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3.3 VOLT CMOS TRIPLE BUS SyncFIFOTM WITH BUS-MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
FEATURES:
*
PRELIMINARY IDT72V3656 IDT72V3666 IDT72V3676
* *
* *
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Memory storage capacity: IDT72V3656 - 2,048 x 36 x 2 IDT72V3666 - 4,096 x 36 x 2 IDT72V3676 - 8,192 x 36 x 2 Clock frequencies up to 100 MHz (6.5ns access time) Two independent FIFOs buffer data between one bidirectional 36-bit port and two unidirectional 18-bit ports (Port C receives and Port B transmits) 18-bit (word) and 9-bit (byte) bus sizing of 18 bits (word) on Ports B and C Select IDT Standard timing (using EFA , EFB , FFA , and FFC flag functions) or First Word Fall Through Timing (using ORA, ORB, IRA, and IRC flag functions) Programmable Almost-Empty and Almost-Full flags; each has five default offsets (8, 16, 64, 256 and 1,024)
* * * * * * *
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Serial or parallel programming of partial flags Big- or Little-Endian format for word and byte bus sizes Loopback mode on Port A Retransmit Capability Master Reset clears data and configures FIFO, Partial Reset clears data but retains configuration settings Mailbox bypass registers for each FIFO Free-running CLKA, CLKB and CLKC may be asynchronous or coincident (simultaneous reading and writing of data on a single clock edge is permitted) Auto power down minimizes power dissipation Available in a space-saving 128-pin Thin Quad Flatpack (TQFP) Pin and functionally compatible versions of the 5V parts, IDT723656/723666/723676 Pin compatible to the lower density parts, IDT72V3626/3636/3646 Industrial temperature range (-40C to +85C) is available
FUNCTIONAL BLOCK DIAGRAM
MBF1 CLKA CSA W/RA ENA MBA LOOP MRS1 PRS1 Mail 1 Register
Output BusMatching Output Register
Input Register
Port-A Control Logic
18
B0-B17
36
RAM ARRAY
2,048 x 36 4,096 x 36 8,192 x 36
36
FIFO1, Mail1 Reset Logic
36
Port-B Control Logic Write Pointer Read Pointer
CLKB RENB CSB MBB SIZEB
FFA/IRA AFA FS2 FS0/SD FS1/SEN A0-A35 EFA/ORA AEA
FIFO1
Status Flag Logic Common Port Control Logic (B and C)
EFB/ORB AEB
Programmable Flag Offset Registers
13 FIFO2
Timing Mode
BE
Status Flag Logic Read Pointer Write Pointer FIFO2, Mail2 Reset Logic
Input BusMatching Input Register
18
FWFT FFC/IRC AFC MRS2 PRS2
36
RT1 RTM RT2
Output Register
FIFO1 and FIFO2 Retransmit Logic
36
RAM ARRAY
2,048 x 36 4,096 x 36 8,192 x 36 Mail 2 Register
36
C0-C17 CLKC WENC MBC SIZEC
4665 drw01
Port-C Control Logic
MBF2
The SyncFIFO is a trademark and the IDT logo is a registered trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGE
MARCH 2001
1
DSC-4665/2
(c) 2001 Integrated Device Technology, Inc.
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
DESCRIPTION:
The IDT72V3656/72V3666/72V3676 are pin and functionally compatible versions of the IDT723626/723636/723646, designed to run off a 3.3V supply for exceptionally low-power consumption. These devices are a monolithic, high-speed, low-power, CMOS Triple Bus synchronous (clocked) FIFO memory which supports clock frequencies up to 100 MHz and has read access times as fast as 6.5ns. Two independent 2,048/4,096/8,192 x 36 dual-port
SRAM FIFOs on board each chip buffer data between a bidirectional 36-bit bus (Port A) and two unidirectional 18-bit buses (Port B transmits data, Port C receives data.) FIFO data can be read out of Port B and written into Port C using either 18-bit or 9-bit formats with a choice of Big- or Little-Endian configurations. These devices are a synchronous (clocked) FIFO, meaning each port employs a synchronous interface. All data transfers through a port are gated to the LOW-to-HIGH transition of a port clock by enable signals. The clocks for
PIN CONFIGURATION
CSA FFA/IRA EFA/ORA PRS1/RT1 VCC AFA AEA MBF2 MBA MRS1 FS0/SD CLKC GND FS1/SEN MRS2 MBB MBF1 VCC AEB AFC EFB/ORB FFC/IRC GND CSB WENC RENB
INDEX
39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
W/RA ENA CLKA GND A35 A34 A33 A32 Vcc A31 A30 GND A29 A28 A27 A26 A25 A24 A23 BE/FWFT GND A22 Vcc A21 A20 A19 A18 GND A17 A16 A15 A14 A13 Vcc A12 GND A11 A10
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 31 32 33 34 35 36 37 38
128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103
102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65
CLKB PRS2/RT2 LOOP C17 C16 C15 C14 RTM MBC C13 C12 C11 C10 C9 C8 VCC C7 C6 SIZEB GND C5 C4 C3 C2 C1 C0 GND B17 B16 SIZEC VCC B15 B14 B13 B12 GND B11 B10
A9 A8 A7 A6 GND A5 A4 A3 FS2 VCC A2 A1 A0 GND B0 B1 B2 B3 B4 B5 GND B6 VCC B7 B8 B9
4665 drw02
TQFP (PK128-1, order code: PF) TOP VIEW 2
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
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 with synchronous control. Communication between each port may bypass the FIFOs via two mailbox registers. The mailbox registers' width matches the selected bus width of ports B and C. Each mailbox register has a flag (MBF1 and MBF2) to signal when new mail has been stored. Two kinds of reset are available on these FIFOs: Master Reset and Partial Reset. Master Reset initializes the read and write pointers to the first location of the memory array and selects serial flag programming, parallel flag programming, or one of five possible default flag offset settings, 8, 16, 64, 256 or 1,024. Each FIFO has its own, independent Master Reset pin, MRS1 and MRS2. Partial Reset also sets the read and write pointers to the first location of the memory. Unlike Master Reset, any settings existing prior to Partial Reset (i.e., programming method and partial flag default offsets) are retained. Partial Reset is useful since it permits flushing of the FIFO memory without changing any configuration settings. Each FIFO has its own, independent Partial Reset pin, PRS1 and PRS2. Note that the Retransmit Mode, RTM pin must be LOW at the point a partial reset is performed. Both FIFO's have Retramsmit capability, when a Retransmit is performed on a respective FIFO only the read pointer is reset to the first memory location. A Retransmit is performed by using the Retransmit Mode, RTM pin in conjunction with the Retransmit pins RT1 or RT2, for each respective FIFO. Note that the two Retransmit pins RT1 and RT2 are muxed with the Partial Reset pins. These devices have two modes of operation: In the IDT Standard mode, the first word written to an empty FIFO is deposited into the memory array. A read operation is required to access that word (along with all other words residing in memory). In the First Word Fall Through mode (FWFT), the first word written to an empty FIFO appears automatically on the outputs, no read operation required (Nevertheless, accessing subsequent words does necessitate a formal read request). The state of the BE/FWFT pin during Master Reset determines the mode in use. Each FIFO has a combined Empty/Output Ready Flag (EFA/ORA and EFB/ORB) and a combined Full/Input Ready Flag (FFA/IRA and FFC/ IRC). The EF and FF functions are selected in the IDT Standard mode. EF indicates whether or not the FIFO memory is empty. FF shows whether the memory is full or not. The IR and OR functions are selected in the First Word Fall Through mode. IR indicates whether or not the FIFO has available memory locations. OR shows whether the FIFO has data available for reading or not. It marks the presence of valid data on the outputs. Each FIFO has a programmable Almost-Empty flag (AEA and AEB) and a programmable Almost-Full flag (AFA and AFC). AEA and AEB indicate when
a selected number of words remain in the FIFO memory. AFA and AFC indicate when the FIFO contains more than a selected number of words. FFA/IRA, FFC/IRC, AFA and AFC are two-stage synchronized to the Port Clock that writes data into its array. EFA/ORA, EFB/ORB, AEA, and AEB are two-stage synchronized to the Port Clock that reads data from its array. Programmable offsets for AEA, AEB, AFA, AFC are loaded in parallel using Port A or in serial via the SD input. Five default offset settings are also provided. The AEA and AEB threshold can be set at 8, 16, 64, 256, and 1,024 locations from the empty boundary and the AFA and AFC threshold can be set at 8, 16, 64, 256 or 1,024 locations from the full boundary. All these choices are made using the FS0, FS1 and FS2 inputs during Master Reset. Interspersed Parity can also be selected during a Master Reset of the FIFO. If Interspersed Parity is selected then during parallel programming of the flag offset values, the device will ignore data line A8. If Non-Interspersed Parity is selected then data line A8 will become a valid bit. A Loopback function is provided on Port A. When the Loop feature is selected via the LOOP pin, the data output from FIFO2 will be directed to the data input of FIFO1. If Loop is selected and Port A is set-up for write operation via W/RA pin, then data output from FIFO2 will be written to FIFO1, but will not be placed on the output Port A (A0-A35). If Port A is set-up for read operation via W/RA then data output from FIFO2 will be written into FIFO1 and placed onto Port A (A0-A35). The Loop will continue to happen provided that FIFO1 is not full and FIFO2 is not empty. If during a Loop sequence FIFO1 becomes full then any data that continues to be read out from FIFO2 will only be placed on the Port A (A0-A35) lines, provided that Port A is set-up for read operation. If during a Loop sequence the FIFO2 becomes empty, then the last word from FIFO2 will continue to be clocked into FIFO1 until FIFO1 becomes full or until the Loop function is stopped. The Loop feature can be useful when performing system debugging and remote loopbacks. Two or more FIFOs may be used in parallel to create wider data paths. Such a width expansion requires no additional, external components. Furthermore, two IDT72V3656/72V3666/72V3676 FIFOs can be combined with unidirectional FIFOs capable of First Word Fall Through timing (i.e. the SuperSync FIFO family) to form a depth expansion. If, at any time, the FIFO is not actively performing a function, the chip will automatically power down. During the power down state, supply current consumption (ICC) is at a minimum. Initiating any operation (by activating control inputs) will immediately take the device out of the power down state. The IDT72V3656/72V3666/72V3676 are characterized for operation from 0C to 70C. Industrial temperature range (-40C to +85C) is available by special order. They are fabricated using IDT's high speed, submicron CMOS technology.
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IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTIONS
Symbol A0-A35 AEA AEB AFA AFC B0-B17 BE/FWFT Name Port A Data Port A AlmostEmpty Flag Port B AlmostEmpty Flag Port A AlmostFull Flag Port C AlmostFull Flag Port B Data Big-Endian/ First Word Fall Through Select I/O I/O O O O O O I 36-bit bidirectional data port for side A. Programmable Almost-Empty flag synchronized to CLKA. It is LOW when the number of words in FIFO2 is less than or equal to the value in the Almost-Empty A Offset register, X2. Programmable Almost-Empty flag synchronized to CLKB. It is LOW when the number of words in FIFO1 is less than or equal to the value in the Almost-Empty B Offset register, X1. Programmable Almost-Full flag synchronized to CLKA. It is LOW when the number of empty locations in FIFO1 is less than or equal to the value in the Almost-Full A Offset register, Y1. Programmable Almost-Full flag synchronized to CLKC. It is LOW when the number of empty locations in FIFO2 is less than or equal to the value in the Almost-Full C Offset register, Y2. 18-bit output data port for side B. This is a dual purpose pin. During Master Reset, a HIGH on BE will select Big-Endian operation. In this case, depending on the bus size, the most significant byte or word on Port A is read from Port B first (A-to-B data flow) or is written to Port C first (C-to-A data flow). A LOW on BE will select Little-Endian operation. In this case, the least significant byte or word on Port A is read from Port B first (A-to-B data flow) or is written to Port C first (C-to-A data flow). After Master Reset, this pin selects the timing mode. A HIGH on FWFT selects IDT Standard mode, a LOW selects First Word Fall Through mode. Once the timing mode has been selected, the level on FWFT must be static throughout device operation. C0-C17 CLKA Port C Data Port A Clock I I 18-bit input data port for side C. CLKA is a continuous clock that synchronizes all data transfers through Port A and can be asynchronous or coincident to CLKB. FFA/IRA, EFA/ORA, AFA, and AEA are all synchronized to the LOW-to-HIGH transition of CLKA. CLKB is a continuous clock that synchronizes all data transfers through Port B and can be asynchronous or coincident to CLKA. EFB/ORB and AEB are synchronized to the LOW-to-HIGH transition of CLKB. CLKC is a continuous clock that synchronizes all data transfers through Port C and can be asynchronous or coincident to CLKA. FFC/IRC and AFC are synchronized to the LOW-to-HIGH transition of CLKC. CSA must be LOW to enable to LOW-to-HIGH transition of CLKA to read or write on Port A. The A0-A35 outputs are in the high-impedance state when CSA is HIGH. CSB must be LOW to enable a LOW-to-HIGH transition of CLKB to read data on Port B. The B0-B17 outputs are in the high-impedance state when CSB is HIGH. This is a dual function pin. In the IDT Standard mode, the EFA function is selected. EFA indicates whether or not the FIFO2 memory is empty. In the FWFT mode, the ORA function is selected. ORA indicates the presence of valid data on the A0-A35 outputs, available for reading. EFA/ORA is synchronized to the LOW-to-HIGH transition of CLKA. This is a dual function pin. In the IDT Standard mode, the EFB function is selected. EFB indicates whether or not the FIFO1 memory is empty. In the FWFT mode, the ORB function is selected. ORB indicates the presence of valid data on the B0-B17 outputs, available for reading. EFB/ORB is synchronized to the LOW-to-HIGH transition of CLKB. ENA must be HIGH to enable a LOW-to-HIGH transition of CLKA to read or write data on Port A. This is a dual function pin. In the IDT Standard mode, the FFA function is selected. FFA indicates whether or not the FIFO1 memory is full. In the FWFT mode, the IRA function is selected. IRA indicates whether or not there is space available for writing to the FIFO1 memory. FFA/IRA is synchronized to the LOW-to-HIGH transition of CLKA. This is a dual function pin. In the IDT Standard mode, the FFC function is selected. FFC indicates whether or not the FIFO2 memory is full. In the FWFT mode, the IRC function is selected. IRC indicates whether or not there is space available for writing to the FIFO2 memory. FFC/IRC is synchronized to the LOW-to-HIGH transition of CLKC. Description
CLKB CLKC CSA CSB EFA/ORA
Port B Clock Port C Clock Port A Chip Select Port B Chip Select Port A Empty/ Output Ready Flag Port B Empty/ Output Ready Flag
I I I I O
EFB/ORB
O
ENA FFA/IRA
Port A Enable Port A Full/ Input Ready Flag
I O
FFC/IRC
Port C Full/ Input Ready Flag
O
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IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTIONS (CONTINUED)
Symbol FS0/SD Name I/O Description Flag Offset Select 0/ I FS1/SEN and FS0/SD are dual-purpose inputs used for flag Offset register programming. During Master Reset, Serial Data FS1/SEN and FS0/SD, together with FS2, select the flag offset programming method. Three Offset register programming methods are available: automatically load one of five preset values (8, 16, 64, 256 or 1,024), Flag Offset Select 1/ I parallel load from Port A, and serial load. Serial Enable When serial load is selected for flag Offset register programming, FS1/SEN is used as an enable synchronous to Flag Offset Select 2 I the LOW-to-HIGH transition of CLKA. When FS1/SEN is LOW, a rising edge on CLKA load the bit present on FS0/SD into the X and Y registers. The number of bit writes required to program the Offset registers is 44 for the 72V3656, 48 for the 72V3666, and 52 for the 72V3676. The first bit write stores the Y-register (Y1) MSB and the last bit write stores the X-register (X2) LSB. Loopback Select I This pin selects the loopback feature for Port A. During Loopback data from FIFO2 will be directed to the input of FIFO1. to initiate a Loop the LOOP pin must be held LOW and the ENA pin must be HIGH. Port A Mailbox Select Port B Mailbox Select Port C Mailbox Select Mail1 Register Flag Mail2 Register Flag Master Reset I A HIGH level on MBA chooses a mailbox register for a Port A read or write operation. When the A0-A35 outputs are active, a HIGH level on MBA selects data from the mail2 register for output and a LOW level selects FIFO2 output-register data for output. A HIGH level on MBB chooses a mailbox register for a Port B read operation. When the B0-B17 outputs are active, a HIGH level on MBB selects data from the mail1 register for output and a LOW level selects FIFO1 output register data for output.
FS1/SEN
FS2(1)
LOOP MBA
MBB
I
MBC MBF1
A HIGH level on MBC chooses the mail2 register for a Port C write operation. This pin must be HIGH during Master Reset. 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 LOW. MBF1 is set HIGH by a LOW-to-HIGH transition of CLKB when a Port B read is selected and MBB is HIGH. MBF1 is set HIGH following either a Master or Partial Reset of FIFO1. O MBF2 is set LOW by a LOW-to-HIGH transition of CLKC that writes data to the mail2 register. Writes to the mail2 register are inhibited while MBF2 is 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 following either a Master or Partial Reset of FIFO2. I A LOW on this pin initializes the FIFO1 read and write pointers to the first location of memory and sets the Port B output register to all zeroes. A LOW-to-HIGH transition on MRS1 selects the programming method (serial or parallel) and one of five programmable flag default offsets for FIFO1 and FIFO2. It also configures ports B and C for bus size and endian arrangement. Four LOW-to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of CLKB must occur while MRS1 is LOW. I A LOW on this pin initializes the FIFO2 read and write pointers to the first location of memory and sets the Port A output register to all zeroes. A LOW-to-HIGH transition on MRS2, toggled simultaneously with MRS1, selects the programming method (serial or parallel) and one of the five flag default offsets for FIFO2. Four LOW-to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of CLKC must occur while MRS2 is LOW. I This pin is muxed for both Partial Reset and Retransmit operations, it is used in conjunction with the RTM pin. If RTM is in a LOW condition, a LOW on this pin performs a Partial Reset on FIFO1 and initializes the FIFO1 read and write pointers to the first location of memory and sets the Port B output register to all zeroes. During Partial Reset, the currently selected bus size, endian arrangement, programming method (serial or parallel), and programmable flag settings are all retained. If RTM is HIGH, a LOW on this pin performs a Retransmit and initializes the FIFO1 read pointer only to the first memory location. I This pin is muxed for both Partial Reset and Retransmit operations, it is used in conjunction with the RTM pin. If RTM is in a LOW condition, a LOW on this pin performs a Partial Reset on FIFO2 and initializes the FIFO2 read and write selected bus size, endian arrangement, programming method (serial or parallel), and programmable flag settings are all retained. If RTM is HIGH, a LOW on this pin performs a Retransmit and initializes the FIFO2 read pointer only to the first memory location. RENB must be HIGH to enable a LOW-to-HIGH transition of CLKB to read data on Port B. This pin is used in conjunction with the RT1 and RT2 pins. When RTM is HIGH a Retransmit is performed on FIFO1 or FIFO2 respectively.
I
MBF2
MRS1
MRS2
Master Reset
PRS1/ RT1
Partial Reset/ Retransmit FIFO1
PRS2/ RT2
Partial Reset/ Retransmit FIFO2
RENB RTM
Port B Read Enable I Retransmit Mode I
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IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTIONS (CONTINUED)
Symbol SIZEB
(1)
Name Port B Bus Size Select Port C Bus Size Select Port C Write Enable Port A Write/ Read Select
I/O I
Description SIZEB determines the bus width of Port B. A HIGH on this pin selects byte (9-bit) bus size. A LOW on this pin selects word (18-bit) bus size. SIZEB works with SIZEC and BE to select the bus size and endian arrangement for ports B and C. The level of SIZEB must be static throughout device operation. SIZEC determines the bus width of Port C. A HIGH on this pin selects byte (9-bit) bus size. A LOW on this pin selects word (18-bit) bus size. SIZEC works with SIZEB and BE to select the bus size and endian arrangement for ports B and C. The level of SIZEC must be static throughout device operation. WENC must be HIGH to enable a LOW-to-HIGH transition of CLKC to write data on Port C. A HIGH selects a write operation and a LOW selects a read operation on Port A for a LOW-to-HIGH transition of CLKA. The A0-A35 outputs are in the HIGH impedance state when W/RA is HIGH.
SIZEC(1)
I
WENC W/RA
I I
NOTE: 1. FS2, SIZEB and SIZEC inputs are not TTL compatible. These inputs should be tied to GND or VCC.
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IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE RANGE (Unless otherwise noted)(1)
Symbol VCC VI
(2) (2)
Rating Supply Voltage Range Input Voltage Range Output Voltage Range Input Clamp Current (VI < 0 or VI > VCC) Output Clamp Current (VO = < 0 or VO > VCC) Continuous Output Current (VO = 0 to VCC) Continuous Current Through VCC or GND Storage Temperature Range
Commercial -0.5 to +4.6 -0.5 to VCC+0.5 -0.5 to VCC+0.5 20 50 50 400 -65 to 150
Unit V V V mA mA mA mA C
VO
IIK IOK IOUT ICC TSTG
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.
RECOMMENDED OPERATING CONDITIONS
Symbol VCC VCC VIH VIL IOH IOL TA
(1)
Parameter Supply Voltage for 10ns Supply Voltage for 15ns High-Level Input Voltage Low-Level Input Voltage High-Level Output Current Low-Level Output Current Operating Temperature
Min. 3.15 3.0 2 -- -- -- 0
Typ. 3.3 3.3 -- -- -- -- --
Max. 3.45 3.6 VCC+0.5 0.8 -4 8 70
Unit V V V V mA mA
C
NOTE: 1. For 10ns speed grade: Vcc = 3.3V 0.15V, JEDEC JESD8-A compliant
ELECTRICAL CHARACTERISTICS OVER RECOMMENDED OPERATING FREE-AIR TEMPERATURE RANGE (Unless otherwise noted)
IDT72V3656 IDT72V3666 IDT72V3676 Commercial tCLK = 10, 15 ns(2) Min. Typ.(1) Max. 2.4 -- -- -- -- -- -- -- -- -- -- -- -- -- 4 8 -- 0.5 10 10 5 1 -- --
Symbol VOH VOL ILI ILO ICC2 CIN
(3)
Parameter Output Logic "1" Voltage Output Logic "0" Voltage Input Leakage Current (Any Input) Output Leakage Current Standby Current (with CLKA, CLKB & CLKC running) Standby Current (no clocks running) Input Capacitance Output Capacitance VCC = 3.0V, VCC = 3.0V, VCC = 3.6V, VCC = 3.6V, VCC = 3.6V, VCC = 3.6V, VI = 0, VO = 0,
Test Conditions IOH = -4 mA IOL = 8 mA VI = VCC or 0 VO = VCC or 0 VI = VCC -0.2V or 0V VI = VCC -0.2V or 0V f = 1 MHz f = 1 MHZ
Unit V V A A mA mA pF pF
ICC3(3)
(4)
COUT(4)
NOTES: 1. All typical values are at VCC = 3.3V, TA = 25C. 2. Commercial-10ns speed grade only: Vcc = 3.3V 0.15V, TA = 0 to +70; JEDEC JESD8-A compliant. 3. For additional ICC information, see Figure 1, Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS). 4. Characterized values, not currently tested.
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IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
DETERMINING ACTIVE CURRENT CONSUMPTION AND POWER DISSIPATION The ICC(f) current for the graph in Figure 1 was taken while simultaneously reading and writing a FIFO on the IDT72V3656/72V3666/72V3676 with CLKA, CLKB and CLKC 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 capacitance load per data-output channel and the number of these device's inputs driven by TTL HIGH levels are known, the power dissipation can be calculated with the equation below. CALCULATING POWER DISSIPATION With ICC(f) taken from Figure 1, the maximum power dissipation (PT) of these FIFOs may be calculated by: PT = VCC x ICC(f) + (CL x VCC2 x fo)
N
where: N = number of used outputs (36-bit (long word), 18-bit (word) or 9-bit (byte) bus size) CL = output capacitance load fo = switching frequency of an output
100
90
VCC = 3.6V
80
70
VCC = 3.0V
60
fdata = 1/2 fS TA = 25C CL = 0 pF
VCC = 3.3V
50
Supply Current ICC(f)
mA
40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100
4665 drw02a
fS Clock Frequency MHz
Figure 1. Typical Characteristics: Supply Current (ICC) vs. Clock Frequency (fS)
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IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
TIMING REQUIREMENTS OVER RECOMMENDED RANGES OF SUPPLY VOLTAGE AND OPERATING FREE-AIR TEMPERATURE
(For 10ns speed grade only: Vcc = 3.3V 0.15V; TA = 0C to +70C; JEDEC JESD8-A compliant) IDT72V3656L10(1) IDT72V3666L10(1) IDT72V3676L10(1) Min. Max. -- 10 4.5 4.5 3 4 3 5 7.5 7.5 3 3 0 5 0.5 0.5 4 2 2 0.5 0.5 2 5 5 100 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- IDT72V3656L15 IDT72V3666L15 IDT72V3676L15 Min. Max. -- 15 6 6 4 4.5 4.5 5 8.5 7.5 4 4 0 5 1 1 4 2 2 1 1 2 5 7.5 66.7 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Symbol fS tCLK tCLKH tCLKL tDS tENS1 tENS2 tRSTS tFSS tBES tSDS tSENS tFWS tRTMS tDH tENH tRSTH tFSH tBEH tSDH tSENH tSPH tRTMH tSKEW1
(3)
Parameter Clock Frequency, CLKA, CLKB, or CLKC Clock Cycle Time, CLKA, CLKB, or CLKC Pulse Duration, CLKA, CLKB, or CLKC HIGH Pulse Duration, CLKA, CLKB, OR CLKC LOW Setup Time, A0-A35 before CLKA and C0-C17 before CLKC Setup Time, CSA and W/RA before CLKA; CSB before CLKB Setup Time, ENA, and MBA before CLKA; RENB and MBB before CLKB; WENC and MBC before CLKC Setup Time, MRS1, MRS2, PRS1, PRS2, RT1 or RT2 LOW before CLKA or CLKB(2) Setup Time, FS0, FS1, FS2 before MRS1 and MRS2 HIGH Setup Time, BE/FWFT before MRS1 and MRS2 HIGH Setup Time, FS0/SD before CLKA Setup Time, FS1/SEN before CLKA Setup Time, BE/FWFT before CLKA Setup Time, RTM before RT1; RTM before RT2 Hold Time, A0-A35 after CLKA and C0-C17 after CLKC Hold Time, CSA, W/RA, ENA, and MBA after CLKA; CSB, RENB, and MBB after CLKB; WENC and MBC after CLKC Hold Time, MRS1, MRS2, PRS1, PRS2, RT1 or RT2 LOW after CLKAor CLKB(2) Hold Time, FS0, FS1, FS2 after MRS1 and MRS2 HIGH Hold Time, BE/FWFT after MRS1 and MRS2 HIGH Hold Time, FS0/SD after CLKA Hold Time, FS1/SEN HIGH after CLKA Hold Time, FS1/SEN HIGH after MRS1 and MRS2 HIGH Hold Time, RTM after RT1; RTM after RT2 Skew Time, between CLKA and CLKB for EFB/ORB and FFA/IRA; between CLKA and CLKC for EFA/ORA and FFC/IRC Skew Time, between CLKA and CLKB for AEB and AFA; between CLKA and CLKC for AEA and AFC
Unit MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
tSKEW2(3,4)
12
--
12
--
ns
NOTES: 1. For 10ns speed grade: Vcc = 3.3V 0.15V; TA = 0 to +70. 2. Requirement to count the clock edge as one of at least four needed to reset a FIFO. 3. Skew time is not a timing constraint for proper device operation and is only included to illustrate the timing relationship among CLKA cycle, CLKB cycle, and CLKC cycle. 4. Design simulated, not tested.
9
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
SWITCHING CHARACTERISTICS OVER RECOMMENDED RANGES OF SUPPLY VOLTAGE AND OPERATING FREE-AIR TEMPERATURE, CL = 30PF
(For 10ns speed grade only: Vcc = 3.3V 0.15V; TA = 0C to +70C; JEDEC JESD8-A compliant) IDT72V3656L10(1) IDT72V3666L10(1) IDT72V3676L10(1) Min. Max. 2 2 1 1 1 0 3 2 1 6.5 6.5 6.5 6.5 6.5 6.5 6.5 8 10 IDT72V3656L15 IDT72V3666L15 IDT72V3676L15 Min. Max. 2 2 1 1 1 0 2 2 1 10 8 8 8 8 8 10 10 15
Symbol tA tWFF tREF tPAE tPAF tPMF tPMR tMDV tRSF
Parameter Access Time, CLKA to A0-A35 and CLKB to B0-B17 Propagation Delay Time, CLKA to FFA/IRA and CLKC to FFC/IRC Propagation Delay Time, CLKA to EFA/ORA and CLKB to EFB/ORB Propagation Delay Time, CLKA to AEA and CLKB to AEB Propagation Delay Time, CLKA to AFA and CLKC to AFC Propagation Delay Time, CLKA to MBF1 LOW or MBF2 HIGH, CLKB to MBF1 HIGH, and CLKC to MBF2 LOW Propagation Delay Time, CLKA to B0-B17(2) and CLKC to A0-A35(3) Propagation Delay Time, MBA to A0-A35 valid and MBB to B0-B17 valid Propagation Delay Time, MRS1 or PRS1 LOW to AEB LOW, AFA HIGH, and MBF1 HIGH and MRS2 or PRS2 LOW to AEA LOW, AFC HIGH, and MBF2 HIGH Enable Time, CSA or W/RA LOW to A0-A35 Active and CSB LOW to B0-B17 Active Disable Time, CSA or W/RA HIGH to A0-A35 at high impedance and CSB HIGH to B0-B17 at HIGH impedance
Unit ns ns ns ns ns ns ns ns ns
tEN tDIS
2 1
6 6
2 1
10 8
ns ns
NOTES: 1. For 10ns speed grade: Vcc = 3.3V 0.15V; TA = 0 to +70. 2. Writing data to the mail1 register when the B0-B17 outputs are active and MBB is HIGH. 3. Writing data to the mail2 register when the A0-A35 outputs are active and MBA is HIGH.
10
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
SIGNAL DESCRIPTION
MASTER RESET (MRS1, MRS2) After power up, a Master Reset operation must be performed by providing a LOW pulse to MRS1 and MRS2 simultaneously. Afterwards, the FIFO1 memory of the IDT72V3656/72V3666/72V3676 undergoes a complete reset by taking its associated Master Reset (MRS1) input LOW for at least four Port A Clock (CLKA) and four Port B Clock (CLKB) LOW-to-HIGH transitions. The FIFO2 memory undergoes a complete reset by taking its associated Master Reset (MRS2) input LOW for at least four Port A Clock (CLKA) and four Port C Clock (CLKC) LOW-to-HIGH transitions. The Master Reset inputs can switch asynchronously to the clocks. A Master Reset initializes the associated read and write pointers to the first location of the memory and forces the Full/Input Ready flag (FFA/IRA, FFC/IRC) LOW, the Empty/Output Ready flag (EFA/ORA, EFB/ORB) LOW, the Almost-Empty flag (AEA, AEB) LOW and the AlmostFull flag (AFA, AFC) HIGH. A Master Reset also forces the associated Mailbox Flag (MBF1, MBF2) of the parallel mailbox register HIGH. After a Master Reset, the FIFO's Full/Input Ready flag is set HIGH after two Write Clock cycles. Then the FIFO is ready to be written to. A LOW-to-HIGH transition on the FIFO1 Master Reset (MRS1) input latches the value of the Big-Endian (BE) input for determining the order by which bytes are transferred through Ports B and C. It also latches the values of the Flag Select (FS0, FS1 and FS2) inputs for choosing the Almost-Full and AlmostEmpty offsets and programming method. A LOW-to-HIGH transition on the FIFO2 Master Reset (MRS2) clears the flag offset registers of FIFO2 (X2, Y2). A LOW-to-HIGH transition on the FIFO2 Master Reset (MRS2) together with the FIFO1 Master Reset input (MRS1) latches the value of the Big-Endian (BE) input for Ports B and C and also latches the values of the Flag Select (FS0, FS1 and FS2) inputs for choosing the AlmostFull and Almost-Empty offsets and programming method (for details see Table 1, Flag Programming, and Almost-Empty and Almost-Full flag offset programming section). The relevant Master Reset timing diagrams can be found in Figure 4 and 5. Note that MBC must be HIGH during Master Reset (until FFA/IRA and FFC/IRC go HIGH). MBA and MBB are "don't care" inputs1 during Master Reset. PARTIAL RESET (PRS1, PRS2) The FIFO1 memory of these devices undergoes a limited reset by taking its associated Partial Reset (PRS1) input LOW for at least four Port A Clock (CLKA) and four Port B Clock (CLKB) LOW-to-HIGH transitions. The FIFO2 memory undergoes a limited reset by taking its associated Partial Reset (PRS2) input LOW for at least four Port A Clock (CLKA) and four Port C Clock (CLKC) LOW-to-HIGH transitions. The RTM pin must be LOW during the time of partial reset. The Partial Reset inputs can switch asynchronously to the clocks. A Partial Reset initializes the internal read and write pointers and forces the Full/Input Ready flag (FFA/IRA, FFC/IRC) LOW, the Empty/Output Ready flag (EFA/ ORA, EFB/ORB) LOW, the Almost-Empty flag (AEA, AEB) LOW, and the Almost-Full flag (AFA, AFC) HIGH. A Partial Reset also forces the Mailbox Flag (MBF1, MBF2) of the parallel mailbox register HIGH. After a Partial Reset, the FIFO's Full/Input Ready flag is set HIGH after two Write Clock cycles. Whatever flag offsets, programming method (parallel or serial), and timing mode (FWFT or IDT Standard mode) are currently selected at the time a Partial Reset is initiated, those settings will remain unchanged upon completion of the reset operation. A Partial Reset may be useful in the case where reprogramming
a FIFO following a Master Reset would be inconvenient. See Figure 6 and 7 for Partial Reset timing diagrams. RETRANSMIT (RT1, RT2) The FIFO1 memory of these devices undergoes a Retransmit by taking its associated Retransmit (RT1) input LOW for at least four Port A Clock (CLKA) and four Port B Clock (CLKB) LOW-to-HIGH transitions. The Retransmit initializes the read pointer of FIFO1 to the first memory location. The FIFO2 memory undergoes a Retransmit by taking its associated Retransmit (RT2) input LOW for at least four Port A Clock (CLKA) and four Port C Clock (CLKC) LOW-to-HIGH transitions. The Retransmit initializes the read pointer of FIFO1 to the first memory location. The RTM pin must be HIGH during the time of Retransmit. Note that the RT1input is muxed with the PRS1 input, the state of the RTM pin determining whether this pin performs a Retransmit or Partial Reset. Also, the RT2 input is muxed with the PRS2 input, the state of the RTM pin determining whether this pin performs a Retransmit or Partial Reset. See Figures 30, 31, 32 and 33 for Retransmit timing diagrams. BIG-ENDIAN/FIRST WORD FALL THROUGH (BE/FWFT) -- ENDIAN SELECTION This is a dual purpose pin. At the time of Master Reset, the BE select function is active, permitting a choice of Big- or Little-Endian byte arrangement for data written to Port C or read from Port B. This selection determines the order by which bytes (or words) of data are transferred through those ports. For the following illustrations, note that both ports B and C are configured to have a byte (or a word) bus size. A HIGH on the BE/FWFT input when the Master Reset (MRS1, MRS2) inputs go from LOW to HIGH will select a Big-Endian arrangement. When data is moving in the direction from Port A to Port B, the most significant byte (word) of the long word written to Port A will be read from Port B first; the least significant byte (word) of the long word written to Port A will be read from Port B last. When data is moving in the direction from Port C to Port A, the byte (word) written to Port C first will be read from Port A as the most significant byte (word) of the long word; the byte (word) written to Port C last will be read from Port A as the least significant byte (word) of the long word. A LOW on the BE/FWFT input when the Master Reset (MRS1, MRS2) inputs go from LOW to HIGH will select a Little-Endian arrangement. When data is moving in the direction from Port A to Port B, the least significant byte (word) of the long word written to Port A will be read from Port B first; the most significant byte (word) of the long word written to Port A will be read from Port B last. When data is moving in the direction from Port C to Port A, the byte (word) written to Port C first will be read from Port A as the least significant byte (word) of the long word; the byte (word) written to Port C last will be read from Port A as the most significant byte (word) of the long word. Refer to Figure 2 and 3 for illustrations of the BE function. See Figure 4 (FIFO1 Master Reset) and 5 (FIFO2 Master Reset) for Endian Select timing diagrams. -- TIMING MODE SELECTION After Master Reset, the FWFT select function is available, permitting a choice between two possible timing modes: IDT Standard mode or First Word Fall Through (FWFT) mode. Once the Master Reset (MRS1, MRS2) input is HIGH, a HIGH on the BE/FWFT input during the next LOW-to-HIGH transition of CLKA (for FIFO1) and CLKC (for FIFO2) will select IDT Standard mode. This
NOTE: 1. Either a HIGH or LOW can be applied to a "don't care" input with no change to the logical operation of the FIFO. Nevertheless, inputs that are temporarily "don't care" (along with unused inputs) must not be left open, rather they must be either HIGH or LOW.
11
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
mode uses the Empty Flag function (EFA, EFB) to indicate whether or not there are any words present in the FIFO memory. It uses the Full Flag function (FFA, FFC) to indicate whether or not the FIFO memory has any free space for writing. In IDT Standard mode, every word read from the FIFO, including the first, must be requested using a formal read operation. Once the Master Reset (MRS1, MRS2) input is HIGH, a LOW on the BE/ FWFT input during the next LOW-to-HIGH transition of CLKA (for FIFO1) and CLKC (for FIFO2) will select FWFT mode. This mode uses the Output Ready function (ORA, ORB) to indicate whether or not there is valid data at the data outputs (A0-A35 or B0-B17). It also uses the Input Ready function (IRA, IRC) to indicate whether or not the FIFO memory has any free space for writing. In the FWFT mode, the first word written to an empty FIFO goes directly to the data outputs, no read request necessary. Subsequent words must be accessed by performing a formal read operation. Following Master Reset, the level applied to the BE/FWFT input to choose the desired timing mode must remain static throughout FIFO operation. Refer to Figure 4 (FIFO1 Master Reset) and Figure 5 (FIFO2 Master Reset) for First Word Fall Through select timing diagrams. PROGRAMMING THE ALMOST-EMPTY AND ALMOST-FULL FLAGS Four registers in these FIFOs are used to hold the offset values for the AlmostEmpty and Almost-Full flags. The Port B Almost-Empty flag (AEB) Offset register is labeled X1 and the Port A Almost-Empty flag (AEA) Offset register is labeled X2. The Port A Almost-Full flag (AFA) Offset register is labeled Y1 and the Port C Almost-Full flag (AFC) Offset register is labeled Y2. The index of each register name corresponds to its FIFO number. The Offset registers can be loaded with preset values during the reset of a FIFO, programmed in parallel using the FIFO's Port A data inputs, or programmed in serial using the Serial Data (SD) input (see Table 1). FS0/SD, FS1/SEN and FS2 function the same way in both IDT Standard and FWFT modes. -- PRESET VALUES To load a FIFO's Almost-Empty flag and Almost-Full flag Offset registers with one of the five preset values listed in Table 1, the flag select inputs must be HIGH
or LOW during a master reset. For example, to load the preset value of 64 into X1 and Y1, FS0, FS1 and FS2 must be HIGH when FlFO1 reset (MRS1) returns HIGH. Flag Offset registers associated with FIFO2 are loaded with one of the preset values in the same way with FIFO2 Master Reset (MRS2) toggled simultaneously with FIFO1 Master Reset (MRS1). For relevant Preset value loading timing diagrams, see Figure 4 and 5. -- PARALLEL LOAD FROM PORT A To program the X1, X2, Y1, and Y2 registers from Port A, perform a Master Reset on both FlFOs simultaneously with FS2 HIGH or LOW, FS0 and FS1 LOW during the LOW-to-HIGH transition of MRS1 and MRS2. The state of FS2 at this point of reset will determine whether the parallel programming method has Interspersed Parity or Non-Interspersed Parity. Refer to Table 1 for Flag Programming Flag Offset setup . It is important to note that once parallel programming has been selected during a Master Reset by holding both FS0 & FS1 LOW, these inputs must remain LOW during all subsequent FIFO operation. They can only be toggled HIGH when future Master Resets are performed and other programming methods are desired. After this reset is complete, the first four writes to FIFO1 do not store data in RAM but load the Offset registers in the order Y1, X1, Y2, X2. For NonInterspersed Parity mode the Port A data inputs used by the Offset registers are (A10-A0), (A11-A0), or (A12-A0) for the IDT72V3656, IDT72V3666, or IDT72V3676, respectively. For Interspersed Parity mode the Port A data inputs used by the Offset registers are (A11-A9, A7-A0), (A12-A9, A7-A0), or (A13A9, A7-A0) for the IDT72V3656, IDT72V3666, or IDT72V3676, respectively. The highest numbered input is used as the most significant bit of the binary number in each case. Valid programming values for the registers range from 1 to 2,044 for the IDT72V3656; 1 to 4,092 for the IDT72V3666; and 1 to 8,188 for the IDT72V3676. After all the Offset registers are programmed from Port A, the Port C Full/Input Ready flag (FFC/IRC) is set HIGH, and both FIFOs begin normal operation. Refer to Figure 8 for a timing diagram illustration for parallel programming of the flag offset values.
TABLE 1 FLAG PROGRAMMING
FS2
H H H H H H L L L L L H L
FS1/SEN
H H H H L L H H L L H L L
FS0/SD
H H L L H H H H H H L L L
MRS1
X X X X X
MRS2
X X X X X
X1 AND Y1 REGlSTERS(1)
64 X 16 X 8 X 256 X 1,024 X Serial programming via SD Parallel programming via Port A(3, 5) IP Mode(4, 5)
X2 AND Y2 REGlSTERS(2)
X 64 X 16 X 8 X 256 X 1,024 Serial programming via SD Parallel programming via Port A(3, 5) IP Mode(4, 5)
NOTES: 1. X1 register holds the offset for AEB; Y1 register holds the offset for AFA. 2. X2 register holds the offset for AEA; Y2 register holds the offset for AFC. 3. When this method of parallel programming is selected, Port A will assume Non-Interspersed Parity. 4. When IP Mode is selected, only parallel programming of the offset values via Port A, can be performed and Port A will assume Interspersed Parity. 5. IF parallel programming is selected during a Master Reset, then FS0 & FS1 must remain LOW during FIFO operation.
12
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
TABLE 2 PORT A ENABLE FUNCTION TABLE
CSA
H L L L L L L L L L
W/RA
X H H H L L L L H L
ENA
X L H H L H L H H H
MBA
X X L H L L H H L L
CLKA
X X X X
LOOP
H H H H H H H H L L
Data A(A0-A35) I/O
High-Impedance Input Input Input Output Output Output Output Output Output
PORT FUNCTION
None None FIFO1 write Mail1 write None FIFO2 read None Mail2 read (set MBF2 HIGH) Loop the data output of FIFO2 to input of FIFO1 only Loop the data output of FIFO2 to input of FIFO1 and put data on Port A
TABLE 3 PORT B ENABLE FUNCTION TABLE
CSB
H L L L L
RENB
X L H L H
MBB
X L L H H
CLKB
X X X
Data B (B0-B17) Outputs
High-Impedance Output Output Output Output
PORT FUNCTION
None None FIFO1 read None Mail1 read (set MBF1 HIGH)
TABLE 4 PORT C ENABLE FUNCTION TABLE
WENC
H H L L
MBC
L H L H
CLKC
X X
Data C (C0-C17) Inputs
Input Input Input Input
PORT FUNCTION
FIFO2 write Mail2 write None None
INTERSPERSED PARITY Interspersed Parity is selected during a Master Reset of the FIFO. Refer to Table 1 for the set-up configuration of Interspersed Parity. The Interspersed Parity function allows the user to select the location of the parity bits in the word loaded into the parallel port (A0-An) during programming of the flag offset values. If Interspersed Parity is selected then during parallel programming of the flag offset values, the device will ignore data line A8. If Non-Interspersed Parity is selected then data line A8 will become a valid bit. If Interspersed Parity is selected serial programming of the offset values is not permitted, only parallel programming can be done. -- SERIAL LOAD To program the X1, X2, Y1, and Y2 registers serially, initiate a Master Reset with FS2 LOW, FS0/SD LOW and FS1/SEN HIGH during the LOW-to-HIGH transition of MRS1 and MRS2. After this reset is complete, the X and Y register values are loaded bit-wise through the FS0/SD input on each LOW-to-HIGH transition of CLKA that the FS1/SEN input is LOW. There are 44-, 48-, or 52bit writes needed to complete the programming for the IDT72V3656, IDT7V3666, or IDT72V3676, respectively. The four registers are written in the order Y1, X1, Y2 and finally, X2. The first-bit write stores the most significant bit of the Y1 register and the last-bit write stores the least significant bit of the X2 register. Each register value can be programmed from 1 to 2,044 (IDT72V3656), 1 to 4,092 (IDT72V3666), or 1 to 8,188 (IDT72V3676).
When the option to program the Offset registers serially is chosen, the Port A Full/Input Ready (FFA/IRA) flag remains LOW until all register bits are written. FFA/IRA is set HIGH by the LOW-to-HIGH transition of CLKA after the last bit is loaded to allow normal FIFO1 operation. The Port B Full/Input Ready (FFC/ IRC) flag also remains LOW throughout the serial programming process, until all register bits are written. FFC/IRC is set HIGH by the LOW-to-HIGH transition of CLKC after the last bit is loaded to allow normal FIFO2 operation. See Figure 9 timing diagram, Serial Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes). FIFO WRITE/READ OPERATION The state of the Port A data (A0-A35) outputs is controlled by Port A Chip Select (CSA) and 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/IRA 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/ORA is HIGH (see Table 2). FIFO reads and writes on Port A are independent of any concurrent Port B or Port C operation.
13
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
The state of the Port B data (B0-B17) outputs is controlled by the Port B Chip Select (CSB). The B0-B17 outputs are in the high-impedance state when CSB is HIGH. The B0-B17 outputs are active when CSB is LOW. Data is read from FIFO1 to the B0-B17 outputs by a LOW-to-HIGH transition of CLKB when CSB is LOW, RENB is HIGH, MBB is LOW and EFB/ ORB is HIGH (see Table 3). FIFO reads on Port B are independent of any concurrent Port A and Port C operations. Data is loaded into FIFO2 from the C0-C17 inputs on a LOW-to-HIGH transition of CLKC when WENB is HIGH, MBC is LOW, and FFC/IRC is HIGH (see Table 4). FIFO writes on Port C are independent of any concurrent Port A and Port B operation. The setup and hold time constraints for CSA and W/RA with regard to CLKA as well as CSB with regard to CLKB are only for enabling write and read operations and are not related to high-impedance control of the data outputs. If ENA is LOW during a clock cycle, either CSA or W/RA may change states during the setup and hold time window of the cycle. This is also true for CSB when RENB is LOW. When operating the FIFO in FWFT mode and the Output Ready flag is LOW, the next word written is automatically sent to the FIFO's output register by the LOW-to-HIGH transition of the port clock that sets the Output Ready flag HIGH. When the Output Ready flag is HIGH, subsequent data is clocked to the output registers only when a read is selected using CSA, W/RA, ENA and MBA at Port A or using CSB, RENB and MBB at Port B. When operating the FIFO in IDT Standard mode, the first word will cause the Empty Flag to change state on the second LOW-to-HIGH transition of the
Read Clock. The data word will not be automatically sent to the output register. Instead, data residing in the FIFO's memory array is clocked to the output register only when a read is selected using CSA, W/RA, ENA and MBA at Port A or using CSB, RENB and MBB at Port B. Relevant write and read timing diagrams for Port A can be found in Figure 10 and 15. Relevant read and write timing diagrams for Port B and Port C, together with Bus-Matching and Endian select operation, can be found in Figure 11 to 14. LOOPBACK (LOOP) A Loopback function is provided on Port A and is selected by setting the LOOP pin LOW. When the Loop feature is selected, the data output from FIFO2 will be directed to the data input of FIFO1. If Loop is selected and Port A is setup for write operation via the W/RA pin being HIGH, then data output from FIFO2 will be written to FIFO1, on every LOW-to-HIGH transition of CLKA, provided CSA is LOW and ENA is HIGH. However, FIFO2 data output will not be placed on the output Port A (A0-A35). If Port A is set-up for read operation via the W/ RA pin being LOW, then data output from FIFO2 will be written into FIFO1 on every LOW-to-HIGH transition of CLKA, provided CSA is LOW and ENA is HIGH. Also FIFO2 data will be output to Port A (A0-A35). When the LOOP pin is HIGH then Port A operates in the normal manner. Refer to Table 2 for the input set-up of the Loop feature. The Loop operation will continue to happen provided that FIFO1 is not full and FIFO2 is not empty. If during a Loop sequence FIFO1 becomes full then any data that continues to be read out from FIFO2 will only be placed on the Port A (A0-A35) lines, (provided that Port A is set-up for read operation). If
TABLE 5 FIFO1 FLAG OPERATION (IDT Standard and FWFT modes)
Number of Words in FIFO Memory(1,2) IDT72V3656(3) 0 1 to X1 (X1+1) to [2,048-(Y1+1)] (2,048-Y1) to 2,047 2,048 IDT72V3666(3) 0 1 to X1 (X1+1) to [4,096-(Y1+1)] (4,096-Y1) to 4,095 4,096 IDT72V3676(3) 0 1 to X1 (X1+1) to [8,192-(Y1+1)] (8,192-Y1) to 8,191 8,192 Synchronized to CLKB EFB/ORB L H H H H AEB L L H H H Synchronized to CLKA AFA H H H L L FFA/IRA H H H H L
NOTES: 1. When a word loaded to an empty FIFO is shifted to the output register, its previous FIFO memory location is free. 2. Data in the output register does not count as a "word in FIFO memory". Since in FWFT mode, the first word written to an empty FIFO goes unrequested to the output register (no read operation necessary), it is not included in the FIFO memory count. 3. X1 is the almost-empty offset for FIFO1 used by AEB. Y1 is the almost-full offset for FIFO1 used by AFA. Both X1 and Y1 are selected during a FIFO1 reset or port A programming. 4. The ORB and IRA functions are active during FWFT mode; the EFB and FFA functions are active in IDT Standard mode.
TABLE 6 FIFO2 FLAG OPERATION (IDT Standard and FWFT modes)
Number of Words in FIFO Memory(1,2) IDT72V3656(3) 0 1 to X2 (X2+1) to [2,048-(Y2+1)] (2,048-Y2) to 2,047 2,048 IDT72V3666(3) 0 1 to X2 (X2+1) to [4,096-(Y2+1)] (4,096-Y2) to 4,095 4,096 IDT72V3676(3) 0 1 to X2 (X2+1) to [8,192-(Y2+1)] (8,192-Y2) to 8,191 8,192 Synchronized to CLKA EFA/ORA L H H H H AEA L L H H H Synchronized to CLKC AFC H H H L L FFC/IRC H H H H L
NOTES: 1. When a word loaded to an empty FIFO is shifted to the output register, its previous FIFO memory location is free. 2. Data in the output register does not count as a "word in FIFO memory". Since in FWFT mode, the first word written to an empty FIFO goes unrequested to the output register (no read operation necessary), it is not included in the FIFO memory count. 3. X2 is the almost-empty offset for FIFO2 used by AEA. Y2 is the almost-full offset for FIFO2 used by AFC. Both X2 and Y2 are selected during a FIFO2 reset or port A programming. 4. The ORA and IRC functions are active during FWFT mode; the EFA and FFC functions are active in IDT Standard mode.
14
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
during a Loop sequence the FIFO2 becomes empty, then the last word from FIFO2 will continue to be clocked into FIFO1 until FIFO1 becomes full or until the Loop function is stopped. The Loop feature can be useful when performing system debugging and remote loopbacks. See Figures 34 and 35 for Loopback timing diagrams. SYNCHRONIZED FIFO FLAGS Each FIFO is synchronized to its port clock through at least two flip-flop stages. This is done to improve flag signal reliability by reducing the probability of metastable events when CLKA operates asynchronously with respect to either CLKB or CLKC. EFA/ORA, AEA, FFA/IRA, and AFA are synchronized to CLKA. EFB/ORB and AEB are synchronized to CLKB. FFC/IRC and AFC are synchronized to CLKC. Tables 5 and 6 show the relationship of each port flag to FIFO1 and FIFO2. EMPTY/OUTPUT READY FLAGS (EFA/ORA, EFB/ORB) These are dual purpose flags. In the FWFT mode, the Output Ready (ORA, ORB) function is selected. When the Output Ready flag is HIGH, new data is present in the FIFO output register. When the Output Ready flag is LOW, the previous data word is present in the FIFO output register and attempted FIFO reads are ignored. In the IDT Standard mode, the Empty Flag (EFA, EFB) function is selected. When the Empty Flag is HIGH, data is available in the FIFO's RAM memory for reading to the output register. When the Empty Flag is LOW, the previous data word is present in the FIFO output register and attempted FIFO reads are ignored. The Empty/Output Ready flag of a FIFO is synchronized to the port clock that reads data from its array. For both the FWFT and IDT Standard modes, the FIFO read pointer is incremented each time a new word is clocked to its output register. The state machine that controls an Output Ready flag monitors a write pointer and read pointer comparator that indicates when the FIFO memory status is empty, empty+1, or empty+2. In FWFT mode, from the time a word is written to a FIFO, it can be shifted to the FIFO output register in a minimum of three cycles of the Output Ready flag synchronizing clock. Therefore, an Output Ready flag is LOW if a word in memory is the next data to be sent to the FlFO output register and three cycles of the port clock that reads data from the FIFO have not elapsed since the time the word was written. The Output Ready flag of the FIFO remains LOW until the third LOW-to-HIGH transition of the synchronizing clock occurs, simultaneously forcing the Output Ready flag HIGH and shifting the word to the FIFO output register. In IDT Standard mode, from the time a word is written to a FIFO, the Empty Flag will indicate the presence of data available for reading in a minimum of two 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 FlFO 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 remains LOW until the second LOW-to-HIGH transition of the synchronizing clock occurs, forcing the Empty Flag HIGH; only then can data be read. A LOW-to-HIGH transition on an Empty/Output Ready 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 16, 17, 18 and 19). FULL/INPUT READY FLAGS (FFA/IRA, FFC/IRC) These are dual purpose flags. In FWFT mode, the Input Ready (IRA and IRC) function is selected. In IDT Standard mode, the Full Flag (FFA and FFC)
function is selected. For both timing modes, when the Full/Input Ready flag is HIGH, a memory location is free in the FIFO to receive new data. No memory locations are free when the Full/Input Ready flag is LOW and attempted writes to the FIFO are ignored. The Full/Input Ready flag of a FlFO is synchronized to the port clock that writes data to its array. For both FWFT and IDT Standard modes, each time a word is written to a FIFO, its write pointer is incremented. The state machine that controls a Full/Input Ready flag monitors a write pointer and read pointer comparator that indicates when the FlFO memory status is full, full-1, or full-2. From the time a word is read from a FIFO, its previous memory location is ready to be written to in a minimum of two cycles of the Full/Input Ready flag synchronizing clock. Therefore, an Full/Input Ready flag is LOW if less than two cycles of the Full/Input Ready flag synchronizing clock have elapsed since the next memory write location has been read. The second LOW-to-HIGH transition on the Full/Input Ready flag synchronizing clock after the read sets the Full/Input Ready flag HIGH. A LOW-to-HIGH transition on a Full/Input Ready 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 20, 21, 22, and 23). 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 read pointer comparator that indicates when the FIFO memory status is almost-empty, almost-empty+1, or almost-empty+2. The almost-empty state is defined by the contents of register X1 for AEB and register X2 for AEA. These registers are loaded with preset values during a FIFO reset, programmed from Port A, or programmed serially (see the Almost-Empty flag and Almost-Full flag offset programming section). An Almost-Empty flag is LOW when its FIFO contains X or less words and is HIGH when its FIFO contains (X+1) or more words. A data word present in the FIFO output register has been read from memory. Two LOW-to-HIGH transitions of the Almost-Empty flag synchronizing clock are required after a FIFO write for its Almost-Empty flag to reflect the new level of fill. Therefore, the Almost-Full flag of a FIFO containing (X+1) or more words remains LOW if two cycles of its 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 its synchronizing clock after the FIFO write that fills memory to the (X+1) level. A LOW-to-HIGH transition of an AlmostEmpty flag synchronizing clock begins the first synchronization cycle if it occurs at time tSKEW2 or greater after the write that fills the FIFO to (X+1) words. Otherwise, the subsequent synchronizing clock cycle may be the first synchronization cycle. (See Figure 24 and 25). ALMOST-FULL FLAGS (AFA, AFC) 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 memory status is almost-full, almost-full-1, or almost-full-2. The almost-full state is defined by the contents of register Y1 for AFA and register Y2 for AFC. These registers are loaded with preset values during a FlFO reset, programmed from Port A, or programmed serially (see Almost-Empty flag and Almost-Full flag offset programming section). An Almost-Full flag is LOW when the number of words in its FIFO is greater than or equal to (2,048-Y), (4,096-Y), or (8,192-Y) for the IDT72V3656, IDT72V3666, or IDT72V3676 respectively. An Almost-Full flag is HIGH when the number of words in its FIFO is less than or equal to [2,048-
15
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
(Y+1)], [4,096-(Y+1)], or [8,192-(Y+1)] for the IDT72V3656, IDT72V3666, or IDT72V3676 respectively. Note that a data word present in the FIFO output register has been read from memory. Two LOW-to-HIGH transitions of the Almost-Full flag synchronizing clock are required after a FIFO read for its Almost-Full flag to reflect the new level of fill. Therefore, the Almost-Full flag of a FIFO containing [2,048/4,096/8,192(Y+1)] or less words remains LOW if two cycles of its synchronizing clock have not elapsed since the read that reduced the number of words in memory to [2,048/4,096/8,192-(Y+1)]. An Almost-Full flag is set HIGH by the second LOW-to-HIGH transition of its synchronizing clock after the FIFO read that reduces the number of words in memory to [2,048/4,096/8,192-(Y+1)]. A LOWto-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 words in memory to [2,048/4,096/8,192-(Y+1)]. Otherwise, the subsequent synchronizing clock cycle may be the first synchronization cycle (see Figure 26 and 27). MAILBOX REGISTERS Each FIFO has an 18-bit bypass register allowing the passage of command and control information from Port A to Port B or from Port C to Port A without putting it in queue. The Mailbox Select (MBA, MBB and MBC) inputs choose between a mail register and a FIFO for a port data transfer operation. The usable width of both the Mail1 and Mail2 registers matches the selected bus size for ports B and C. When sending data from Port A to Port B via the Mail1 Register, the following is the case: A LOW-to-HIGH transition on CLKA writes data to the Mail1 Register when a Port A write is selected by CSA, W/RA, and ENA with MBA HIGH. If the selected Port B bus size is 18 bits, then the usable width of the Mail1 Register employs data lines A0-A17. (In this case, A18-A35 are don't care inputs.) If the selected Port B bus size is 9 bits, then the usable width of the Mail1 Register employs data lines A0-A8. (In this case, A9-A35 are don't care inputs.) When sending data from Port C to Port A via the Mail2 Register, the following is the case: A LOW-to-HIGH transition on CLKC writes data to the Mail2 Register when a Port C write is selected by WENC with MBC HIGH. If the selected Port C bus size is 18 bits, then the usable width of the Mail2 Register employs data lines C0-C17. If the selected Port C bus size is 9 bits, then the usable width of the Mail2 Register employs data lines C0-C8. (In this case, C9-C17 are don't care inputs.) Writing data to a mail register sets its corresponding flag (MBF1 or MBF2) LOW. Attempted writes to a mail register are ignored while the mail flag is LOW. When data outputs of a port are active, the data on the bus comes from the FIFO output register when the port Mailbox select input is LOW and from the mail register when the port mailbox select input is HIGH. The Mail1 Register Flag (MBF1) is set HIGH by a LOW-to-HIGH transition on CLKB when a Port B read is selected by CSB, and RENB with MBB HIGH. For an 18-bit bus size, 18 bits of mailbox data are placed on B0-B17. For the 9-bit bus size, 9 bits of mailbox data are placed on B0-B8. (In this case, B9-B17 are indeterminate.) The Mail2 Register Flag (MBF2) is set HIGH by a LOW-to-HIGH transition on CLKA when a Port A read is selected by CSA, W/RA, and ENA with MBA HIGH. The data in a mail register remains intact after it is read and changes only when new data is written to the register. For an 18-bit bus size, 18 bits of mailbox data appear on A18-A35. (In this case, A0-A17 are indeterminate.) For a 9bit bus size, 9 bits of mailbox data appear on A18-A26. (In this case, A0-A17 and A27-A35 are indeterminate.) The data in a mail register remains intact after it is read and changes only when new data is written to the register. The Endian Select feature has no effect on mailbox data.
16
Note that MBC must be HIGH during Master Reset (until FFA/IRA and FFC/ IRC go HIGH. MBA and MBB are don't care inputs during Master Reset. For mail register and mail register flag timing diagrams, see Figure 28 and 29. BUS SIZING Port B may be configured in either an 18-bit word or a 9-bit byte format for data read from FIFO1. Port C may be configured in either an 18-bit word or a 9-bit byte format for data written to FIFO2. The bus size can be selected independently for Ports B and C. The level applied to the Port B Size Select (SIZEB) input determines the Port B bus size and the level applied to the Port C Size Select (SIZEC) input determines the Port C bus size. These levels should be static throughout FIFO operation. Both bus size selections are implemented at the completion of Master Reset, by the time the Full/Input Ready flag is set HIGH, as shown in Figure 2 and 3. Two different methods for sequencing data transfer are available for Ports B and C regardless of whether the bus size selection is byte- or word-size. They are referred to as Big-Endian (most significant byte first) and Little-Endian (least significant byte first). The level applied to the Big-Endian Select (BE) input during the LOW-to-HIGH transition of MRS1 and MRS2 selects the endian method that will be active during FIFO operation. This selection applies to both ports B and C. The endian method is implemented at the completion of Master Reset, by the time the Full/Input Ready flag is set HIGH, as shown in Figure 2 and 3 (see Endian Selection section). Only 36-bit long word data is written to or read from the two FIFO memories on these devices. Bus-Matching operations are done after data is read from the FIFO1 RAM (Port B) and before data is written to the FIFO2 RAM (Port C). The Endian select operations are not available when transferring data via mailbox registers. Furthermore, both the word- and byte-size bus selections limit the width of the data bus that can be used for mail register operations. In this case, only those byte lanes belonging to the selected word- or byte-size bus can carry mailbox data. The remaining data outputs will be indeterminate. The remaining data inputs will be don't care inputs. For example, when a wordsize bus is selected on Port B, then mailbox data can be transmitted only from A0-A17 to B0-B17. When a byte-size bus is selected on Port B, then mailbox data can be transmitted only from A0-A8 to B0-B8. Similarly, when a word-size bus is selected on Port C, then mailbox data can be transmitted only from C0C17 to A18-A35. When a byte-size bus is selected on Port C, then mailbox data can be transmitted only from C0-C8 to A18-A26. BUS-MATCHING FIFO1 READS Data is read from the FIFO1 RAM in 36-bit long word increments. Since Port B can have a byte or word size, 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 output the rest of the long word to the FIFO1 output register in the order shown by Figure 2. When reading data from FIFO1 in byte format, the unused B9-B17 outputs are indeterminate. BUS-MATCHING FIFO2 WRITES Data is written to the FIFO2 RAM in 36-bit long word increments. Data written to FIFO2 with a byte or word bus size stores the initial bytes or words in auxiliary registers. The CLKC rising edge that writes the fourth byte or the second word of long word to FIFO2 also stores the entire long word in the FIFO2 memory. The bytes are arranged in the manner shown in Figure 3. When writing data to FIFO2 in byte format, the unused C9-C17 inputs are don't care inputs.
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
BYTE ORDER ON PORT A:
COMMERCIAL TEMPERATURE RANGE
A8 A0
A35A27
A26A18
A17A9
A
B
C
D
Write to FIFO1
BYTE ORDER ON PORT B:
B17B9
B8 B0
BE H
SIZEB L
A
B17B9
B
B8 B0
1st: Read from FIFO1
C
D
2nd: Read from FIFO1
(b) WORD SIZE BIG ENDIAN
B17B9 BE L SIZEB L B17B9
B8 B0
C
D
B8 B0
1st: Read from FIFO1
A
B
2nd: Read from FIFO1
(c) WORD SIZE LITTLE ENDIAN
B17B9 BE H SIZEB H B17B9
B8 B0
A
B8 B0
1st: Read from FIFO1
B
B17B9 B8 B0
2nd: Read from FIFO1
C
B17B9 B8 B0
3rd: Read from FIFO1
D
(d) BYTE SIZE BIG ENDIAN
4th: Read from FIFO1
B17B9 BE L SIZEB H B17B9
B8 B0
D
B8 B0
1st: Read from FIFO1
C
B17B9 B8 B0
2nd: Read from FIFO1
B
B17B9 B8 B0
3rd: Read from FIFO1
A
(e) BYTE SIZE LITTLE ENDIAN
4th: Read from FIFO1
4665 drw 03
Figure 2. Port B Bus Sizing
17
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
BYTE ORDER ON PORT A:
COMMERCIAL TEMPERATURE RANGE
A8 A0
A35A27
A26A18
A17A9
A
B
C
D
Read from FIFO2
BYTE ORDER ON PORT C:
C17 C9
C8 C0
BE H
SIZEC L
A
C17 C9
B
C8 C0
1st: Write to FIFO2
C
D
2nd: Write to FIFO2
(b) WORD SIZE BIG ENDIAN
C17 C9 BE L SIZEC L C17 C9
C8 C0
C
D
C8 C0
1st: Write to FIFO2
A
B
2nd: Write to FIFO2
(c) WORD SIZE LITTLE ENDIAN
C17 C9 BE H SIZEC H C17 C9
C8 C0
A
C8 C0
1st: Write to FIFO2
B
C17 C9 C8 C0
2nd: Write to FIFO2
C
C17 C9 C8 C0
3rd: Write to FIFO2
D
(d) BYTE SIZE BIG ENDIAN
4th: Write to FIFO2
C17 C9 BE L SIZEC H C17 C9
C8 C0
D
C8 C0
1st: Write to FIFO2
C
C17 C9 C8 C0
2nd: Write to FIFO2
B
C17 C9 C8 C0
3rd: Write to FIFO2
A
(e) BYTE SIZE LITTLE ENDIAN
4th: Write to FIFO2
4665 drw 04
Figure 3. Port C Bus Sizing
18
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
CLKA CLKB tRSTS MRS1 tBES BE/FWFT tFSS FS2,FS1 ,FS0 FFA/IRA tREF EFB/ORB tRSF AEB tRSF AFA tRSF MBF1 RTM LOOP LOW HIGH
(2) 1 2
COMMERCIAL TEMPERATURE RANGE
tRSTH tBEH BE tFSH 0,1 tWFF tWFF
tFWS FWFT
4665 drw 05
NOTES: 1. PRS1 and MBC must be HIGH during Master Reset until the rising edge of FFA/IRA goes HIGH. 2. If BE/FWFT is HIGH, then EFB/ORB will go LOW one CLKB cycle earlier than in this case where BE/FWFT is LOW.
Figure 4. FIFO1 Master Reset and Loading X1 and Y1 with a Preset Value of Eight (IDT Standard and FWFT Modes)
CLKC CLKA tRSTS MRS2(3) BE/FWFT
1
2
tRSTH tBES BE tFSS tFSH 0,1 tWFF tREF
(2)
tBEH
tFWS FWFT
FS2,FS1 ,FS0 FFC/IRC EFA/ORA tRSF AEA tRSF AFC tRSF MBF2 RTM LOOP LOW HIGH
tWFF
4665 drw06
NOTES: 1. PRS2 and MBC must be HIGH during Master Reset until the rising edge of FFC/IRC goes HIGH. 2. If BE/FWFT is HIGH, then EFA/ORA will go LOW one CLKA cycle earlier than in this case where BE/FWFT is LOW. 3. MRS2 must toggle simultaneously with MRS1.
Figure 5. FIFO2 Master Reset and Loading X2 and Y2 with a Preset Value of Eight (IDT Standard and FWFT Modes)
19
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
CLKA CLKB tRSTS PRS1 tWFF FFA/IRA tREF EFB/ORB tRSF AEB tRSF AFA tRSF MBF1 RTM LOW
(2) 1 2
COMMERCIAL TEMPERATURE RANGE
tRSTH tWFF
4665 drw 07
NOTES: 1. MRS1 must be HIGH during Partial Reset. 2. If BE/FWFT is HIGH, then EFB/ORB will go LOW one CLKB cycle earlier than in this case where BE/FWFT is LOW.
Figure 6. FIFO1 Partial Reset (IDT Standard and FWFT Modes)
CLKC
CLKA tRSTS PRS2 tWFF tWFF FFC/IRC tREF (2) EFA/ORA tRSF AEA tRSF AFC tRSF MBF1
NOTES: 1. MRS2 must be HIGH during Partial Reset. 2. If BE/FWFT is HIGH, then EFA/ORA will go LOW one CLKA cycle earlier than in this case where BE/FWFT is LOW.
4665 drw 08
tRSTH
Figure 7. FIFO2 Partial Reset (IDT Standard and FWFT Modes)
20
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA MRS1, MRS2 tFSS FS2 tFSS FS1,FS0 FFA/IRA
4
tFSH
tFSH 0,0 tWFF tENS2 tENH tSKEW1 (1)
ENA tDS A0-A35
AFA Offset (Y1) AEB Offset (X1) AFC Offset (Y2) AEA Offset (X2) First Word to FIFO1
tDH
CLKC
1
2 tWFF
FFC/IRC
4665 drw09
NOTES: 1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKC edge for FFC/IRC to transition HIGH in the next cycle. If the time between the rising edge of CLKA and rising edge of CLKC is less than tSKEW1, then FFC/IRC may transition HIGH one CLKC cycle later than shown. 2. CSA = LOW, W/RA = HIGH, MBA = LOW. It is not necessary to program Offset register on consecutive clock cycles.
Figure 8. Parallel Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes)
CLKA MRS1, MRS2 tFSS FS2
4
tFSH
tWFF FFA/IRA tFSS FS1/SEN tSDS FS0/SD(3) AFA Offset (Y1) MSB CLKC 4 tWFF FFC/IRC
4665 drw 10
tSKEW(1) tSPH tSENS tSENH tSENS tSENH
tSDH
tSDS
tSDH
AEA Offset (X2) LSB
NOTES: 1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKC edge for FFC/IRC to transition HIGH in the next cycle. If the time between the rising edge of CLKA and rising edge of CLKC is less than tSKEW1, then FFC/IRC may transition HIGH one CLKC cycle later than shown. 2. It is not necessary to program Offset register bits on consecutive clock cycles. FIFO write attempts are ignored until FFA/IRA, FFC/IRC is set HIGH. 3. Programmable offsets are written serially to the SD input in the order AFA offset (Y1), AEB offset (X1), AFC offset (Y2), and AEA offset (X2).
Figure 9. Serial Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes)
21
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH CLKA FFA/IRA HIGH CSA W/RA tENS2 MBA tENS2 ENA A0-A35
NOTE: 1. Written to FIFO1.
tCLKL
tENS1 tENS1
tENH tENH
tENH tENH tDH W2(1) No Operation
4665 drw11
tENS2
tENH
tENS2
tENH
tDS W1(1)
Figure 10. Port A Write Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
CLKC FFC/IRC HIGH MBC tENS2 WENC tDS C0-C17
4665 drw12
tENS2
tENH tENH tDH
tENS2 tENS2
tENH tENH
DATA SIZE TABLE FOR WORD WRITES TO FIFO2
SIZE MODE(1) SIZEC L BE H 1 2 1 2 WRITE NO. DATA WRITTEN TO FIFO2 C17-C9 A C C A C8-C0 B D D B A35-A27 A A26-A18 B A17-A9 C A8-A0 D DATA READ FROM FIFO2
L
L
A
B
C
D
NOTE: 1. BE is selected at Master Reset; SIZEB and SIZEC must be static throughout device operation.
Figure 11. Port C Word Write Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
22
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKC FFC/IRC HIGH MBC tENS2 WENC tDS C0-C8
4665 drw 13
tENS2
tENH tENH tDH tENS2
tENH tENH
DATA SIZE TABLE FOR BYTE WRITES TO FIFO2
SIZE MODE(1) SIZEC BE 1 2 3 4 1 2 3 4 WRITE NO. DATA WRITTEN TO FIFO2 C8-C0 A B C D D C B A DATA READ FROM FIFO2 A35-A27 A26-A18 A17-A9 A8-A0
H
H
A
B
C
D
H
L
A
B
C
D
NOTE: 1. BE is selected at Master Reset; SIZEB and SIZEC must be static throughout device operation.
Figure 12. Port C Byte Write Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
CLKB EFB/ORB CSB MBB tENS2 RENB B0-B17
(Standard Mode)
HIGH
tENH No Operation Read 2 tA Read 2 Read 3
4665 drw 14
tEN tEN
tMDV tMDV
tA Previous Data tA Read 1
tA Read 1
tDIS tDIS
OR B0-B17
(FWFT Mode)
DATA SIZE TABLE FOR WORD READS FROM FIFO1
SIZE MODE(1) DATA WRITTEN TO FIFO1 BE H L A35-A27 A A A26-A18 B B A17-A9 C C A8-A0 D D READ NO. 1 2 1 2 DATA READ FROM FIFO1 B17-B9 A C C A B8-B0 B D D B SIZEB H H
NOTE: 1. BE is selected at Master Reset; SIZEB and SIZEC must be static throughout device operation.
Figure 13. Port B Word Read Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
23
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
CLKB EFB/ORB HIGH CSB MBB tENS2 RENB B0-B8
(Standard Mode) OR
COMMERCIAL TEMPERATURE RANGE
tENH
No Operation
tEN
tMDV
tA Previous Data tA Read 1
tA Read 1 tA Read 2
tA Read 2 tA Read 3
tA Read 3 tA Read 4
tDIS tDIS
Read 4 Read 5
4665 drw 15
B0-B8
(FWFT Mode)
tEN
tMDV
NOTE: 1. Unused bytes B9-B17 are indeterminate for byte-size reads.
DATA SIZE TABLE FOR BYTE READS FROM FIFO1
SIZE MODE(1) SIZEB BE A35-A27 DATA WRITTEN TO FIFO1 A26-A18 A17-A9 A8-A0 1 2 3 4 1 H L A B C D 2 3 4
NOTE: 1. BE is selected at Master Reset; SIZEB must be static throughout device operation.
READ NO.
DATA READ FROM FIFO1 B8-B0 A B C D D C B A
H
H
A
B
C
D
Figure 14. Port B Byte Read Cycle Timing for FIFO1 (IDT Standard and FWFT Modes)
tCLKH CLKA EFA/ORA CSA W/RA
tCLK tCLKL
HIGH
MBA tENS2 ENA tMDV A0-A35 (Standard Mode) OR A0-A35
(FWFT Mode)
tENH
tENS2
tENH
tENS2 No Operation W2(1)
tENH tDIS tDIS
tEN tEN tMDV
tA Previous Data tA W1(1) W2(1) W1(1)
tA
tA W3(1)
4665 drw16
NOTE: 1. Read From FIFO2.
Figure 15. Port A Read Cycle Timing for FIFO2 (IDT Standard and FWFT Modes)
24
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH tCLKL CLKA CSA LOW WRA MBA tENS2 ENA IRA HIGH A0-A35 CLKB ORB CSB MBB RENB tA B0-B17 tA
Read 1 Read 2
4665 drw17
HIGH
tENS2
tENH tENH
tDS W1
tDH
(1)
tSKEW1
tCLK tCLKH tCLKL 1
2
3 tREF tREF
FIFO1 Empty LOW LOW tENS2 tENH
NOTES: 1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKB edge for ORB to transition HIGH and to clock the next word to the FIFO1 output register in three CLKB cycles. If the time between the rising CLKA edge and rising CLKB edge is less than tSKEW1, then the transition of ORB HIGH and load of the first word to the output register may occur one CLKB cycle later than shown. 2. If Port B size is word or byte, ORB is set LOW by the last word or byte read from FIFO1, respectively (the word-size case is shown).
Figure 16. ORB Flag Timing and First Data Word Fall Through when FIFO1 is Empty (FWFT Mode)
25
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH tCLKL CLKA CSA WRA MBA tENS2 ENA FFA A0-A35 CLKB EFB CSB MBB RENB tA B0-B17 tA
Read 1 Read 2
4665 drw18
LOW HIGH tENS2 tENH tENH
HIGH
tDS W1
tDH
(1)
tSKEW1
tCLK tCLKH tCLKL 1
2 tREF tREF
FIFO1 Empty LOW LOW tENS2 tENH
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. If Port B size is word or byte, EFB is set LOW by the last word or byte read from FIFO1, respectively (the word-size case is shown).
Figure 17. EFB Flag Timing and First Data Read Fall Through when FIFO1 is Empty (IDT Standard Mode)
26
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH tCLKL CLKC tENS2 MBC tENS2 WENC IRC C0-C17 CLKA ORA CSA W/RA MBA ENA tA A0-A35 Old Data in FIFO2 Output Register W1
4665 drw19
tENH tENH
HIGH tDS
Write 1
tDH tDS
Write 2
tDH
(1)
tSKEW1
tCLK tCLKH tCLKL 1
2
3
tREF
tREF
FIFO2 Empty LOW LOW LOW tENS2 tENH
NOTES: 1. tSKEW1 is the minimum time between a rising CLKC edge and a rising CLKA edge for ORA to transition HIGH and to clock the next word to the FIFO2 output register in three CLKA cycles. If the time between the CLKC edge and the rising CLKA edge is less than tSKEW1, then the transition of ORA HIGH and load of the first word to the output register may occur one CLKA cycle later than shown. 2. If Port C size is word or byte, tSKEW1 is referenced to the rising CLKC edge that writes the last word or byte write of the long word, respectively.
Figure 18. ORA Flag Timing and First Data Word Fall through when FIFO2 is Empty (FWFT Mode)
27
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH tCLKL CLKC tENS2 MBC tENS2 WENC FFC HIGH tDS C0-C17 CLKA EFA FIFO2 Empty CSA LOW W/RA LOW MBA LOW tENS2 ENA tA A0-A35 W1
4665 drw20
tENH tENH
tDH tDS
Write 2
tDH
(1)
Write 1
tSKEW1
tCLK tCLKH tCLKL 1
2 tREF tREF
tENH
NOTES: 1. tSKEW1 is the minimum time between a rising CLKC edge and a rising CLKA edge for EFA to transition HIGH in the next CLKA cycle. If the time between the rising CLKC edge and rising CLKA edge is less than tSKEW1, then the transition of EFA HIGH may occur one CLKA cycle later than shown. 2. If Port C size is word or byte, tSKEW1 is referenced to the rising CLKC edge that writes the last word or byte of the long word, respectively.
Figure 19. EFA Flag Timing and First Data Read when FIFO2 is Empty (IDT Standard Mode)
28
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH CLKB CSB LOW tCLKL
MBB LOW tENS2 RENB ORB B0-B17
Previous Word in FIFO1 Output Register
tENH
HIGH
tA
Read 1
tA
Read 2
tSKEW1
(1)
CLKA IRA CSA FIFO1 Full LOW
tCLKH 1
tCLK
tCLKL 2 tWFF tWFF
W/RA MBA
HIGH
tENS2
tENH tENH
tENS2 ENA tDS A0-A35
Write To FIFO1
tDH
4665 drw21
NOTES: 1. tSKEW1 is the minimum time between a rising CLKB edge and a rising CLKA edge for IRA 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 IRA may transition HIGH one CLKA cycle later than shown. 2. If Port B size is word or byte, tSKEW1 is referenced to the rising CLKB edge that reads the last word or byte write of the long word, respectively (the word-size case is shown).
Figure 20. IRA Flag Timing and First Available Write when FIFO1 is Full (FWFT Mode)
29
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH CLKB CSB LOW MBB LOW tENS2 RENB tCLKL
tENH
EFB HIGH B0-B17
tA
Read 1
tA
Read 2
Previous Word in FIFO1 Output Register
tSKEW1
(1)
CLKA FFA FIFO1 Full CSA W/RA MBA LOW HIGH
tCLKH 1
tCLK
tCLKL 2 tWFF tWFF
tENS2 tENS2
tENH tENH tDH
Write To FIFO1
4665 drw22
ENA tDS A0-A35
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. 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 (the word-size case is shown).
Figure 21. FFA Flag Timing and First Available Write when FIFO1 is Full (IDT Standard Mode)
30
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH CLKA CSA W/RA MBA ENA ORA A0-A35 HIGH LOW LOW LOW tENS2 tENH tCLKL
tA
Next Word From FIFO2
(1)
Previous Word in FIFO2 Output Register
tSKEW1 CLKC IRC FIFO2 Full
tCLKH 1
tCLK
tCLKL 2 tWFF tENS2 tWFF tENH tENH tDH
Write To FIFO2
4665 drw23
MBC tENS2 WENC tDS C0-C17 tDS tDH
NOTES: 1. tSKEW1 is the minimum time between a rising CLKC edge and a rising CLKC edge for IRC to transition HIGH in the next CLKC cycle. If the time between the rising CLKA edge and rising CLKC edge is less than tSKEW1, then IRC may transition HIGH one CLKC cycle later than shown. 2. If Port C size is word or byte, IRC is set LOW by the last word or byte write of the long word, respectively (the word-size case is shown).
Figure 22. IRC Flag Timing and First Available Write when FIFO2 is Full (FWFT Mode)
31
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLK tCLKH CLKA CSA W/RA MBA ENA EFA A0-A35 HIGH LOW LOW LOW tENS2 tENH tCLKL
tA
Next Word From FIFO2
Previous Word in FIFO2 Output Register
tSKEW1(1) CLKC FFC FIFO2 Full
tCLKH 1
tCLK
tCLKL 2 tWFF tENS2 tWFF tENH
MBC tENS2 ENC tDS C0-C17
Write To FIFO2
4665 drw24
tENH tDH tDS tDH
NOTES: 1. tSKEW1 is the minimum time between a rising CLKA edge and a rising CLKC edge for FFC to transition HIGH in the next CLKC cycle. If the time between the rising CLKA edge and rising CLKC edge is less than tSKEW1, then FFC may transition HIGH one CLKC cycle later than shown. 2. If Port C size is word or byte, FFC is set LOW by the last word or byte write of the long word, respectively (the word-size case is shown).
Figure 23. FFC Flag Timing and First Available Write when FIFO2 is Full (IDT Standard Mode)
CLKA tENS2 ENA tSKEW2 CLKB AEB
(1)
tENH
1
X1 Word in FIFO1
2 tPAE
(X1+1) Words in FIFO1
tPAE tENS2 tENH
RENB
4665 drw 25
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 = LOW, MBA = LOW), FIFO1 read (CSB = LOW, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO. 3. If Port B size is word or byte, AEB is set LOW by the last word or byte read from FIFO1, respectively.
Figure 24. Timing for AEB when FIFO1 is Almost-Empty (IDT Standard and FWFT Modes)
32
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKC tENS2 WENC tSKEW2 CLKA
(1)
tENH
1
2 tPAE tPAE
(X2+1) Words in FIFO2
AEA
X2 Words in FIFO2
tENS2 ENA
tENH
4665 drw 26
NOTES: 1. tSKEW2 is the minimum time between a rising CLKC edge and a rising CLKA edge for AEA to transition HIGH in the next CLKA cycle. If the time between the rising CLKC edge and rising CLKA edge is less than tSKEW2, then AEA may transition HIGH one CLKA cycle later than shown. 2. FIFO2 Write (MBC = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO. 3. If Port C size is word or byte, tSKEW2 is referenced to the rising CLKC edge that writes the last word or byte of the long word, respectively.
Figure 25. Timing for AEA when FIFO2 is Almost-Empty (IDT Standard and FWFT Modes)
tSKEW2 CLKA tENS2 ENA tPAF AFA CLKB tENS2 RENB
[D-(Y1+1)] Words in FIFO1
(1)
1 tENH
2
tPAF
(D-Y1) Words in FIFO1
tENH
4665 drw 27
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 CLKA cycle later than shown. 2. FIFO1 Write (CSA = LOW, W/RA = HIGH, MBA = LOW), FIFO1 read (CSB = LOW, MBB = LOW). Data in the FIFO1 output register has been read from the FIFO. 3. D = Maximum FIFO Depth = 2,048 for the IDT72V3656, 4,096 for the IDT72V3666, 8,192 for the IDT72V3676. 4. If Port B size is word or byte, tSKEW2 is referenced from the rising CLKB edge that reads the last word or byte of the long word, respectively.
Figure 26. Timing for AFA when FIFO1 is Almost-Full (IDT Standard and FWFT Modes)
tSKEW2 CLKC tENS2 WENC tPAF AFC CLKA tENS2 ENA tENH [D-(Y2+1)] Words in FIFO2 tENH
(1)
1
2
tPAF (D-Y2) Words in FIFO2
4665 drw 28
NOTES: 1. tSKEW2 is the minimum time between a rising CLKC edge and a rising CLKA edge for AFC to transition HIGH in the next CLKC cycle. If the time between the rising CLKC edge and rising CLKA edge is less than tSKEW2, then AFC may transition HIGH one CLKC cycle later than shown. 2. FIFO2 write (MBC = LOW), FIFO2 read (CSA = LOW, W/RA = LOW, MBA = LOW). Data in the FIFO2 output register has been read from the FIFO. 3. D = Maximum FIFO Depth = 2,048 for the IDT72V3656, 4,096 for the IDT72V3666, 8,192 for the IDT72V3676. 4. Port C size is word or byte, AFC is set LOW by the last word or byte write of the long word, respectively.
Figure 27. Timing for AFC when FIFO2 is Almost-Full (IDT Standard and FWFT Modes)
33
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
CLKA tENS1 CSA tENS1 W/RA tENS2 MBA
tENS2
COMMERCIAL TEMPERATURE RANGE
tENH tENH tENH tENH
tDS
ENA tDH A0-A35 CLKB tPMF MBF1 CSB MBB RENB tEN B0-B17 tMDV FIFO1 Output Register tPMR tDIS W1 (Remains valid in Mail1 Register after read) tENH tPMF W1
tENS2
4665 drw29 NOTE: 1. If Port B is configured for word size, data can be written to the Mail1 register using A0-A17 (A18-A35 are don't care inputs). In this first case B0-B17 will have valid data. If Port B is configured for byte size, data can be written to the Mail1 Register using A0-A8 (A9-A35 are don't care inputs). In this second case, B0-B8 will have valid data (B9-B17 will be indeterminate).
Figure 28. Timing for Mail1 Register and MBF1 Flag (IDT Standard and FWFT Modes)
CLKC tENS2 MBC tENS2 ENC C0-C17 CLKA tPMF MBF2 CSA W/RA MBA tENS2 ENA tEN A0-A35 tPMR tMDV FIFO2 Output Register tDIS W1 (Remains valid in Mail2 Register after read)
4665 drw30
tENH tENH tDH
tDS W1
tPMF
tENH
NOTE: 1. If Port C is configured for word size, data can be written to the Mail2 register using C0-C17. In this first case, A18-A35 will have valid data (A0-A17 will be indeterminate). If Port C is configured for byte size, data can be written to the Mail2 register using C0-C8 (C9-C17 are don't care inputs). In this second case, A18-A26 will have valid data (A0-A17 and A27-A35 will be indeterminate).
Figure 29. Timing for Mail2 Register and MBF2 Flag (IDT Standard and FWFT Modes)
34
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA CLKB
1 1
2 2
3 3
4 4 tENS2 tENH
RENB tRSTS RT1 tRTMS RTM tREF EFB B0-Bn Wx
(2)
tRSTH tRTMH
tREF
(2)
tA W1
4665 drw31
NOTES: 1. CSB = LOW 2. Retransmit setup is complete after EFB returns HIGH, only then can a read operation begin. 3. W1 = first word written to the FIFO1 after Master Reset on FIFO1. 4. No more than D-2 may be written to the FIFO1 between Reset of FIFO1 (Master or Partial) and Retransmit setup. Therefore, FFA will be LOW throughout the Retransmit setup procedure. D = 2,048, 4,096 and 8,192 for the IDT72V3656, IDT72V3666 and IDT72V3676 respectively.
Figure 30. Retransmit Timing for FIFO1 (IDT Standard Mode)
CLKC CLKA
1 1
2 2
3 3
4 4 tENS2 tENH
ENA tRSTS RT2 tRTMS RTM tREF EFA A0-An Wx
(2)
tRSTH tRTMH
(2)
tREF
tA W1
4665 drw32
NOTES: 1. CSA = LOW 2. Retransmit setup is complete after EFA returns HIGH, only then can a read operation begin. 3. W1 = first word written to the FIFO1 after Master Reset on FIFO2. 4. No more than D-2 may be written to the FIFO1 between Reset of FIFO2 (Master or Partial) and Retransmit setup. Therefore, FFC will be LOW throughout the Retransmit setup procedure. D = 2,048, 4,096 and 8,192 for the IDT72V3656, IDT72V3666 and IDT72V3676 respectively.
Figure 31. Retransmit Timing for FIFO2 (IDT Standard Mode)
35
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
CLKA CLKB
1 1
2 2
3 3
4 4
RENB RT1 RTM
LOW tRSTS tRTMS
tRSTH tRTMH
tREF ORB
(2)
tREF tA
(2)
B0-Bn
Wx
W1
4665 drw33
NOTES: 1. CSB = LOW 2. Retransmit setup is complete after ORB returns HIGH, only then can a read operation begin. 3. W1 = first word written to the FIFO1 after Master Reset on FIFO1. 4. No more than D-2 may be written to the FIFO1 between Reset of FIFO1 (Master or Partial) and Retransmit setup. Therefore, IRA will be LOW throughout the Retransmit setup procedure. D = 2,049, 4,097 and 8,193 for the IDT72V3656, IDT72V3666 and IDT72V3676 respectively.
Figure 32. Retransmit Timing for FIFO1 (FWFT Mode)
CLKC CLKA
1 1 LOW tRSTS tRTMS
2 2
3 3
4 4
ENA RT2 RTM
tRSTH tRTMH
(2)
tREF ORA
tREF tA
(2)
A0-An
Wx
W1
4665 drw34
NOTES: 1. CSA = LOW 2. Retransmit setup is complete after ORA returns HIGH, only then can a read operation begin. 3. W1 = first word written to the FIFO2 after Master Reset on FIFO2. 4. No more than D-2 may be written to the FIFO2 between Reset of FIFO2 (Master or Partial) and Retransmit setup. Therefore, IRC will be LOW throughout the Retransmit setup procedure. D = 2,049, 4,097 and 8,193 for the IDT72V3656, IDT72V3666 and IDT72V3676 respectively.
Figure 33. Retransmit Timing for FIFO2 (FWFT Mode)
36
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
tCLKH CLKA LOOP CSA W/RA
tCLK tCLKL
MBA tENS2 ENA tMDV tEN A0-A35 tA Wn-1(1) Write to FIFO 1 Wn(1) Write to FIFO 1 tA No Operation Wn+1
4665 drw35
tENH
tENS2
tENH
tENS2
tENH tDIS
NOTES: 1. Data is read from FIFO2 and written into FIFO1 & placed on Port A simultaneously. The first data word written into FIFO1 is the Previous Data Word (Wn-1) 2. All FIFO status flags operate as normal, based on the contents of respective FIFO's. 3. Loopback is available in both Standard IDT and FWFT modes. The diagram above is for both.
Figure 34. Loopback Operation (FIFO2 data transfer to FIFO1 and Port A)
tCLKH CLKA LOOP CSA W/RA
tCLK tCLKL
MBA tENS2 ENA tMDV
(4) WRITE
tENH
tENS2
tENH
tENS2 No Operation Wn+1
tENH tDIS
tEN
tA Wn-1(1) Write to FIFO 1 Wn(1) Write to FIFO 1
tA
to FIFO 1 A0-A35 HIGH-Z
4665 drw36
NOTES: 1. Data is read from FIFO2 and written into FIFO1 only. The data from FIFO2 is NOT placed on Port A. Port A is held in the high impedance state. 2. All FIFO status flags operate as normal, based on the contents of respective FIFO's. 3. Loopback is available in both Standard IDT and FWFT modes. The diagram above is for both. 4. Write operations to FIFO1 cannot be accessed via Port A.
Figure 35. Loopback Operation (FIFO2 data transfer to FIFO1)
37
IDT72V3656/72V3666/72V3676 3.3V CMOS TRIPLE BUS SyncFIFOTM WITH BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2, 8,192 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PARAMETER MEASUREMENT INFORMATION
3.3V
330 From Output Under Test 30 pF 510
(1)
PROPAGATION DELAY LOAD CIRCUIT 3V Timing Input tS Data, Enable Input 1.5V VOLTAGE WAVEFORMS SETUP AND HOLD TIMES Output Enable tPLZ Low-Level Output 3V 1.5V 1.5V tPZL 1.5V tPZH 1.5V OV VOLTAGE WAVEFORMS PROPAGATION DELAY TIMES
4665 drw 37
1.5V GND th 3V 1.5V GND
High-Level Input
3V 1.5V tW 3V 1.5V GND
Low-Level Input
1.5V VOLTAGE WAVEFORMS PULSE DURATIONS
1.5V GND
GND 3V VOL VOH In-Phase Output Input 3V 1.5V tPD 1.5V 1.5V GND tPD VOH 1.5V VOL
High-Level Output
tPHZ VOLTAGE WAVEFORMS ENABLE AND DISABLE TIMES
NOTE: 1. Includes probe and jig capacitance.
Figure 36. Load Circuit and Voltage Waveforms
38
ORDERING INFORMATION
IDT XXXXXX Device Type X Power XX Speed XX Package X Process/ Temperature Range BLANK PF 10 15 L 72V3656 72V3666 72V3676
NOTE: 1. Industrial temperature range is available by special order.
Commercial (0C to +70C) Thin Quad Flat Pack (TQFP, PK128-1) Commercial Only Low Power 2,048 x 36 x 2 3.3V Triple Bus SyncFIFO with Bus-Matching 4,096 x 36 x 2 3.3V Triple Bus SyncFIFO with Bus-Matching 8,192 x 36 x 2 3.3V Triple Bus SyncFIFO with Bus-Matching
4665 drw38
Clock Cycle Time (tCLK) Speed in Nanoseconds
DATASHEET DOCUMENT HISTORY
6/14/2000 9/26/2000 12/22/2000 03/21/2001 pgs.1, 2, 3, 5, 6, 8, 9, 10, 11, 13, 14, 16, 21, 22, 24 through 34, 37 and 39. pgs. 7, 9, 10 and 39. pgs. 5, 6, 13 and 22. pgs. 7 and 8. CORPORATE HEADQUARTERS 2975 Stender Way Santa Clara, CA 95054 for SALES: 800-345-7015 or 408-727-6116 fax: 408-492-8674 www.idt.com for TECH SUPPORT: 408-330-1753 e-mail: FIFOhelp@idt.com PF Pkg: www.idt.com/docs/PSC4045.pdf
*To search for sales office near you, please click the sales button found on our home page or dial the 800# above and press 2. The SyncFIFO is a trademark and the IDT logo is a registered trademark of Integrated Device Technology, Inc.
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