1
2002 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
MARCH 2002
CMOS SyncBiFIFOTM WITH
BUS-MATCHING AND BYTE SWAPPING
64 x 36 x 2
IDT723614
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. SyncBIFIFO is a trademark of Integrated Device Technology, Inc.
DSC-3146/1
FEATURES:
••
••
•Free-running CLKA and CLKB can be asynchronous or
coincident (simultaneous reading and writing of data on a
single clock edge is permitted)
••
••
•Two independent clocked FIFOs (64 x 36 storage capacity each)
buffering data in opposite directions
••
••
•Mailbox bypass Register for each FIFO
••
••
•Dynamic Port B bus sizing of 36 bits (long word), 18 bits (word),
and 9 bits (byte)
••
••
•Selection of Big- or Little-Endian format for word and byte bus
sizes
••
••
•Three modes of byte-order swapping on port B
••
••
•Programmable Almost-Full and Almost-Empty flags
••
••
•Microprocessor interface control logic
••
••
•EFA, FFA, AEA, and AFA flags synchronized by CLKA
••
••
•EFB, FFB, AEB, and AFB flags synchronized by CLKB
••
••
•Passive parity checking on each port
••
••
•Parity generation can be selected for each port
••
••
•Supports clock frequencies up to 67 MHz
••
••
•Fast access times of 10 ns
••
••
•Available in 132-pin plastic quad flat package (PQF) or space-
saving 120-pin thin quad flat package (TQFP)
••
••
•Industrial temperature range (–40 °°
°°
°C to +85°°
°°
°C) is available
FUNCTIONAL BLOCK DIAGRAM
Mail 1
Register
Input
Register
Output
Register
CLKA
CSA
W/RA
ENA
MBA
Port-A
Control
Logic
Device
Control
RST
CLKB
CSB
W/RB
ENB
Port-B
Control
Logic
MBF1
3146 drw01
Mail 2
Register
Write
Pointer Read
Pointer
Status Flag
Logic
Parity
Gen/Check
A
0
- A
35
36
RAM
ARRAY
64 x 36
Parity
Generation
Parity
Gen/Check
Programmable Flag
Offset Register
Status Flag
Logic
Input
Register
Output
Register
RAM
ARRAY
64 x 36
Parity
Generation
Read
Pointer
PEFB
PGB
EFB
AEB
FFB
AFB
ODD/
EVEN
FFA
AFA
FS0
FS1
EFA
AEA
PGA
PEFA
MBF2
Write
Pointer
FIFO2
FIFO1
36
36
BE
SIZ0
SIZ1
SW0
SW1
Bus Matching &
Byte Swapping
B
0
-B
35
Byte Matching &
Byte Swapping
2
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
DESCRIPTION:
The IDT723614 is a monolithic, high-speed, low-power CMOS bidirectional
clocked FIFO memory. It supports clock frequencies up to 67MHz and has read
access times as fast as 10ns. Two independent 64 x 36 dual-port SRAM FIFOs
on board the chip buffer data in opposite directions. Each FIFO has flags to
indicate empty and full conditions and two programmable flags (Almost-Full and
Almost-Empty) to indicate when a selected number of words is stored in memory.
FIFO data on port B can be input and output in 36-bit, 18-bit, and 9-bit formats
PIN CONFIGURATIONS
with a choice of big- or little-endian configurations. Three modes of byte-order
swapping are possible with any bus size selection. Communication between
each port can bypass the FIFOs via two 36-bit mailbox registers. Each mailbox
register has a flag to signal when new mail has been stored. Parity is checked
passively on each port and may be ignored if not desired. Parity generation
can be selected for data read from each port. Two or more devices can be used
in parallel to create wider data paths.
NOTES:
1. NC - No internal connection.
2. Uses Yamaichi socket IC51-1324-828.
GND
AEB
EFB
B
0
B
1
B
2
GND
B
3
B
4
B
5
B
6
V
CC
B
7
B
8
B
9
GND
B
10
B
11
V
CC
B
12
B
13
B
14
GND
B
15
B
16
B
17
B
18
B
19
B
20
GND
B
21
B
22
B
23
GND
AEA
EFA
A
0
A
1
A
2
GND
A
3
A
4
A
5
A
6
V
CC
A
7
A
8
A
9
GND
A
10
A
11
V
CC
A
12
A
13
A
14
GND
A
15
A
16
A
17
A
18
A
19
A
20
GND
A
21
A
22
A
23
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
116
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
3146 drw02
117
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
V
CC
V
CC
A
24
A
25
A
26
A
27
GND
A
28
A
29
V
CC
A
30
A
31
A
32
GND
A
33
A
34
A
35
GND
B
35
B
34
B
33
GND
B
32
B
31
B
30
V
CC
B
29
B
28
B
27
GND
B
26
B
25
B
24
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83 AFB
AFA
FFA
CSA
ENA
CLKA
W/RA
V
CC
PGA
FS
0
ODD/EVEN
FS
1
PEFA
MBF2
RST
BE
GND
SW1
SW0
SIZ1
MBF1
GND
PEFB
V
CC
W/RB
CLKB
ENB
CSB
FFB
GND
MBA
SIZ0
PGB
*
*Electrical pin 1 in center of beveled edge. Pin 1 identifier in corner.
PQFP (PQ132-1, ORDER CODE: PQF)
TOP VIEW
3
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
TQFP (PN120-1, ORDER CODE: PF)
TOP VIEW
PIN CONFIGURATIONS (CONTINUED)
This device is a clocked FIFO, which means each port employs a synchro-
nous interface. All data transfers through a port are gated to the LOW-to-HIGH
transition of a continuous (free-running) port clock by enable signals. The clocks
for each port are independent of one another and can be asynchronous or
coincident. The enables for each port are arranged to provide a simple
bidirectional interface between microprocessors and/or buses controlled by a
synchronous interface.
B
22
B
21
GND
B
20
B
19
B
18
B
17
B
16
B
15
B
14
B
13
B
12
B
11
B
10
GND
B
9
B
8
B
7
V
CC
B
6
B
5
B
4
B
3
GND
B
2
B
1
B
0
EFB
AEB
AFB
A
23
A
22
A
21
GND
A
20
A
19
A
18
A
17
A
16
A
15
A
14
A
13
A
12
A
11
A
10
GND
A
9
A
8
A
7
V
CC
A
6
A
5
A
4
A
3
GND
A
2
A
1
A
0
EFA
AEA
3146 drw03
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
91
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
AFA
FFA
CSA
ENA
CLKA
W/RA
V
CC
PGA
PEFA
MBF
2
MBA
FS
1
FS
0
ODD/EVEN
RST
GND
BE
SW1
SW0
SIZ1
SIZ0
MBF
1
PEFB
PGB
V
CC
W/RB
CLKB
ENB
CSB
FFB
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60 B
23
A
24
A
25
A
26
V
CC
A
27
A
28
A
29
GND
A
30
A
31
A
34
A
35
B
35
GND
B
34
B
33
B
32
B
30
B
31
GND
B
29
B
28
B
27
V
CC
B
26
B
25
B
24
A
32
A
33
The Full Flag (FFA, FFB) and Almost-Full flag (AFA, AFB) of a FIFO are
two-stage synchronized to the port clock that writes data to its array. The Empty
Flag (EFA, EFB) and Almost-Empty (AEA, AEB) flag of a FIFO are two stage
synchronized to the port clock that reads data from its array.
The IDT723614 is characterized for operation from 0°C to 70°C.
4
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
Symbol Name I/O Description
A0-A35 Port A Data I/O 36-bit bidirectional data port for side A.
AEA Port A Almost-Empty O Programmable Almost-Empty flag synchronized to CLKA. It is LOW when the number of 36-bit
Flag (Port A) words in FIFO2 is less than or equal to the value in the offset register, X.
AEB Port B Almost-Empty O
Programmable Almost-Empty flag synchronized to CLKB. It is LOW when
the number of 36-bit
Flag (Port B) words in FIFO1 is less than or equal to the value in the offset register, X.
AFA Port A Almost-Full O Programmable Almost-Full flag synchronized to CLKA. It is LOW when the number of 36-bit empty
Flag (Port A) locations in FIFO1 is less than or equal to the value in the offset register, X.
AFB Port B Almost-Full O Programmable Almost-Full flag synchronized to CLKB. It is LOW when the number of 36-bit empty
Flag (Port B) locations in FIFO2 is less than or equal to the value in the offset register, X.
B0-B35 Port B Data I/O 36-bit bidirectional data port for side B.
BE Big-endian select I Selects the bytes on port B used during byte or word data transfer. A LOW on BE selects the most
most significant bytes on B0-B35 for use, and a HIGH selects the least significant bytes.
CLKA Port A Clock I
CLKA is a continuous clock that synchronizes all data transfers through port
A and can be
asynchronous or coincident to CLKB. EFA, FFA, AFA, and AEA are synchronized to the
LOW-to-HIGH transition of CLKA.
CLKB Port B Clock I
CLKB is a continuous clock that synchronizes all data transfers through port
B and can be
asynchronous or coincident to CLKA. Port B byte swapping and data port sizing operations are
also synchronous to the LOW-to-HIGH transi
tion of CLKB. EFB, FFB, AFB, and AEB are synchro-
nized to the LOW-to-
HIGH transition of CLKB.
CSA Port A Chip Select I CSA must be LOW to enable a LOW-to-HIGH transition of CLKA to read or write data on port A.
The A0-A35 outputs are in the high-impedance state when CSA is HIGH.
CSB Port B Chip Select I CSB must be LOW to enable a LOW-to-HIGH transition of CLKB to read or write data on port B.
The B0-B35 outputs are in the high-impedance state when CSB is HIGH.
EFA Port A Empty Flag O EFA is synchronized to the LOW-to-HIGH transition of CLKA. When EFA is LOW, FIFO2 is
(Port A) empty, and reads from its memory are disabled. Data can be read from FIFO2 to the output
register when EFA is HIGH. EFA is forced LOW when the device is reset and is set HIGH by
the second LOW-to-HIGH transition of CLKA after data is loaded into empty FIFO2 memory.
EFB Port B Empty Flag O EFB is synchronized to the LOW-to-HIGH transition of CLKB. When EFB is LOW, the FIFO1 is
(Port B) empty, and reads from its memory are disabled. Data can be read from FIFO1 to the output
register when EFB is HIGH. EFB is forced LOW when the device is reset and is set HIGH by the
second LOW-to-HIGH transition of CLKB after data is loaded into empty FIFO1 memory.
ENA Port A Enable I ENA must be HIGH to enable a LOW-to-HIGH transition of CLKA to read or write data on port A.
ENB Port B Enable I ENB must be HIGH to enable a LOW-to-HIGH transition of CLKB to read or write data on port B.
FFA Port A Full Flag O FFA is synchronized to the LOW-to-HIGH transition of CLKA. When FFA is
LOW, FIFO1
is full,
(Port A)
and writes to its memory are disabled. FFA is forced
LOW when the device is reset and is set
HIGH by the second LOW-to-HIGH transition of CLKA after reset.
FFB Port B Full Flag O FFB is synchronized to the LOW-to-HIGH transition of CLKB. When FFB is
LOW, FIFO2 is full,
(Port B)
and writes to its memory are disabled. FFB is forced
LOW when the device is reset and is set
HIGH by the second LOW-to-HIGH transition of CLKB after reset.
FS1, FS0 Flag-Offset Selects I The LOW-to-HIGH transition of RST latches the values of FS0 and FS1, which
selects one of
four preset values for the Almost-Full flag and Almost-Empty
flag offset.
MBA Port A Mailbox I A HIGH level on MBA chooses a mailbox register for a port A read or write operation. When the
Select A0-A35 outputs are active, a HIGH level on MBA selects data from the mail2 register foroutput,
and a LOW level selects FIFO2 output register data for output.
MBF1 Mail1 Register Flag O MBF1 is set LOW by a LOW-to-HIGH transition of CLKA that writes data to the
mail1 register.
Writes to the mail1 register are inhibited while MBF1 is set
LOW. MBF1 is set HIGH by aLOW-to-
HIGH transition of CLKB when a port B read is
selected and both SIZ1 and SIZ0 are HIGH.
MBF1 is set HIGH when the
device is reset.
MBF2 Mail2 Register Flag O MBF2 is set LOW by a LOW-to-HIGH transition of CLKB that writes data to the
mail2 register.
Writes to the mail2 register are inhibited while MBF2 is set
LOW. MBF2 is set HIGH by a LOW-to-
HIGH transition of CLKA when a port A read is selected and MBA is HIGH. MBF2 is set HIGH
when the device is reset.
PIN DESCRIPTION
5
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
PIN DESCRIPTION (CONTINUED)
Symbol Name I/O Description
ODD/ Odd/Even Parity I
Odd parity is checked on each port when ODD/EVEN is HIGH, and even parity
is checked when
EVEN Select ODD/EVEN is LOW. ODD/EVEN also selects the type of parity generated for each port if parity
generation is enabled for a read operation.
PEFA Port A Parity Error O
When any byte applied to terminals A0-A35 fails parity, PEFA is LOW. Bytes
are organized as
Flag (Port A) A0-A8, A9-A17, A18-A26, and A27-A35, with the most significant bit of each byte serving as the
parity bit. The type of parity checked is determined by the state of the ODD/EVEN input.
The parity trees used to check the A0-A35 inputs are s
hared by the mail2 register to generate
parity if parity generation is selected by PGA. Therefore, if a mail2 read parity generation is setup
by having W/RA LOW, MBA HIGH, and PGA HIGH, the PEFA flag is forced HIGH regardless of the
A0-A35 inputs.
PEFB Port B Parity Error O
When any valid byte applied to terminals B0-B35 fails parity, PEFB is LOW.
Bytes
are organized
Flag (Port B)
as B0-B8, B9-B17, B18-B26, B27-B35 with the most significant
bit of each byte serving as the parity
bit. A byte is valid when it is used by the bus
size selected for Port B. The type of parity checked is
determined by the state of the ODD/EVEN input.
The parity trees used to check the B0-B35 inputs are shared by the mail 1 register to generate parity if
parity generation is selected by PGB. Therefore, if a mail1
read
with parity generation is setup by
having W/RB LOW, SIZ1 and SIZ0 HIGH,
and PGB HIGH, the PEFB flag is forced HIGH regardless
of the state of the B0-B35 inputs.
P GA Port A Parity I Parity is generated for data reads from port A when PGA is HIGH. The type of parity generated is
Generation selected by the state of the ODD/EVEN input. Bytes are organized as A0-A8, A9-A17, A18-A26,
and A27-A35. The generated parity bits are output in the most significant bit of each byte.
P GB Port B Parity I Parity is generated for data reads from port B when PGB is HIGH. The type of parity generated is
Generation selected by the state of the ODD/EVEN input. Bytes are organized as B0-B8, B9-B17, B18-B26,
and B27-B35. The generated parity bits are output in the most significant bit of each byte.
RST Reset I To reset the device, four LOW-to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of
CLKB must occur while RST is LOW. This sets the AFA, AFB, MBF1, and MBF2 flags HIGH and
the EFA, EFB, AEA, AEB, FFA, and FFB flags LOW. The LOW-to-HIGH transition of RST latches
the status of the FS1 and FS0 inputs to select Almost-Full and Almost-Empty flag offsets.
SIZ0, SIZ1 Port B Bus Size I
A LOW-to-HIGH transition of CLKB latches the states of SIZ0, SIZ1, and BE,
and the following
Selects (Port B)
LOW-to-HIGH transition of CLKB implements the latched states as a port B bus size. Port B bus sizes
can be long word, word, or byte. A high on both SIZ0 and SIZ1 accesses the mailbox registers for
a port B 36-bit write or read.
SW0, SW1 Port B byte Swap I
At the beginning of each long word transfer, one of four modes of byte-order swapping is selected by
Select (Port B)
SW0 and SW1. The four modes are no swap, byte swap, word swap, and byte-word swap. Byte-
order swapping is possible with any bus-size selection.
W/RA Port A Write/Read I A HIGH selects a write operation and a LOW selects a read operation on for a LOW-to-HIGH port A
Select transition of CLKA. The A0-A35 outputs are in the high-impedance state when W/RA is HIGH.
W/RB Port B Write/Read I A HIGH selects a write operation and a LOW selects a read operation on for a LOW-to-HIGH port B
Select B transition of CLKB. The B0-B35 outputs are in the high-impedance state when W/RB is HIGH.
6
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE
RANGE (UNLESS OTHERWISE NOTED)(1)
Symbol Rating Commercial Unit
VCC Supply Voltage Range –0.5 to 7 V
VI(2) Input Voltage Range –0.5 to VCC+0.5 V
VO(2) Output Voltage Range –0.5 to VCC+0.5 V
IIK Input Clamp Current, (VI < 0 or VI > VCC) ±20 mA
IOK Output Clamp Current, (VO < 0 or VO > VCC) ±50 mA
IOUT Continuous Output Current, (VO = 0 to VCC) ±50 mA
ICC Continuous Current Through VCC or GND ±500 mA
TSTG Storage Temperature Range –65 to 150 °C
NOTES:
1. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device
at these or any other conditions beyond those indicated under "Recommended Operating Conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended
periods may affect device reliability.
2. The input and output voltage ratings may be exceeded provided the input and output current ratings are observed.
Symbol Parameter Min. Max. Unit
VCC Supply Voltage 4.5 5.5 V
VIH HIGH Level Input Voltage 2 – V
VIL LOW-Level Input Voltage – 0.8 V
IOH HIGH-Level Output Current – – 4 mA
IOL LOW-Level Output Current – 8 mA
TAOperating Free-air Temperature 0 70 °C
RECOMMENDED OPERATING
CONDITIONS
ELECTRICAL CHARACTERISTICS OVER RECOMMENDED OPERATING
FREE-AIR TEMPERATURE RANGE (UNLESS OTHERWISE NOTED)
Parameter Test Conditions Min. Typ.(1) Max. Unit
VOH VCC = 4.5V, IOH = –4 mA 2.4 V
VOL VCC = 4.5 V, IOL = 8 mA 0.5 V
IIVCC = 5.5 V, VI = VCC or 0 ±50 µA
IOZ VCC = 5.5 V, VO = VCC or 0 ±50 µA
ICC(2) VCC = 5.5 V, IO = 0 mA, VI = VCC or GND 1 mA
CIN VI = 0, f = 1 MHz 4 pF
COUT VO = 0, f = 1 MHZ 8 pF
NOTES:
1 . All typical values are at VCC = 5 V, TA = 25°C.
2. For additional ICC information, see the following page.
7
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
CALCULATING POWER DISSIPATION
The ICC(f) current for the graph in Figure 1 was taken while simultaneously reading and writing the FIFO on the IDT723614 with CLKA and CLKB set
to fS. All data inputs and data outputs change state during each clock cycle to consume the highest supply current. Data outputs were disconnected to
normalize the graph to a zero-capacitance load. Once the capacitive lead per data-output channel is known, the power dissipation can be calculated with
the equation below.
With ICC(f) taken from Figure 1, the maximum power dissipation (PT) of the IDT723614 can be calculated by:
PT = VCC x ICC(f) + Σ(CL x VOH2 x fo)
where:
CL= output capacitance load
fo= switching frequency of an output
VOH = output high level voltage
When no reads or writes are occurring on the IDT723614, the power dissipated by a single clock (CLKA or CLKB) input running at frequency fs is
calculated by: PT=VCC x fS x 0.290 mA/MHz
010 20 30 40 50 60 70
0
50
100
150
200
250
300
350
400
fs Clock Frequency MHz
I CC(f) Supply Current mA
V
CC
= 5.5V
3146 drw04
80
V
CC
= 5V
V
CC
= 4.5V
fdata = 1/2 fs
T
A
= 25° C
C
L
= 0 pF
Figure 1. Typical Characteristics: Supply Current vs Clock Frequency
8
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
DC ELECTRICAL CHARACTERISTICS OVER RECOMMENDED RANGES OF
SUPPLY VOLTAGE AND OPERATING FREE-AIR TEMPERATURE
Commercial Com'l & Ind'l(1)
IDT723614L15 IDT723614L20
Symbol Parameter Min. Max. Min. Max. Unit
fSClock Frequency, CLKA or CLKB – 66.7 – 50 M Hz
tCLK Clock Cycle Time, CLKA or CLKB 15 – 20 – n s
tCLKH Pulse Duration, CLKA and CLKB HIGH 6 – 8 – n s
tCLKL Pulse Duration, CLKA and CLKB LOW 6 – 8 – ns
tDS Setup Time, A0-A35 before CLKA↑ and B0-B35 before CLKB↑4–5–ns
tENS Setup Time, CSA, W/RA, ENA and MBA before CLKA↑; CSB, W/RB and ENB 5 – 5 – n s
before CLKB↑
tSZS Setup Time, SIZ0, SIZ1, and BE before CLKB↑4–5–ns
tSWS Setup Time, SW0 and SW1 before CLKB↑5–7–ns
tPGS Setup Time, ODD/EVEN and PGA before CLKA↑; ODD/EVEN and PGB before 4 – 5 – ns
CLKB↑(2)
tRSTS Setup Time, RST LOW before CLKA↑ or CLKB↑(3) 5–6–ns
tFSS Setup Time, FS0 and FS1 before RST HIGH 5 – 6 – n s
tDH Hold Time, A0-A35 after CLKA↑ and B0-B35 after CLKB↑1–1–ns
tENH Hold Time, CSA, W/RA, ENA and MBA after CLKA↑; CSB, W/RB, and ENB 1 – 1 – n s
after CLKB↑
tSZH Hold Time, SIZ0, SIZ1, and BE after CLKB↑2–2–ns
tSWH Hold Time, SW0 and SW1 after CLKB↑0–0–ns
tPGH Hold Time, ODD/EVEN and PGA after CLKA↑; ODD/EVEN and PGB after 0 – 0 – ns
CLKB↑(2)
tRSTH Hold Time, RST LOW after CLKA↑ or CLKB↑(3) 5–6–ns
tFSH Hold Time, FS0 and FS1 after RST HIGH 4 – 4 – n s
tSKEW1(4) Skew Time, between CLKA↑ and CLKB↑ for EFA, EFB, FFA, and FFB 8–8–ns
tSKEW2(4) Skew Time, between CLKA↑ and CLKB↑ for AEA, AEB, AFA, and AFB 14 – 16 – ns
NOTES:
1. Industrial temperature range product for 20ns speed grade is available as a standard device. All other speed grades are available by special order.
2. Only applies for a clock edge that does a FIFO read.
3. Requirement to count the clock edge as one of at least four needed to reset a FIFO.
4. Skew time is not a timing constraint for proper device operation and is only included to illustrate the timing relationship between CLKA cycle and CLKB cycle.
(Commercial: VCC = 5.0V ±10%, T A = 0°C to +70°C; Industrial; VCC = 5.0V ± 10%,TA = 40°C to +85°C)
9
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
Commercial Com'l & Ind'l(1)
IDT723614L15 IDT723614L20
Symbol Parameter Min. Max. Min. Max. Unit
tAAccess Time, CLKA↑ to A0-A35 and CLKB↑ to B0-B35 2 10 2 12 ns
tWFF Propagation Delay Time, CLKA↑ to FFA and CLKB↑ to FFB 210212ns
tREF Propagation Delay Time, CLKA↑ to EFA and CLKB↑ to EFB 210212ns
tPAE Propagation Delay Time, CLKA↑ to AEA and CLKB↑ to AEB 210212ns
tPAF Propagation Delay Time, CLKA↑ to AFA and CLKB↑ to AFB 210212ns
tPMF Propagation Delay Time, CLKA↑ to MBF1 LOW or MBF2 HIGH and CLKB↑ to 1 9 1 12 ns
MBF2 LOW or MBF1 HIGH
tPMR Propagation Delay Time, CLKA↑ to B0-B35(2) and CLKB↑ to A0-A35(3) 311313ns
tPPE(4) Propagation delay time, CLKB↑ to PEFB 211212ns
tMDV Propagation Delay Time, MBA to A0-A35 valid and SIZ1, SIZ0 to B0-B35 valid 1 1 1 1 11. 5 n s
tPDPE Propagation Delay Time, A0-A35 valid to PEFA valid; B0-B35 valid to PEFB valid 3 10 3 11 ns
tPOPE Propagation Delay Time, ODD/EVEN to PEFA and PEFB 311312ns
tPOPB(5) Propagation Delay Time, ODD/EVEN to parity bits (A8, A17, A26, A35) and 2 11 2 12 ns
(B8, B17, B26, B35)
tPEPE Propagation Delay Time, CSA, ENA, W/RA, MBA, or PGA to PEFA; CSB, ENB, 1 11 1 12 n s
W/RB, SIZ1, SIZ0, or PGB to PEFB
tPEPB(5) Propagation Delay Time, CSA, ENA, W/RA, MBA, or PGA to parity bits (A8, A17, 3 12 3 13 ns
A26, A35); CSB, ENB, W/RB, SIZ1, SIZ0, or PGB to parity bits (B8, B17, B26, B35)
tRSF Propagation Delay Time, RST to (MBF1, MBF2) HIGH 1 15 1 20 n s
tEN Enable Time, CSA and W/RA LOW to A0-A35 active and CSB LOW and W/RB210212ns
HIGH to B0-B35 active
tDIS Disable Time, CSA or W/RA HIGH to A0-A35 at high-impedance and CSB HIGH or 1 8 1 9 n s
W/RB LOW to B0-B35 at high-impedance
SWITCHING CHARACTERISTICS OVER RECOMMENDED RANGES OF
SUPPLY VOLTAGE AND OPERATING FREE-AIR TEMPERATURE, CL = 30PF
NOTES:
1. Industrial temperature range product for 20ns speed grade is available as a standard device. All other speed grades are available by special order.
2. Writing data to the mail1 register when the B0-B35 outputs are active and SIZ1, SIZ0 are HIGH.
3. Writing data to the mail2 register when the A0-A35 outputs are active and MBA is HIGH.
4. Only applies when a new port B bus size is implemented by the rising CLKB edge.
5. Only applies when reading data from a mail register.
(Commercial: VCC = 5.0V ±10%, T A = 0°C to +70°C; Industrial; VCC = 5.0V ± 10%,TA = 40°C to +85°C)
10
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
B, EFB is set LOW when the fourth byte or second word of the last long word
is read.
The read pointer of a FIFO is incremented each time a new word is
clocked to the output register. The state machine that controls an Empty
Flag monitors a write-pointer and read-pointer comparator that indicates
when the FIFO SRAM status is empty, empty+1, or empty+2. A word written
to a FIFO can be read to the FIFO output register in a minimum of three
cycles of the Empty Flag synchronizing clock. Therefore, an Empty Flag is
LOW if a word in memory is the next data to be sent to the FIFO output
register and two cycles of the port clock that reads data from the FIFO have
not elapsed since the time the word was written. The Empty Flag of the FIFO
is set HIGH by the second LOW-to-HIGH transition of the synchronizing
clock, and the new data word can be read to the FIFO output register in the
following cycle.
A LOW-to-HIGH transition on an Empty Flag synchronizing clock begins
the first synchronization cycle of a write if the clock transition occurs at time tSKEW1
or greater after the write. Otherwise, the subsequent clock cycle can be the first
synchronization cycle (see Figure 14 and 15).
FULL FLAG (FFA, FFB)
The Full Flag of a FIFO is synchronized to the port clock that writes data
to its array. When the Full Flag is HIGH, a memory location is free in the
SRAM to receive new data. No memory locations are free when the full flag
is LOW and attempted writes to the FIFO are ignored.
Each time a word is written to a FIFO, the write pointer is incremented.
The state machine that controls a Full Flag monitors a write-pointer and
read-pointer comparator that indicates when the FIFO SRAM status is full,
full-1, or full-2. From the time a word is read from a FIFO, the previous
memory location is ready to be written in a minimum of three cycles of the
Full Flag synchronizing clock. Therefore, a Full Flag is LOW if less than two
cycles of the Full Flag synchronizing clock have elapsed since the next
memory write location has been read. The second LOW-to-HIGH transition
on the Full Flag synchronization clock after the read sets the Full Flag HIGH and
the data can be written in the following clock cycle.
A LOW-to-HIGH transition on a Full Flag synchronizing clock begins the
first synchronization cycle of a read if the clock transition occurs at time
tSKEW1 or greater after the read. Otherwise, the subsequent clock cycle can
be the first synchronization cycle (see Figure 16 and 17).
ALMOST-EMPTY FLAGS (AEA, AEB)
The Almost-Empty flag of a FIFO is synchronized to the port clock that
reads data from its array. The state machine that controls an Almost-Empty
flag monitors a write-pointer and a read-pointer comparator that indicates
when the FIFO SRAM status is almost-empty, almost-empty+1, or almost-
empty+2. The almost-empty state is defined by the value of the Almost-Full
and Almost-Empty Offset register (X). This register is loaded with one of
four preset values during a device reset (see Reset above). An Almost-
Empty flag is LOW when the FIFO contains X or less long words in memory
and is HIGH when the FIFO contains (X+1) or more long words.
Two LOW-to-HIGH transitions of the Almost-Empty flag synchronizing
clock are required after a FIFO write for the Almost-Empty flag to reflect the
new level of fill. Therefore, the Almost-Empty flag of a FIFO containing
(X+1) or more long words remains LOW if two cycles of the synchronizing
clock have not elapsed since the write that filled the memory to the (X+1)
level. An Almost-Empty flag is set HIGH by the second LOW-to-HIGH
transition of the synchronizing clock after the FIFO write that fills memory
to the (X+1) level. A LOW-to-HIGH transition of an Almost-Empty flag
synchronizing clock begins the first synchronization cycle if it occurs at time
SIGNAL DESCRIPTIONS
RESET
The IDT723614 is reset by taking the Reset (RST) input LOW for at least
four port A clock (CLKA) and four port B clock (CLKB) LOW-to-HIGH
transitions. The Reset input can switch asynchronously to the clocks. A
device reset initializes the internal read and write pointers of each FIFO and
forces the Full Flags (FFA, FFB) LOW, the Empty Flags (EFA, EFB) LOW,
the Almost-Empty flags (AEA, AEB) LOW and the Almost-Full flags (AFA,
AFB) HIGH. A reset also forces the Mailbox Flags (MBF1, MBF2) HIGH.
After a reset, FFA is set HIGH after two LOW-to-HIGH transitions of CLKA
and FFB is set HIGH after two LOW-to-HIGH transitions of CLKB. The
device must be reset after power up before data is written to its memory.
A LOW-to-HIGH transition on the RST input loads the Almost-Full and
Almost-Empty Offset register (X) with the values selected by the Flag Select
(FS0, FS1) inputs. The values that can be loaded into the registers are
shown in Table 1.
FIFO WRITE/READ OPERATION
The state of port A data A0-A35 outputs is controlled by the port A Chip
Select (CSA) and the port A Write/Read select (W/RA). The A0-A35 outputs
are in the high-impedance state when either CSA or W/RA is HIGH. The A0-
A35 outputs are active when both CSA and W/RA are LOW. Data is loaded
into FIFO1 from the A0-A35 inputs on a LOW-to-HIGH transition of CLKA
when CSA is LOW, W/RA is HIGH, ENA is HIGH, MBA is LOW, and FFA
is HIGH. Data is read from FIFO2 to the A0-A35 outputs by a LOW-to-HIGH
transition of CLKA when CSA is LOW, W/RA is LOW, ENA is HIGH, MBA
is LOW, and EFA is HIGH (see Table 2).
The port B control signals are identical to those of port A. The state of the
port B data (B0-B35) outputs is controlled by the port B Chip Select (CSB)
and the port B Write/Read select (W/RB). The B0-B35 outputs are in the high-
impedance state when either CSB or W/RB is HIGH. The B0-B35 outputs are
active when both CSB and W/RB are LOW. Data is loaded into FIFO2 from the
B0-B35 inputs on a LOW-to-HIGH transition of CLKB when CSB is LOW, W/RB
is HIGH, ENB is HIGH, EFB is HIGH, and either SIZ0 or SIZ1 is LOW. Data
is read from FIFO1 to the B0-B35 outputs by a LOW-to-HIGH transition of CLKB
when CSB is LOW, W/RB is LOW, ENB is HIGH, EFB is HIGH, and either SIZ0
or SIZ1 is LOW (see Table 3).
The setup and hold time constraints to the port clocks for the port Chip
Selects (CSA, CSB) and Write/Read selects (W/RA, W/RB) are only for
enabling write and read operations and are not related to high-impedance
control of the data outputs. If a port enable is LOW during a clock cycle, the
port Chip Select and Write/Read select can change states during the setup
and hold time window of the cycle.
SYNCHRONIZED FIFO FLAGS
Each FIFO is synchronized to its port clock through two flip-flop stages.
This is done to improve flag reliability by reducing the probability of
metastable events on the output when CLKA and CLKB operate asynchro-
nously to one another. EFA, AEA, FFA, and AFA are synchronized to CLKA.
EFB, AEB, FFB, and AFB are synchronized to CLKB. Tables 4 and 5 show
the relationship of each port flag to FIFO1 and FIFO2.
EMPTY FLAGS (EFA, EFB)
The Empty Flag of a FIFO is synchronized to the port clock that reads data
from its array. When the Empty Flag is HIGH, new data can be read to the FIFO
output register. When the Empty Flag is LOW, the FIFO is empty and attempted
FIFO reads are ignored. When reading FIFO1 with a byte or word size on port
11
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
tSKEW2 or greater after the write that fills the FIFO to (X+1) long words.
Otherwise, the subsequent synchronizing clock cycle can be the first
synchronization cycle (see Figure 18 and 19).
ALMOST FULL FLAGS (AFA, AFB)
The Almost-Full flag of a FIFO is synchronized to the port clock that writes
data to its array. The state machine that controls an Almost-Full flag
monitors a write-pointer and read-pointer comparator that indicates when
the FIFO SRAM status is almost full, almost full-1, or almost full-2. The
almost-full state is defined by the value of the Almost-Full and Almost-Empty
Offset register (X). This register is loaded with one of four preset values
during a device reset (see Reset above). An Almost-Full flag is LOW when
the FIFO contains (64-X) or more long words in memory and is HIGH when
the FIFO contains [64-(X+1)] or less long words.
Two LOW-to-HIGH transitions of the Almost-Full flag synchronizing clock
are required after a FIFO read for the Almost-Full flag to reflect the new level
of fill. Therefore, the Almost-Full flag of a FIFO containing [64-(X+1)] or less
words remains LOW if two cycles of the synchronizing clock have not
elapsed since the read that reduced the number of long words in memory
to [64-(X+1)]. An Almost-Full flag is set HIGH by the second LOW-to-HIGH
transition of the synchronizing clock after the FIFO read that reduces the
number of long words in memory to [64-(X+1)]. A LOW-to-HIGH transition
of an Almost-Full flag synchronizing clock begins the first synchronization
cycle if it occurs at time tSKEW2 or greater after the read that reduces the number
of long words in memory to [64-(X+1)]. Otherwise, the subsequent synchro-
nizing clock cycle can be the first synchronization cycle (see Figure 20 and 21).
MAILBOX REGISTERS
Each FIFO has a 36-bit bypass register to pass command and control
information between port A and port B without putting it in queue. The
Mailbox-Select (MBA, MBB) inputs choose between a mail register and a
FIFO for a port data transfer operation. A LOW-to-HIGH transition on CLKA
writes A0-A35 data to the mail1 register when a port A write is selected by
CSA, W/RA, and ENA with MBA HIGH. A LOW-to-HIGH transition on CLKB
writes B0-B35 data to the mail2 register when a port B write is selected by
CSB, W/RB, and ENB with both SIZ1 and SIZ0 HIGH. Writing data to a mail
register sets the corresponding flag (MBF1 or MBF2) LOW. Attempted
writes to a mail register are ignored while the mail flag is LOW.
When the port A data outputs (A0-A35) are active, the data on the bus
comes from the FIFO2 output register when MBA is LOW and from the mail2
register when MBA is HIGH. When the port B data outputs (B0-B35) are
active, the data on the bus comes from the FIFO1 output register when
either one or both SIZ1 and SIZ0 are LOW and from the mail2 register when
both SIZ1 and SIZ0 are HIGH. The Mail1 Register Flag (MBF1) is set HIGH
CSB W/RB ENB SIZ1, SIZ0 CLKB B0-B35 Outputs Port Functions
H X X X X In High-Impedance State None
L H L X X In High-Impedance State None
L H H One, both LOW ↑In High-Impedance State FIFO2 Write
L H H Both HIGH ↑In High-Impedance State Mail2 Write
L L L One, both LOW X Active, FIFO1 Output Register None
L L H One, both LOW ↑Active, FIFO1 Output Register FIFO1 read
L L L Both HIGH X Active, Mail1 Register None
L L H Both HIGH ↑Active, Mail1 Register Mail1 Read (Set MBF1 HIGH)
TABLE 3 PORT-B ENABLE FUNCTION TABLE
CSA W/RA ENA MBA CLKA A0-A35 Outputs Port Functions
H X X X X In High-Impedance State None
L H L X X In High-Impedance State None
LHHL↑In High-Impedance State FIFO1 Write
LHHH↑In High-Impedance State Mail1 Write
L L L L X Active, FIFO2 Output Register None
LLHL↑Active, FIFO2 Output Register FIFO2 Read
L L L H X Active, Mail2 Register None
LLHH↑Active, Mail2 Register Mail2 Read (Set MBF2 HIGH)
TABLE 2 PORT-A ENABLE FUNCTION TABLE
ALMOST-FULL AND
FS1 FS0 RST ALMOST-EMPTY FLAG
OFFSET REGISTER (X)
HH↑16
HL↑12
LH↑8
LL↑4
TABLE 1 FLAG PROGRAMMING
12
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
DYNAMIC BUS SIZING
The port B bus can be configured in a 36-bit long word, 18-bit word, or 9-
bit byte format for data read from FIFO1 or written to FIFO2. Word- and byte-
size bus selections can utilize the most significant bytes of the bus (Big-
Endian) or least significant bytes of the bus (Little-Endian). Port B bus size
can be changed dynamically and synchronous to CLKB to communicate
with peripherals of various bus widths.
The levels applied to the port B bus Size select (SIZ0, SIZ1) inputs and
the Big-Endian select (BE) input are stored on each CLKB LOW-to-HIGH
transition. The stored port B bus size selection is implemented by the next
rising edge on CLKB according to Figure 2.
Only 36-bit long-word data is written to or read from the two FIFO
memories on the IDT723614. Bus-matching operations are done after data
is read from the FIFO1 RAM and before data is written to the FIFO2 RAM.
Port B bus sizing does not apply to mail register operations.
BUS-MATCHING FIFO1 READS
Data is read from the FIFO1 RAM in 36-bit long word increments. If a long
word bus size is implemented, the entire long word immediately shifts to the
FIFO1 output register. If byte or word size is implemented on port B, only
the first one or two bytes appear on the selected portion of the FIFO1 output
register, with the rest of the long word stored in auxiliary registers. In this case,
subsequent FIFO1 reads with the same bus-size implementation output the rest
of the long word to the FIFO1 output register in the order shown by Figure 2.
Each FIFO1 read with a new bus-size implementation automatically unloads
data from the FIFO1 RAM to its output register and auxiliary registers. Therefore,
implementing a new port B bus size and performing a FIFO1 read before all bytes
or words stored in the auxiliary registers have been read results in a loss of the
unread long word data.
When reading data from FIFO1 in byte or word format, the unused B0-
B35 outputs remain inactive but static, with the unused FIFO1 output
register bits holding the last data value to decrease power consumption.
BUS-MATCHING FIFO2 WRITES
Data is written to the FIFO2 RAM in 36-bit long word increments. FIFO2
writes, with a long-word bus size, immediately store each long word in
FIFO2 RAM. Data written to FIFO2 with a byte or word bus size stores the
initial bytes or words in auxiliary registers. The CLKB rising edge that writes
the fourth byte or the second word of long word to FIFO2 also stores the
entire long word in FIFO2 RAM. The bytes are arranged in the manner
shown in Figure 2.
Each FIFO2 write with a new bus-size implementation resets the state
machine that controls the data flow from the auxiliary registers to the FIFO2
RAM. Therefore, implementing a new bus size and performing a FIFO2
write before bytes or words stored in the auxiliary registers have been
loaded to FIFO2 RAM results in a loss of data.
PORT-B MAIL REGISTER ACCESS
In addition to selecting port-B bus sizes for FIFO reads and writes, the
port B bus Size select (SIZ0, SIZ1) inputs also access the mail registers.
When both SIZ0 and SIZ1 are HIGH, the mail1 register is accessed for a port
B long word read and the mail2 register is accessed for a port B long word
write. The mail register is accessed immediately and any bus-sizing
operation that may be underway is unaffected by the mail register access.
After the mail register access is complete, the previous FIFO access can
resume in the next CLKB cycle. The logic diagram in Figure 3 shows the
previous bus-size selection is preserved when the mail registers are
accessed from port B. A port B bus size is implemented on each rising CLKB
edge according to the states of SIZ0_Q, SIZ1_Q, and BE_Q.
BYTE SWAPPING
The byte-order arrangement of data read from FIFO1 or data written to
FIFO2 can be changed synchronous to the rising edge of CLKB. Byte-order
swapping is not available for mail register data. Four modes of byte-order
swapping (including no swap) can be done with any data port size selection.
The order of the bytes are rearranged within the long word, but the bit order
within the bytes remains constant.
Byte arrangement is chosen by the port B Swap select (SW0, SW1)
inputs on a CLKB rising edge that reads a new long word from FIFO1 or
writes a new long word to FIFO2. The byte order chosen on the first byte or
first word of a new long word read from FIFO1 or written to FIFO2 is
maintained until the entire long word is transferred, regardless of the SW0
and SW1 states during subsequent writes or reads. Figure 4 is an example
of the byte-order swapping available for long words. Performing a byte swap
and bus size simultaneously for a FIFO1 read first rearranges the bytes as
shown in Figure 4, then outputs the bytes as shown in Figure 2. Simulta-
neous bus-sizing and byte-swapping operations for FIFO2 writes, first loads
the data according to Figure 2, then swaps the bytes as shown in Figure 4 when
the long word is loaded to FIFO2 RAM.
by a rising CLKB edge when a port B read is selected by CSB, W/RB, and ENB
with both SIZ1 and SIZ0 HIGH. The Mail2 Register Flag (MBF2) is set HIGH
by a LOW-to-HIGH transition on CLKA when port A read is selected by CSA,
W/RA, and ENA and MBA is HIGH. The data in the mail register remains intact
after it is read and changes only when new data is written to the register.
Synchronized Synchronized
Number of 36-Bit to CLKB to CLKA
Words in the FIFO1(1)
EFB AEB AFA FFA
0LLHH
1 to X H L H H
(X+1) to [64-(X+1)] H H H H
(64-X) to 63 H H L H
64 H H L L
TABLE 4 FIFO1 FLAG OPERATION
Synchronized Synchronized
Number of 36-Bit to CLKA to CLKB
Words in the FIFO2(1)
EFA AEA AFB FFB
0LLHH
1 to X H L H H
(X+1) to [64-(X+1)] H H H H
(64-X) to 63 H H L H
64 H H L L
TABLE 5 FIFO2 FLAG OPERATION
NOTE:
1. X is the value in the Almost-Empty flag and Almost-Full flag Offset register.
13
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
Figure 2. Dynamic Bus Sizing
B8B0
A
A
B
B
C
C
(a) LONG WORD SIZE
(b) WORD SIZE
BIG-ENDIAN
(c) WORD SIZE
LITTLE-ENDIAN
(d) BYTE SIZE
BIG-ENDIAN
Write to FIFO1/
Read From FIFO2
Read from FIFO1/
Write to FIFO2
1st: Read from FIFO1/
Write to FIFO2
2nd: Read from FIFO1/
Write to FIFO2
1st: Read from FIFO1/
Write to FIFO2
2nd: Read from FIFO1/
Write to FIFO2
1st: Read from FIFO1/
Write to FIFO2
2nd: Read from FIFO1/
Write to FIFO2
3rd: Read from FIFO1/
Write to FIFO2
4th: Read from FIFO1/
Write to FIFO2
BE SIZ1 SIZ0
BE SIZ1 SIZ0
BE SIZ1 SIZ0
BE SIZ1 SIZ0
L L H
H L H
L H L
X L L
BYTE ORDER ON PORT A:
3146 fig 01
B8B0
B8B0
B8B0
B8B0
B8B0
B8B0
B8B0
B8B0
D
D
ABCD
C D
AB
A
B
C
D
A35A27 A26A18 A17A9 A8A0
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
D
C
B8B0
(d) BYTE SIZE
LITTLE-ENDIAN
1st: Read from FIFO1/
Write to FIFO2
2nd: Read from FIFO1/
Write to FIFO2
A
B
3rd: Read from FIFO1/
Write to FIFO2
4th: Read from FIFO1/
Write to FIFO2
BE SIZ1 SIZ0
H H L
B8B0
B8B0
B8B0
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
B35B27 B26B18 B17B9
14
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
PARITY CHECKING
The port A inputs (A0-A35) and port B inputs (B0-B35) each have four
parity trees to check the parity of incoming (or outgoing) data. A parity failure
on one or more bytes of the port A data bus is reported by a LOW level on
the port Parity Error Flag (PEFA). A parity failure on one or more bytes of
the port B data input that are valid for the bus-size implementation is
reported by a LOW level on the port B Parity Error Flag (PEFB). Odd or Even
parity checking can be selected, and the Parity Error Flags can be ignored
if this feature is not desired.
Parity status is checked on each input bus according to the level of the
Odd/Even parity (ODD/EVEN) select input. A parity error on one or more
valid bytes of a port is reported by a LOW level on the corresponding port
Parity Error Flag (PEFA, PEFB) output. Port A bytes are arranged as A0-
A8, A9-A17, A18-A26, and A27-A35. Port B bytes are arranged as B0-B8,
B9-B17, B18-B26, and B27-B35, and its valid bytes are those used in a port
B bus-size implementation. When Odd/Even parity is selected, a port Parity
Error Flag (PEFA, PEFB) is LOW if any byte on the port has an odd/even
number of LOW levels applied to the bits.
The four parity trees used to check the A0-A35 inputs are shared by the mail2
register when parity generation is selected for port A reads (PGA = HIGH).
When a port A read from the mail2 register with parity generation is selected with
CSA LOW, ENA HIGH, W/RA LOW, MBA HIGH, and PGA HIGH, the port A
Parity Error Flag (PEFA) is held HIGH regardless of the levels applied to the
A0-A35 inputs. Likewise, the parity trees used to check the B0-B35 inputs are
shared by the mail1 register when parity generation is selected for port B reads
(PGB = HIGH). When a port B read from the mail1 register with parity generation
is selected with CSB LOW, ENB HIGH, W/RB LOW, both SIZ0 and SIZ1 HIGH,
and PGB HIGH, the port B Parity Error Flag (PEFB) is held HIGH regardless
of the levels applied to the B0-B35 inputs.
PARITY GENERATION
A HIGH level on the port A Parity Generate select (PGA) or port B Parity
Generate select (PGB) enables the IDT723614 to generate parity bits for port
reads from a FIFO or mailbox register. Port A bytes are arranged as A0-A8,
A9-A17, A18-26, and A27-A35, with the most significant bit of each byte used
as the parity bit. Port B bytes are arranged as B0-B8, B9-B17, B18-B26, and
B27-B35, with the most significant bit of each byte used as the parity bit. A write
to a FIFO or mail register stores the levels applied to all nine inputs of a byte
regardless of the state of the Parity Generate select (PGA, PGB) inputs. When
data is read from a port with parity generation selected, the lower eight bits of
each byte are used to generate a parity bit according to the level on the ODD/
EVEN select. The generated parity bits are substituted for the levels originally
written to the most significant bits of each byte as the word is read to the data
outputs.
Parity bits for FIFO data are generated after the data is read from SRAM
and before the data is written to the output register. Therefore, the port A
Parity Generate select (PGA) and Odd/Even parity select (ODD/EVEN) have
setup and hold time constraints to the port A Clock (CLKA) and the port B Parity
Generate select (PGB) and ODD/EVEN have setup and hold-time constraints
to the port B Clock (CLKB). These timing constraints only apply for a rising clock
edge used to read a new long word to the FIFO output register.
The circuit used to generate parity for the mail1 data is shared by the port B
bus (B0-B35) to check parity and the circuit used to generate parity for the mail2
data is shared by the port A bus (A0-A35) to check parity. The shared parity
trees of a port are used to generate parity bits for the data in a mail register when
the port Chip Select (CSA, CSB) is LOW, Enable (ENA, ENB) is HIGH, Write/
Read select (W/RA, W/RB) input is LOW, the Mail register is selected (MBA is
HIGH for port A; both SIZ0 and SIZ1 are HIGH for port B), and port Parity
Generate select (PGA, PGB) is HIGH. Generating parity for mail register data
does not change the contents of the register.
Figure 3. Logic Diagrams for SIZ0, SIZ1, and
BE
Register
MUX
G1
1
1
D Q SIZ0 Q
SIZ1 Q
BE Q
•
SIZ0
SIZ1
BE
CLKB
3146 fi
g
02
••
••
15
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
A
A
A
D
A
C
A
B
B
B
C
B
D
B
AB
C
C
C
B
C
A
C
D
D
D
D
A
D
B
D
C
B8B0
(a) NO SWAP
(b) BYTE SWAP
(c) WORD SWAP
(d) BYTE-WORD SWAP
L L
SW1 SW0
SW1 SW0
SW1 SW0
SW1 SW0
L L
L H
H L
H H
3146 fi
g
03
A8A0
B8B0
A8A0
A8A0
A8A0
B8B0
B8B0
A35A27 A26A18 A17A9
B35B27 B26B18 B17B9
A35A27 A26A18 A17A9
B35B27 B26B18 B17B9
A35A27 A26A18 A17A9
B35B27 B26B18 B17B9
A35A27 A26A18 A17A9
B35B27 B26B18 B17B9
Figure 4. Byte Swapping (Long Word Size Example)
16
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
Figure 5. Device Reset Loading the X Register with the Value of Eight
CLKA
RST
FFA
FFB
EFB
AEA
CLKB
EFA
FS1,FS0
3146 drw05
t
RSTS
t
RSTH
t
FSH
t
FSS
t
WFF
0,1
AFA
MBF1,
MBF2
t
WFF
AEB
AFB
t
WFF
t
REF
t
WFF
t
REF
t
RSF
t
PAE
t
PAF
t
PAE
t
PAF
17
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTE:
1. SIZ0 = HIGH and SIZ1 = HIGH writes data to the mail2 register
CLKB
ENB
SW1,
SW0
FFB
W/RB
B0-B35
BE
PEFB
ODD/
EVEN
HIGH
3146 drw 07
t
ENS
t
ENS
t
ENS
t
ENH
CSB
SIZ1,
SIZ0
VALID VALID
t
PDPE
NOT (1,1)
(1)
(0,0) t
DH
t
SZH
t
SZH
t
ENS
t
ENH
t
PPE
(0,0)
t
SWS
t
SWH
t
SZS
t
SZS
t
DS
DATA SWAP TABLE FOR LONG-WORD WRITES TO FIFO2
Figure 7. Port-B Long-Word Write Cycle Timing for FIFO2
3146 drw06
CLKA
FFA
ENA
A0 - A35
MBA
CSA
W/RA
t
ENS
t
ENS
t
ENS
t
ENS
t
DS
t
ENH
t
ENH
t
ENH
t
ENH
t
DH
W1
(1)
W2
(1)
t
ENS
t
ENH
t
ENH
t
ENS
No Operation
ODD/
EVEN
PEFA Valid Valid
t
PDPE
t
PDPE
HIGH
t
CLK
t
CLKH
t
CLKL
NOTE:
1. Written to FIFO1. Figure 6. Port-A Write Cycle Timing for FIFO1
SWAP MODE DATA WRITTEN TO FIFO2 DATA READ FROM FIFO2
SW1 SW0 B35-27 B26-18 B17-B9 B8-B0 A35-27 A26-A18 A17-A9 A8-A0
LLABCDABCD
LHDCBAABCD
HLCDABABCD
HHBADCABCD
18
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
CLKB
SW1, SW0
ENB
FFB
W/RB
BE
HIGH
3146 drw08
PEFB
ODD/EVEN
Big-
Endian B18-B35
Little-
Endian B0-B17
SIZ1, SIZ0
CSB
(0, 1) NOT (1,1)
(1)
t
ENH
t
ENH
t
ENH
t
SWH
t
SZH
t
SZH
t
SZH
t
SZS
t
SZS
t
SZS
t
SZS
t
DS
t
DS
VALID
VALID t
PDPE
t
DH
t
DH
t
SZH
t
SWS
(0, 1)
t
ENS
t
ENS
t
ENS
t
ENS
t
PPE
NOTES:
1. SIZ0 = HIGH and SIZ1 = HIGH writes data to the mail2 register.
2. PEFB indicates parity error for the following bytes: B35-B27 and B26-B18 for Big-Endian bus, and B17-B9 and B8-B0 for Little-Endian bus.
Figure 8. Port-B Word Write Cycle Timing for FIFO2
DATA SWAP TABLE FOR WORD WRITES TO FIFO2
DATA WRITTEN TO FIFO2
MODE NO. BIG-ENDIAN LITTLE-ENDIAN
SW1 SW0 B35-27 B26-18 B17-B9 B8-B0 A35-27 A26-A18 A17-A9 A8-A0
LL 1 A B C D A B C D
2C D A B
LH 1 D C B A A B C D
2B A D C
HL 1 C D A B A B C D
2A B C D
HH 1 B A D C A B C D
2D C B A
DATA READ FROM FIFO2
SWAP WRITE
19
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
FFB
CSB
W/RB
SIZ1,
SIZ0
CLKB
3146 drw09
HIGH
SW1,
SW0
BE
ODD/EVEN
B0-
B8
(1,0) (1,0) Not (1,1)
(1)
t
ENS
t
ENH
t
SWS
t
SZH
t
SZH
t
SZS
ENB
Little-
Endian
ValidValidValid
Valid
Big-
Endian B27-
B35
PEFB
t
PPE
t
PDPE
t
PDPE
t
PDPE
t
DS
t
DS
t
DH
t
DH
t
ENS
t
ENS
t
SZH
t
SZS
t
SZS
t
SZS
t
SZH
t
ENH
t
ENH
t
ENS
t
ENH
(1,0)
(1,0)
NOTES:
1. SIZ0 = HIGH and SIZ1 = HIGH writes data to the mail2 register.
2. PEFB indicates parity error for the following bytes: B35—B27 for Big-Endian bus and B17—B9 for Little-Endian bus.
DATA SWAP TABLE FOR BYTE WRITES TO FIFO2
Figure 9. Port-B Byte Write Cycle Timing for FIFO2
DATA READ FROM FIFO2
SWAP WRITE DATA WRITTEN TO FIFO2
MODE NO. BIG-ENDIAN LITTLE-ENDIAN
SW1 SW0 B35-27 B8-B0 A35-27 A26-A18 A17-A9 A8-A0
1A D
2B C
3C B
4D A
1D A
2C B
3B C
4A D
1C B
2D A
3A D
4B C
1B C
2A D
3D A
4C B
L L
L H
H L
H H
A B C D
A B C D
A B C D
A B C D
20
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTES:
1. SIZ0 = HIGH and SIZ1 = HIGH selects the mail1 register for output on B0-B35.
2. Data read from FIFO1.
CLKB
ENB
SW1,
SW0
EFB
W/RB
PGB,
BE
ODD/
EVEN
HIGH
3146 drw10
CSB
SIZ1,
SIZ0 NOT (1,1)
(1)
t
PGH
t
PGS
t
SZH
t
SZH
t
ENH
(0,0)
t
SWS
B0-B35
NOT (1,1)
(1)
Previous Data W 1
(2)
W2
(2)
t
DIS
t
ENS
t
ENH
t
SWH
t
ENS
No Operation
(0,0)
t
SZS
t
SZS
t
EN
t
A
t
A
DATA SWAP TABLE FOR FIFO LONG-WORD READS FROM FIFO1
Figure 10. Port-B Long-Word Read Cycle Timing for FIFO1
DATA WRITTEN TO FIFO1 SWAP MODE DATA READ FROM FIFO1
A35-27 A26-A18 A17-A9 A8-A0 SW1 SW0 B35-27 B26-18 B17-B9 B8-B0
AB C D L L A B C D
AB C D L H D C B A
AB C D H L C D A B
AB C D H H B A D C
21
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
CLKB
ENB
SW1,
SW0
EFB
W/RB
PGB,
BE
ODD/
EVEN
HIGH
3146 drw11
CSB
SIZ1,
SIZ0 NOT (1,1)
(1)
t
PGH
t
PGS
t
SZH
t
SZH
(0,1)
t
SWS
B0-B17
NOT (1,1)
(1)
Previous Data
t
ENS
t
ENH
t
SWH
No Operation
Previous DataB18-B35
Little-
Endian
Big-
Endian
Read 1
Read 1
Read 2
Read 2
(0,1)
(2)
(2)
t
SZS
t
SZS
t
EN
t
A
t
A
t
A
t
A
t
DIS
t
DIS
NOTES:
1. SIZ0 = HIGH and SIZ1 = HIGH selects the mail1 register for output on B0-B35.
2. Unused word B0-B17 or B18-B35 holds last FIFO1 output register data for word-size reads.
DATA SWAP TABLE FOR WORD READS FROM FIFO1
Figure 11. Port-B Word Read Cycle Timing for FIFO1
DATA WRITTEN TO FIFO1 SWAP MODE READ
NO. BIG-ENDIAN LITTLE-ENDIAN
A35-A27 A26-A18 A17-A9 A8-A0 S W 1 SW0 B35-B27 B26-B18 B17-B9 B8-B0
1A B CD
ABCD L L2CDAB
1D C BA
ABCD L H2BADC
1C D AB
ABCD H L2ABCD
1B A DC
ABCD H H2D CBA
DATA READ FROM FIFO1
22
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTES:
1. SIZ0 = HIGH and SIZ1 = HIGH selects the mail1 register for output on B0-B35.
2. Unused bytes hold last FIFO1 output register data for byte-size reads.
EFB
CSB
W/RB
SIZ1,
SIZ0
ENB
CLKB
3146 drw12
HIGH
SW1,
SW0
BE
PGB,
ODD/
EVEN
B0-B8
B27-B35 Read 4Read 1 Read 2
Read 4Read 1 Read 3
Read 3Previous Data
Previous Data Read 2
(1,0) (1,0) (1,0)
Not (1,1) (1)
No Operation
t
DIS
t
DIS
t
EN
t
PGH
t
PGS Not (1,1)(1)
Not (1,1) (1)
Not (1,1)(1)
(1,0)
t
ENH
t
SWH
t
SZH
t
SZH
t
SZS
t
SZS
t
ENS
t
SWS
t
A
t
A
t
A
t
A
t
A
t
A
t
A
t
A
DATA SWAP TABLE FOR BYTE READS FROM FIFO1
Figure 12. Port-B Byte Read Cycle Timing for FIFO1
1A D
2B C
ABC DLL3 C B
4D A
1D A
2C B
ABC DLH3 B C
4A D
1C B
2D A
ABC DHL3 A D
4B C
1B C
2A D
ABC DHH3 D A
4C B
DATA WRITTEN TO FIFO 1 SWAP MODE READ BIG- LITTLE-
NO. ENDIAN ENDIAN
A35-A27 A26-A18 A17-A9 A8-A0 SW1 SW0 B35-B27 B8-B0
DATA READ FROM FIFO 1
23
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
3146 drw13
CLKA
EFA
ENA
A0 - A35
MBA
CSA
W/RA
t
ENH
t
ENH
Previous Data Word 1 Word 2
(1) (1)
t
ENH
No Operation
PGA,
ODD/
EVEN
HIGH
t
PGH
t
PGH
t
CLK
t
CLKH
t
CLKL
t
ENS
t
A
t
PGS
t
A
t
PGS
t
ENS
t
ENS
t
DIS
t
EN
t
MDV
NOTE:
1. Read from FIFO2. Figure 13. Port-A Read Cycle Timing for FIFO2
NOTES:
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for EFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA
edge and rising CLKB edge is less than tSKEW1, then the transition of EFB HIGH may occur one CLKB cycle later than shown.
2. Port-B size of long word is selected for FIFO1 read by SIZ1 = LOW, SIZ0 = LOW. If port-B size is word or byte, EFB is set LOW by the last word or byte read from FIFO1,
respectively. Figure 14.
EFB
Flag Timing and First Data Read when FIFO1 is Empty
CSA
WRA
MBA
FFA
A0 - A35
CLKB
EFB
CSB
W/RB
SIZ1,
SIZ0
ENA
ENB
B0 -B35
CLKA
12
3146 drw14
t
ENS
t
ENS
t
ENH
t
ENH
t
DS
t
DH
t
ENS
t
ENH
W1
FIFO1 Empty
LOW
HIGH
LOW
LOW
LOW
W1
HIGH
t
CLK
t
CLKH
t
CLKL
t
SKEW1(1)
t
CLKH
t
CLK
t
CLKL
t
REF
t
REF
t
A
24
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
CSB
W/RB
SIZ1,
SIZ0
FFB
B0 - B35
CLKA
EFA
CSA
W/RA
MBA
ENB
ENA
A0 -A35
CLKB
12
3146 drw15
t
ENS
t
ENS
t
ENH
t
ENH
t
DS
t
DH
t
ENS
t
ENH
W1
FIFO2 Empty
LOW
HIGH
LOW
LOW
LOW
W1
HIGH
t
CLK
t
CLKH
t
SKEW1(1)
t
CLKH
t
CLK
t
REF
t
REF
t
A
t
CLKL
t
CLKL
NOTES:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for EFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB
edge and rising CLKA edge is less than tSKEW1, then the transition of EFA HIGH may occur one CLKA cycle later than shown.
2. Port B size of long word is selected for FIFO2 write by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte tSKEW1 is referenced to the rising CLKB edge that writes the
last word or byte of the long word, respectively.
Figure 15.
EFA
Flag Timing and First Data Read when FIFO2 is Empty
25
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
CSB
EFB
SIZ1,
SIZ0
ENB
B0 - B35
CLKB
FFA
CLKA
CSA
3146 drw16
WRA
12
A0 - A35
MBA
ENA
t
ENS
t
ENH
t
ENS
t
ENS
t
DS
t
ENH
t
ENH
t
DH
To FIFO1
Previous Word in FIFO1 Output Register Next Word From FIFO1
LOW
W/RBLOW
LOW
HIGH
LOW
HIGH
FIFO1 Full
t
CLK
t
CLKH
t
CLKL
t
A
t
SKEW1(1)
t
CLK
t
CLKH
t
CLKL
t
WFF
t
WFF
NOTES:
1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for FFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKB edge and
rising CLKA edge is less than tSKEW1, then FFA may transition HIGH one CLKA cycle later than shown.
2. Port B size of long word is selected for FIFO1 read by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte, tSKEW1 is referenced from the rising CLKB edge that reads the last
word or byte of the long word, respectively.
Figure 16.
FFA
Flag Timing and First Available Write when FIFO1 is Full.
26
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTES:
1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for FFB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA
edge and rising CLKB edge is less than tSKEW1, then FFB may transition HIGH one CLKB cycle later than shown.
2. Port B size of long word is selected for FIFO2 write by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte, FFB is set LOW by the last word or byte write of the long
word, respectively. Figure 17.
FFB
Flag Timing and First Available Write when FIFO2 is Full
NOTES:
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for AEB to transition HIGH in the next CLKB cycle. If the time between the rising CLKA
edge and rising CLKB edge is less than tSKEW2, then AEB may transition HIGH one CLKB cycle later than shown.
2 . FIFO1 Write (CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = LOW, MBB = LOW).
3. Port B size of long word is selected for FIFO1 read by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte, AEB is set LOW by the last word or byte read of the long
word, respectively. Figure 18. Timing for
AEB
when FIFO1 is Almost-Empty
CSA
EFA
MBA
ENA
A0 - A35
CLKA
FFB
CLKB
CSB
3146 drw17
W/RB
12
B0 - B35
SIZ1,
SIZ0
ENB
tENS tENH
tENS
tENS
tDS
tENH
tENH
tDH
To FIFO2
Previous Word in FIFO2 Output Register Next Word From FIFO2
LOW
W/RALOW
LOW
HIGH
LOW
HIGH
FIFO2 Full
tCLK
tCLKH tCLKL
tA
tSKEW1(1) tCLK
tCLKH tCLKL
tWFF tWFF
AEB
CLKA
ENB
3146 drw18
ENA
CLKB 2
1
t
ENS
t
ENH
t
ENS
t
ENH
X Long Word in FIFO1 (X+1) Long Words in FIFO1
t
SKEW2
(1)
t
PAE
t
PAE
27
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
AEA
CLKB
ENA
3146 drw19
ENB
CLKA 2
1
t
ENS
t
ENH
t
ENS
t
ENH
(X+1) Long Words in FIFO2
X Long Words in FIFO2
t
SKEW2(1)
t
PAE
t
PAE
NOTES:
1. tSKEW2 is the minimum time between a rising CLKB edge and a rising CLKA edge for AEA to transition HIGH in the next CLKA cycle. If the time between the rising
CLKB edge and rising CLKA edge is less than tSKEW2, then AEA may transition HIGH one CLKA cycle later than shown.
2 . FIFO2 Write (CSB = LOW, W/RB = HIGH, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW).
3. Port B size of long word is selected for FIFO2 write by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte, tSKEW2 is referenced from the rising CLKB edge that
writes the last word or byte of the long word, respectively.
Figure 19. Timing for
AEA
when FIFO2 is Almost-Empty
AFA
CLKA
ENB
3146 drw20
ENA
CLKB
12
t
ENS
t
ENH
t
ENS
t
ENH
[64-(X+1)] Long Words in FIFO1 (64-X) Long Words in FIFO1
t
SKEW2(1)
t
PAF
t
PAF
NOTES:
1. tSKEW2 is the minimum time between a rising CLKA edge and a rising CLKB edge for AFA to transition HIGH in the next CLKA cycle. If the time between the rising
CLKA edge and rising CLKB edge is less than tSKEW2, then AFA may transition HIGH one CLKB cycle later than shown.
2 . FIFO1 Write (CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO1 read (CSB = LOW, W/RB = LOW, MBB = LOW).
3. Port B size of long word is selected for FIFO1 read by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte, tSKEW2 is referenced from the last word or byte read of
the long word, respectively.
Figure 20. Timing for
AFA
when FIFO1 is Almost-Full
AFB
CLKB
ENA
3146 drw21
ENB
CLKA
12
t
ENS
t
ENH
t
ENS
t
ENH
[64-(X+1)] Long Words in FIFO2 (64-X) Long Words in FIFO2
t
SKEW2(1)
t
PAF
t
PAF
NOTES:
1. tSKEW2 is the minimum time between a rising CLKB edge and a rising CLKA edge for AFB to transition HIGH in the next CLKB cycle. If the time between the rising
CLKB edge and rising CLKA edge is less than tSKEW2, then AFB may transition HIGH one CLKA cycle later than shown.
2 . FIFO2 Write (CSB = LOW, W/RB = HIGH, MBB = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW).
3. Port B size of long word is selected for FIFO2 write by SIZ1 = LOW, SIZ0 = LOW. If port B size is word or byte, AFB is set LOW by the last word or byte read of
the long word, respectively. Figure 21. Timing for
AFB
when FIFO2 is Almost-Full
28
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTE:
1. Port B Parity Generation off (PGB = LOW).
Figure 22. Timing for Mail1 Register and
MBF1
Flag
3146 drw22
CLKA
ENA
A0 - A35
MBA
CSA
W/RA
CLKB
MBF1
CSB
SIZ1,
SIZ0
ENB
B0 - B35
W/RB
W1
tENS tENH
tDH
tEN
tENH
W1 (Remains valid in Mail1 Register after read)
FIFO1 Output Register
tDS
tPMF tPMF
tENS
tMDV tPMR tDIS
29
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTE:
1. Port-A Parity Generation off (PGA = LOW).
Figure 24. ODD/
EVEN
. W/
R
A, MBA, and PGA to
PEFA
Timing
Figure 23. Timing for Mail2 Register and
MBF2
Flag
3146 drw24
ODD/
EVEN
PEFA
PGA
MBA
W/RA
Valid Valid Valid Valid
t
POPE
t
PEPE
t
POPE
t
PEPE
3146 drw23
CLKB
ENB
B0 - B35
SIZ1,
SIZ0
CSB
W/RB
CLKA
MBF2
CSA
MBA
ENA
A0 - A35
W/RA
W1
tENH
tDH
tENH
tEN
FIFO2 Output Register W1 (Remains valid in Mail2 Register after read)
tSZH
tENS
tSZS
tDS
tPMF tPMF
tENS
tPMR
tMDV tDIS
30
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
3146 drw25
ODD/
EVEN
PEFB
PGB
SIZ1,
SIZ0
W/RB
Valid Valid Valid Valid
t
POPE
t
PEPE
t
POPE
t
PEPE
Figure 25. ODD/
EVEN
. W/
R
B, SIZ1, SIZ0, and PGB to
PEFB
Timing
Figure 27. Parity Generation Timing when Reading from the Mail1 Register
3146 drw27
ODD/
EVEN
B8, B17,
B26, B35
PGB
SIZ1,
SIZ0
W/RB
Mail1
Data
Generated Parity Generated Parity Mail1 Data
CSB LOW
t
EN
t
MDV
t
PEPB
t
POPB
t
PEPB
Figure 26. Parity Generation Timing when Reading from the Mail2 Register
3146 drw26
ODD/
EVEN
A8, A17,
A26, A35
PGA
MBA
W/RA
Mail2
Data
Generated Parity Generated Parity Mail2 Data
CSA LOW
t
EN
t
PEPB
t
MDV
t
POPB
t
PEPB
NOTE:
1. ENA is HIGH.
NOTE:
1. ENB is HIGH.
31
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723614 CMOS SYNCBIFIFO
WITH BUS-MATCHING
AND BYTE SWAPPING 64 x 36 x 2
NOTE:
1. Includes probe and jig capacitance.
Figure 28. Load Circuit and Voltage Waveforms
3146 drw28
From Output
Under Test
30 pF
1.1 kΩ
5 V
680Ω
LOAD CIRCUIT
3 V
GND
Timing
Input
Data,
Enable
Input
GND
3 V
1.5 V
1.5 V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES VOLTAGE WAVEFORMS
PULSE DURATIONS
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
3 V
GND
GND
3 V
1.5 V
1.5 V
1.5 V
1.5 V
Output
Enable
Low-Level
Output
High-Level
Output
3 V
VOL
GND
≈3 V
1.5 V 1.5 V
1.5 V
1.5 V VOH
≈OV
GND
VOH
VOL
1.5 V 1.5 V
1.5 V 1.5 V
Input
In-Phase
Output
High-Level
Input
Low-Level
Input
1.5 V
3 V
t
PLZ
t
PHZ
t
PZL
t
PZH
(1)
t
S
t
h
t
W
t
PD
t
PD
32
CORPORATE HEADQUARTERS for SALES: for TECH SUPPORT:
2975 Stender Way 800-345-7015 or 408-727-6116 e-mail: FIFOhelp@idt.com
Santa Clara, CA 95054 fax: 408-492-8674 Phone: (408) 330-1753
www.idt.com
NOTE:
1. Industrial temperature range product for 20ns speed grade is available as a standard device. All other speed grades are available by special order.
ORDERING INFORMATION
3146 drw29
IDT723614 64 x 36 x 2 SyncBiFIFO
723614IDT Device Type XXX X X
Power Speed Package
Clock Cycle Time (t
CLK
)
Speed in Nanoseconds
Process/
Temperature
Range
BLANK
I(1)
PF
PQF
15
20
L
Commercial (0°C to +70°C)
Industrial (40°C to +85°C)
Thin Quad Flat Pack (TQFP, PN120-1)
Plastic Quad Flat Pack (PQFP, PQ132-1)
Commercial Only
Com’l & Ind’l
Low Power
DATASHEET DOCUMENT HISTORY
03/05/2002 pgs. 1, 8, 9 and 32.
