = 1.544 MHz.
2. RSYSCLK = 2.048 MHz.
DS21FT40
79 of 87
AC CHARACTERISTICS – TRANSMIT SI DE
(0ºC to 70ºC; VDD = 2.97 to 3.63V for DS21FT40;
–40ºC to +85ºC; ; VDD = 2.97 to 3.63V for DS21FT40N)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
TCLK Period t CP 488 ns
TCLK Pulse Width t CH
t CL
75
75 ns
ns
TCLKI Pulse Width t LH
t LL
75
75 ns
ns
TSYSCLK Period t SP
t SP
122
122 648
448 ns
ns 1
2
TSYSCLK Pulse Width t SH
t SL
50
50 ns
ns
TSYNC or TSSYNC Set
Up to TCLK or TSYSCLK
falling
t SU 20 t CH –5
or
t SH –5
ns
TSYNC or TSSYNC Pulse
Width t PW 50 ns
TSER Set Up to TCLK,
TSYSCLK Falling t SU 20 ns
TSER Hold from TCLK,
TSYSCLK Falling t HD 20 ns
TCLK or TSYSCLK Rise
and Fall Times t R , t F25 ns
Delay TCLK to TPOS,
TNEG Valid t DD 50 ns
Delay TCLK to TSYNC t D2 50 ns
See Figures 17–11 to 17–13 for details.
NOTES:
1. TSYSCLK = 1.544 MHz.
2. TSYSCLK = 2.048 MHz.
DS21FT40
80 of 87
INTEL BUS READ AC TIMING (BTS=0 / MUX = 1) Figure 17-1
ASH
PW
tCYC
tASD
tASD PW
PW
EH
EL
t
t
t
t
t
t
AHL
CH
CS
ASL
ASED
CS*
AD0-AD7
DHR
tDDR
ALE
RD*
WR*
INTEL BUS WRITE TIMING (BTS=0 / MUX=1) Figure 17-2
ASH
PW
tCYC
tASD
tASD PW
PW
EH
EL
t
t
t
t
t
t
t
AHL DSW
DHW
CH
CS
ASL
ASED
CS*
AD0-AD7
RD*
WR*
ALE
DS21FT40
81 of 87
MOTOROLA BUS AC TIMING (BTS = 1 / MUX = 1) Figure 17-3
tASD
ASH
PW
t
t
ASL
AHL tCS
tASL
t
t
t
DSW
DHW
tCH
tt
t
DDR DHR
RWH
tASED PWEH
tRWS
AHL
PWEL tCYC
AS
DS
AD0-AD7
(write)
AD0-AD7
(read)
R/W*
CS*
INTEL BUS READ AC TIMING (BTS=0 / MUX=0) Figure 17-4
Address Valid
Data Valid
A0 to A7
D0 to D7
WR*
CS*
RD*
0ns min.
0ns min.
75ns max.
0ns min.
5ns min. / 20ns max.
t1
t2 t3 t4
t5
DS21FT40
82 of 87
INTEL BUS WRITE AC TIMING (BTS=0 / MUX=0) Figure 17-5
Address ValidA0 to A7
D0 to D7
RD*
CS*
WR*
0ns min.
0ns min.
75ns min.
0ns min.
10ns
min. 10ns
min.
t1
t2 t6 t4
t7 t8
MOTOROLA BUS READ AC TIMING (BTS=1 / MUX=0) Figure 17-6
Address Valid
Data Valid
A0 to A7
D0 to D7
R/W*
CS*
DS
0ns min.
0ns min. 0ns min.
5ns min. / 20ns max.
MOTOROLA BUS READ AC TIMING (BTS = 1 / MUX = 0) Figure 16.12
t1
t2 t3 t4
t5
75ns max.
DS21FT40
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MOTOROLA BUS WRITE AC TIMING (BTS=1 / MUX=0) Figure 17-7
Address ValidA0 to A7
D0 to D7
R/W*
CS*
DS*
0ns min.
0ns min.
75ns min.
0ns min.
10ns
min. 10ns
min.
t1
t2 t6 t4
t7 t8
RECEIVE SIDE AC TIMING Figure 17-8
tD1
1
tD2
RSER
RSYNC
Notes:
1. RSYNC is in the output mode (RCR1.5 = 0).
RCLK
tD2
RMSYNC
MSB of
Channel 1
DS21FT40
84 of 87
RECEIVE SYSTEM SIDE AC TIMI NG Figure 17-9
tF
t
R
tD3
1
tD4
t
tSU
HD
2
RSER / RSIG
RSYNC
RSYNC
Notes:
1. RSYNC is in the output mode (RCR1.5 = 0)
2. RSYNC is in the input mode (RCR1.5 = 1)
RSYSCLK
SL
t
tSP
SH
t
tD4
RMSYNC
MSB of
Channel 1
RECEIVE LINE I NTERFACE AC TIM ING Figure 17-10
tF
t
R
RPOS, RNEG
RCLK
CL
t
tCP
CH
t
tSU
tHD
DS21FT40
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TRANSMIT SIDE AC TIMI NG Figure 17-11
tF
t
R
1
TCLK
TSER
t
t
CL
tCH
CP
TSYNC
TSYNC
tD2
t
tSU HD
tHD
2
Notes:
1. TSYNC is in the output mode (TCR1.0 = 1).
2. TSYNC is in the input mode (TCR1.0 = 0).
3. TSER is sampled on the falling edge of TCLK when the transmit side elastic store is disabled.
tSU
TRANSMIT SYSTEM SIDE AC TIMI NG Figure 17-12
tF
t
R
TSYSCLK
TSER
t
t
SL
tSH
SP
TSSYNC
t
t
tSU HD
SU
Notes:
1. TSER is only sampled on the falling edge of TSYSCLK when the transmit side elastic store is enabled.
TRANSMIT LINE INTERFACE SIDE AC TIMING Figure 17-13
tF
t
R
TCLK
TPOS, TNEG
t
t
CL
tCH
CP
tDD
DS21FT40
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18. DS21FT40 MECHANICAL DIMENSIO NS
DS21FT40
87 of 87
POWER SUPPLY DE-COUPLING
In a typical PCB layout for the MCM, all of the VDD pins will connect to a common power plane and all
the VSS lines will connect to a common ground plane. The recommended method for de-coupling is
shown below in both schematic and pictorial form. As shown in the pictorial, the capacitors should be
symmetrically located about the device. Figure 18-1 uses standard capacitors, two .47 uf ceramics and
two .01uf ceramics. Since VDD and VSS signals will typically pass vertically to the power and ground
planes of a PCB, the de-coupling caps must be placed as close to the DS21FT40 as possible and routed
vertically to power and ground planes.
De-coupling scheme using standard tantalum caps. Figure 18-1