IDT72801 IDT72811 IDT72821 IDT72831 IDT72841 IDT72851 DUAL CMOS SyncFIFO™ DUAL 256 x 9, DUAL 512 x 9, DUAL 1,024 x 9, DUAL 2,048 x 9, DUAL 4,096 x 9, DUAL 8,192 x 9 FEATURES: • • • • • • • • • • • • • • • The IDT72801 is equivalent to two IDT72201 256 x 9 FIFOs The IDT72811 is equivalent to two IDT72211 512 x 9 FIFOs The IDT72821 is equivalent to two IDT72221 1,024 x 9 FIFOs The IDT72831 is equivalent to two IDT72231 2,048 x 9 FIFOs The IDT72841 is equivalent to two IDT72241 4,096 x 9 FIFOs The IDT72851 is equivalent to two IDT72251 8,192 x 9 FIFOs Offers optimal combination of large capacity, high speed, design flexibility and small footprint Ideal for prioritization, bidirectional, and width expansion applications 10 ns read/write cycle time for the IDT72801/72811/72821/72831/ 72841 (excluding the IDT72851) 15 ns read/write cycle time for the IDT72851 Separate control lines and data lines for each FIFO Separate Empty, Full, Programmable Almost-Empty and AlmostFull flags for each FIFO Enable puts output data lines in high-impedance state Space-saving 64-pin Thin Quad Flat Pack (TQFP) and Slim Thin Quad Flatpack (STQFP) Industrial temperature range (–40°°C to +85°°C) is available DESCRIPTION: The IDT72801/72811/72821/72831/72841/72851 are dual synchronous (clocked) FIFOs. The device is functionally equivalent to two IDT72201/72211/ 72221/72231/72241/72251 FIFOs in a single package with all associated control, data, and flag lines assigned to separate pins. Each of the two FIFOs (designated FIFO A and FIFO B) contained in the IDT72801/72811/72821/72831/72841/72851 has a 9-bit input data port (DA0 - DA8, DB0 - DB8) and a 9-bit output data port (QA0 - QA8, QB0 - QB8). Each input port is controlled by a free-running clock (WCLKA, WCLKB), and two Write Enable pins (WENA1, WENA2, WENB1, WENB2). Data is written into each of the two arrays on every rising clock edge of the Write Clock (WCLKA, WCLKB) when the appropriate write enable pins are asserted. The output port of each FIFO bank is controlled by its associated clock pin (RCLKA, RCLKB) and two Read Enable pins (RENA1, RENA2, RENB1, RENB2). The Read Clock can be tied to the Write Clock for single clock operation or the two clocks can run asynchronous of one another for dual clock operation. An Output Enable pin (OEA, OEB) is provided on the read port of each FIFO for three-state output control. Each of the two FIFOs has two fixed flags, Empty (EFA, EFB) and Full (FFA, FFB). Two programmable flags, Almost-Empty (PAEA, PAEB) and Almost-Full (PAFA, PAFB), are provided for each FIFO bank to improve memory utilization. If not programmed, the programmable flags default to empty+7 for PAEA and PAEB, and full-7 for PAFA and PAFB. The IDT72801/72811/72821/72831/72841/72851 architecture lends itself to many flexible configurations such as: • 2-level priority data buffering • Bidirectional operation • Width expansion • Depth expansion These FIFOs is fabricated using IDT's high-performance submicron CMOS technology. FUNCTIONAL BLOCK DIAGRAM WCLKA WENA1 WENA2 EFA PAEA PAFA LDA FFA DA0 - DA8 INPUT REGISTER WRITE CONTROL LOGIC RAM ARRAY 256 x 9, 512 x 9, 1024 x 9, 2048 x 9, 4096 x 9, 8192 x 9 WRITE POINTER WCLKB WENB1 DB0 - DB8 OFFSET REGISTER INPUT REGISTER FLAG LOGIC WRITE CONTROL LOGIC READ POINTER WRITE POINTER OFFSET REGISTER FLAG LOGIC RAM ARRAY 256 x 9, 512 x 9, 1024 x 9, 2048 x 9, 4096 x 9, 8192 x 9 READ CONTROL LOGIC EFB PAEB PAFB FFB READ POINTER READ CONTROL LOGIC OUTPUT REGISTER OUTPUT REGISTER RESET LOGIC RSA LDB WENB2 RESET LOGIC OEA QA0 - QA8 RCLKA RENA1 RENA2 RSB OEB QB0 - QB8 RCLKB RENB1 RENB2 3034 drw 01 SyncFIFO is a trademark and the IDT logo is a registered trademark of Integrated Device Technology, Inc. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGE 2001 Integrated Device Technology, Inc. APRIL 2001 DSC-3034/1 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 QA0 FFA EFA OEA RENA2 RCLKA RENA1 GND QB8 QB7 QB6 QB5 QB4 QB3 QB2 QB1 PIN CONFIGURATION 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 QB0 FFB EFB OEB RENB2 RCLKB RENB1 GND VCC PAEB PAFB DB0 DB1 DB2 DB3 DB4 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 DA5 DA4 DA3 DA2 DA1 DA0 PAFA PAEA WENB2/LDB WCLKB WENB1 RSB DB8 DB7 DB6 DB5 QA1 QA2 QA3 QA4 QA5 QA6 QA7 QA8 VCC WENA2/LDA WCLKA WENA1 RSA DA8 DA7 DA6 TQFP (PN64-1, order code: PF) STQFP (PP64-1, order code: TF) TOP VIEW 2 3034 drw 02 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 PIN DESCRIPTIONS The IDT72801/72811/72821/72831/72841/72851s two FIFOs, referred to as FIFO A and FIFO B, are identical in every respect. The following description defines the input and output signals for FIFO A. The corresponding signal names for FIFO B are provided in parentheses. Symbol DA0-DA8 Name A Data Inputs I/O I DB0-DB8 RSA, RSB B Data Inputs Reset I I 9-bit data inputs to RAM array B. When RSA (RSB) is set LOW, the associated internal read and write pointers of array A (B) are set to the first location; FFA (FFB) and PAFA (PAFB) go HIGH, and PAEA (PAEB) and EFA (EFB) go LOW. After power-up, a reset of both FIFOs A and B is required before an initial Write. WCLKA WCLKB Write Clock I WENA1 WENB1 Write Enable 1 I Data is written into the FIFO A (B) on a LOW-to-HIGH transition of WCLKA (WCLKB) when the write enable(s) are asserted. If FIFO A (B) is configured to have programmable flags, WENA1 (WENB1) is the only Write Enable pin that can be used. When WENA1 (WENB1) is LOW, data A (B) is written into the FIFO on every LOW-to-HIGH transition WCLKA (WCLKB). If the FIFO is configured to have two write enables, WENA1 (WENB1) must be LOW and WENA2 (WENB2) must be HIGH to write data into the FIFO. Data will not be written into the FIFO if FFA (FFB) is LOW. WENA2/LDA WENB2/LDB Write Enable 2/ Load I QA0-QA8 A Data Outputs O QB0-QB8 RCLKA RCLKB B Data Outputs Read Clock O I 9-bit data outputs from RAM array B. Data is read from FIFO A (B) on a LOW-to-HIGH transition of RCLKA (RCLKB) when RENA1 (RENB1) and RENA2 (RENB2) are asserted. RENA1 RENB1 Read Enable 1 I RENA2 RENB2 Read Enable 2 I When RENA1 (RENB1) and RENA2 (RENB2) are LOW, data is read from FIFO A (B) on every LOW-to-HIGH transition of RCLKA (RCLKB). Data will not be read from Array A (B) if EFA (EFB) is LOW. When RENA1 (RENB1) and RENA2 (RENB2) are LOW, data is read from the FIFO A (B) on every LOW-to-HIGH transition of RCLKA (RCLKB). Data will not be read from array A (B) if the EFA (EFB) is LOW. OEA OEB Output Enable I EFA EFB Empty Flag O PAEA PAEB Programmable Almost-Empty Flag Programmable Almost-Full Flag O FFA FFB Full Flag O VCC GND Power Ground PAFA PAFB O Description 9-bit data inputs to RAM array A. FIFO A (B) is configured at reset to have either two write enables or programmable flags. If LDA (LDB) is HIGH at reset, this pin operates as a second write enable. If WENA2/LDA (WENB2/LDB) is LOW at reset this pin operates as a control to load and read the programmable flag offsets for its respective array. If the FIFO is configured to have two write enables, WENA1 ( WENB1) must be LOW and WENA2 (WENB2) must be HIGH to write data into FIFO A (B). Data will not be written into FIFO A (B) if FFA (FFB) is LOW. If the FIFO is configured to have programmable flags, LDA (LDB) is held LOW to write or read the programmable flag offsets. 9-bit data outputs from RAM array A. When OEA (OEB) is LOW, outputs DA0-DA8 (DB0-DB8) are active. If OEA (OEB) is HIGH, the outputs DA0-DA8 (DB0-DB8) will be in a high-impedance state. When EFA (EFB) is LOW, FIFO A (B) is empty and further data reads from the output are inhibited. When EFA (EFB) is HIGH, FIFO A (B) is not empty. EFA (EFB) is synchronized to RCLKA (RCLKB). When PAEA (PAEB) is LOW, FIFO A (B) is almost-empty based on the offset programmed into the appropriate offset register. The default offset at reset is Empty+7. PAEA (PAEB) is synchronized to RCLKA (RCLKB). When PAFA (PAFB) is LOW, FIFO A (B) is almost-full based on the offset programmed into the appropriate offset register. The default offset at reset is Full-7. PAFA (PAFB) is synchronized to WCLKA (WCLKB). When FFA (FFB) is LOW, FIFO A (B) is full and further data writes into the input are inhibited. When FFA (FFB) is HIGH, FIFO A (B) is not full. FFA (FFB) is synchronized to WCLKA (WCLKB). +5V power supply pin. 0V ground pin. 3 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 ABSOLUTE MAXIMUM RATINGS Symbol VTERM TSTG IOUT Rating Com'l & Ind'l Terminal Voltage with Respect to GND StorageTemperature DC Output Current –0.5 to +7.0 –55 to +125 –50 to +50 RECOMMENDEDOPERATINGCONDITIONS Unit Symbol V VCC °C mA GND VIH NOTE: 1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. Parameter Supply Voltage (Com'l & Ind'l) Supply Voltage (Com'l & Ind'l) Input High Voltage (Com'l & Ind'l) Input Low Voltage (Com'l & Ind'l) Operating Temperature Commercial Operating Temperature Industrial VIL TA TA Min. Typ. Max. Unit 4.5 5.0 5.5 V 0 0 0 V 2.0 — — V — 0 — — 0.8 V 70 °C –40 — 85 °C DC ELECTRICAL CHARACTERISTICS (Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C; Industrial: VCC = 5V ± 10%, TA = –40°C to +85°C) IDT72801 IDT72811 IDT72821 IDT72831 IDT72841 Commercial and Industrial(1) tCLK = 10, 15, 25 ns Symbol Parameter Min. Typ. Max. Input Leakage Current (Any Input) –1 — ILO(3) Output Leakage Current –10 VOH Output Logic “1” Voltage, IOH = –2 mA VOL IDT72851 Commercial and Industrial(1) tCLK = 10, 15, 25 ns Min. Typ. Max. Unit 1 –1 — 1 µA — 10 –10 — 10 µA 2.4 — — 2.4 — — V Output Logic “0” Voltage, IOL = 8 mA — — 0.4 — — 0.4 V ICC1(4,5,6,8) Active Power Supply Current (both FIFOs) — — 60 — — 80 mA ICC2(4,7,8) Standby Current — — 10 — — 10 mA ILI (2) NOTES: 1. Industrial temperature range product for 15ns and 25ns speed grade are available as a standard device. 2. Measurements with 0.4 ≤ VIN ≤ VCC. 3. OE ≥ VIH, 0.4 ≤ VOUT ≤ VCC. 4. Tested with outputs open (IOUT = 0). 5. RCLK and WCLK toggle at 20 MHz and data inputs switch at 10 MHz. 6. Typical ICC1 = 2*[1.7 + 0.7*fS + 0.02*CL*fS] (in mA). These equations are valid under the following conditions: VCC = 5V, TA = 25°°C, fS = WCLK frequency = RCLK frequency (in MHz, using TTL levels), data switching at fS/2, CL = capacitive load (in pF). 7. All Inputs = VCC - 0.2V or GND + 0.2V, except RCLK and WCLK, which toggle at 20 MHz. 8. ICC1 and ICC2 parameters are improved as compared to previous data sheets. CAPACITANCE (TA = +25°C, f = 1.0MHz) Symbol (2) CIN COUT (1,2) Parameter Conditions Max. Unit Input Capacitance VIN = 0V 10 pF Output Capacitance VOUT = 0V 10 pF NOTE: 1. With output deselected (OEA, OEB ≥ VIH). 2. Characterized values, not currently tested. 4 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 AC ELECTRICAL CHARACTERISTICS (Commercial: VCC = 5V ± 10%, TA = 0°C to +70°C; Industrial: VCC = 5V ± 10%, TA = –40°C to +85°C) Com'l & Ind'l (1) Commercial IDT72801L10 IDT72811L10 IDT72821L10 IDT72831L10 IDT72841L10 IDT72851L10 IDT72801L15 IDT72811L15 IDT72821L15 IDT72831L15 IDT72841L15 IDT72851L15 IDT72801L25 IDT72811L25 IDT72821L25 IDT72831L25 IDT72841L25 IDT72851L25 Symbol Parameter Min Max. Min Max. Min Max. Unit fS Clock Cycle Frequency — 100 — 66.7 — 40 MHz tA Data Access Time 2 6.5 2 10 2 15 ns tCLK Clock Cycle Time 10 — 15 — 25 — ns tCLKH Clock High Time 4.5 — 6 — 10 — ns tCLKL Clock Low Time 4.5 — 6 — 10 — ns tDS Data Setup Time 3 — 4 — 6 — ns tDH Data Hold Time 0.5 — 1 — 1 — ns tENS Enable Setup Time 3 — 4 — 6 — ns tENH Enable Hold Time 0.5 — 1 — 1 — ns (2) tRS Reset Pulse Width 10 — 15 — 15 — ns tRSS Reset Setup Time 8 — 10 — 15 — ns tRSR Reset Recovery Time 8 — 10 — 15 — ns tRSF Reset to Flag Time and Output Time — 10 — 15 — 25 ns 0 — 0 — 0 — ns 3 6 3 8 3 13 ns ns tOLZ Output Enable to Output in Low-Z(3) tOE Output Enable to Output Valid tOHZ Output Enable to Output in High-Z(3) 3 6 3 8 3 13 tWFF Write Clock to Full Flag — 6.5 — 10 — 15 ns tREF Read Clock to Empty Flag — 6.5 — 10 — 15 ns tPAF Write Clock to Programmable Almost-Full Flag — 6.5 — 10 — 15 ns tPAE Read Clock to Programmable Almost-Empty Flag — 6.5 — 10 — 15 ns tSKEW1 Skew Time Between Read Clock and Write Clock for Empty Flag and Full Flag 5 — 6 — 10 — ns tSKEW2 Skew Time Between Read Clock and Write Clock for Programmable Almost-Empty Flag and Programmable Almost-Full Flag 14 — 15 — 18 — ns NOTES: 1. Industrial temperature range product for 15ns and 25ns speed grade are available as a standard device. 2. Pulse widths less than minimum values are not allowed. 3. Values guaranteed by design, not currently tested. 5V 1.1K D.U.T. AC TEST CONDITIONS In Pulse Levels GND to 3.0V Input Rise/Fall Times 3ns Input Timing Reference Levels 1.5V Output Reference Levels 1.5V Output Load 680Ω 30pF* 3034 drw 03 or equivalent circuit See Figure 1 Figure 1. Output Load *Includes jig and scope capacitances. 5 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 SIGNAL DESCRIPTIONS When either of the two Read Enable RENA1, RENA2 (RENB1, RENB2) associated with FIFO A (B) is HIGH, the output register holds the previous data and no new data is allowed to be loaded into the register. When all the data has been read from FIFO A (B), the Empty Flag EFA (EFB) will go LOW, inhibiting further read operations. Once a valid write operation has been accomplished, EFA (EFB) will go HIGH after tREF and a valid read can begin. The Read Enables RENA1, RENA2(RENB1, RENB2) are ignored when FIFO A (B) is empty. FIFO A and FIFO B are identical in every respect. The following description explains the interaction of input and output signals for FIFO A. The corresponding signal names for FIFO B are provided in parentheses. INPUTS: Data In (DA0 – DA8, DB0 – DB8) —DA0 - DA8 are the nine data inputs for memory array A. DB0 - DB8 are the nine data inputs for memory array B. Output Enable (OEA, OEB) — When Output Enable OEA (OEB) is enabled (LOW), the parallel output buffers of FIFO A (B) receive data from their respective output register. When Output Enable OEA (OEB) is disabled (HIGH), the QA (QB) output data bus is in a high-impedance state. CONTROLS: Reset (RSA, RSB) — Reset of FIFO A (B) is accomplished whenever RSA (RSB) input is taken to a LOW state. During Reset, the internal read and write pointers associated with the FIFO are set to the first location. A Reset is required after power-up before a write operation can take place. The Full Flag FFA (FFB) and Programmable Almost-Full flag PAFA (PAFB) will be reset to HIGH after tRSF. The Empty Flag EFA (EFB) and Programmable Almost-Empty flag PAEA (PAEB) will be reset to LOW after tRSF. During Reset, the output register is initialized to all zeros and the offset registers are initialized to their default values. Write Enable 2/Load (WENA2/LDA, WENB2/LDB) — This is a dualpurpose pin. FIFO A (B) is configured at Reset to have programmable flags or to have two write enables, which allows depth expansion. If WENA2/LDA (WENB2/LDB) is set HIGH at Reset RSA = LOW (RSB = LOW), this pin operates as a second write enable pin. If FIFO A (B) is configured to have two write enables, when Write Enable 1 WENA1 (WENB1) is LOW and WENA2/LDA (WENB2/LDB) is HIGH, data can be loaded into the input register and RAM array on the LOW-to-HIGH transition of every Write Clock WCLKA (WCLKB). Data is stored in the array sequentially and independently of any ongoing read operation. In this configuration, when WENA1 (WENB1) is HIGH and/or WENA2/LDA (WENB2/LDB) is LOW, the input register of Array A holds the previous data and no new data is allowed to be loaded into the register. To prevent data overflow, the Full Flag FFA (FFB) will go LOW, inhibiting further write operations. Upon the completion of a valid read cycle, FFA (FFB) will go HIGH after tWFF, allowing a valid write to begin. WENA1, (WENB1) and WENA2/LDA (WENB2/LDB) are ignored when the FIFO is full. FIFO A (B) is configured to have programmable flags when the WENA2/ LDA (WENB2/LDB) is set LOW at Reset RSA = LOW (RSB = LOW). Each FIFO contains four 8-bit offset registers which can be loaded with data on the inputs, or read on the outputs. See Figure 3 for details of the size of the registers and the default values. If FIFO A (B) is configured to have programmable flags, when the WENA1 (WENB1) and WENA2/LDA (WENB2/LDB) are set LOW, data on the DA (DB) inputs are written into the Empty (Least Significant Bit) Offset register on the first LOW-to-HIGH transition of the WCLKA (WCLKB). Data are written into the Empty (Most Significant Bit) Offset register on the second LOW-to-HIGH transition of WCLKA (WCLKB), into the Full (Least Significant Bit) Offset register on the third transition, and into the Full (Most Significant Bit) Offset register on the fourth transition. The fifth transition of WCLKA (WCLKB) again writes to the Empty (Least Significant Bit) Offset register. However, writing all offset registers does not have to occur at one time. One or two offset registers can be written and then by bringing LDA (LDB) HIGH, FIFO A (B) is returned to normal read/write operation. When LDA (LDB) is set LOW, and WENA1 (WENB1) is LOW, the next offset register in sequence is written. The contents of the offset registers can be read on the QA (QB) outputs when WENA2/LDA (WENB2/LDB) is set LOW and both Read Enables RENA1, RENA2 (RENB1, RENB2) are set LOW. Data can be read on the LOW-to-HIGH transition of the Read Clock RCLKA (RCLKB). Write Clock (WCLKA, WCLKB) — A write cycle to Array A (B) is initiated on the LOW-to-HIGH transition of WCLKA (WCLKB). Data setup and hold times must be met with respect to the LOW-to-HIGH transition of WCLKA (WCLKB). The Full Flag FFA (FFB) and Programmable Almost-Full flag PAFA (PAFB) are synchronized with respect to the LOW-to-HIGH transition of the Write Clock WCLKA (WCLKB). The Write and Read Clocks can be asynchronous or coincident. Write Enable 1 (WENA1, WENB1) — If FIFO A (B) is configured for programmable flags, WENA1 (WENB1) is the only enable control pin. In this configuration, when WENA1 (WENB1) is LOW, data can be loaded into the input register of RAM Array A (B) on the LOW-to-HIGH transition of every Write Clock WCLKA (WCLKB). Data is stored in Array A (B) sequentially and independently of any ongoing read operation. In this configuration, when WENA1 (WENB1) is HIGH, the input register holds the previous data and no new data is allowed to be loaded into the register. If the FIFO is configured to have two write enables, which allows for depth expansion. See Write Enable 2 paragraph below for operation in this configuration. To prevent data overflow, FFA (FFB) will go LOW, inhibiting further write operations. Upon the completion of a valid read cycle, the FFA (FFB) will go HIGH after tWFF, allowing a valid write to begin. WENA1 (WENB1) is ignored when FIFO A (B) is full. Read Clock (RCLKA, RCLKB) — Data can be read from Array A (B) on the LOW-to-HIGH transition of RCLKA (RCLKB). The Empty Flag EFA (EFB) and Programmable Almost-Empty Flag PAEA (PAEB) are synchronized with respect to the LOW-to-HIGH transition of RCLKA (RCLKB). The Write and Read Clocks can be asynchronous or coincident. Read Enables (RENA1, RENA2, RENB1, RENB2) — When both Read Enables RENA1, RENA2 (RENB1, RENB2) are LOW, data is read from Array A (B) to the output register on the LOW-to-HIGH transition of the Read Clock RCLKA (RCLKB). 6 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 LDA WENA1 WCLKA OPERATION ON FIFO A LDB WENB1 WCLKB OPERATION ON FIFO B 0 0 A read and write should not be performed simultaneously to the offset registers. Empty Offset (LSB) OUTPUTS: Empty Offset (MSB) Full Flag (FFA, FFB) — FFA (FFB) will go LOW, inhibiting further write operations, when Array A (B) is full. If no reads are performed after reset, FFA (FFB) will go LOW after 256 writes to the IDT72801's FIFO A (B); 512 writes to the IDT72811's FIFO A (B); 1,024 writes to the IDT72821's FIFO A (B); 2,048 writes to the IDT72831's FIFO A (B); 4,096 writes to the IDT72841's FIFO A (B); or 8,192 writes to the IDT72851's FIFO A (B). FFA (FFB) is synchronized with respect to the LOW-to-HIGH transition of the Write Clock WCLKA (WCLKB). Full Offset (LSB) Full Offset (MSB) 0 1 No Operation 1 0 Write Into FIFO 1 1 No Operation Empty Flag (EFA, EFB) — EFA (EFB) will go LOW, inhibiting further read operations, when the read pointer is equal to the write pointer, indicating that Array A (B) is empty. EFA (EFB) is synchronized with respect to the LOW-to-HIGH transition of the Read Clock RCLKA (RCLKB). NOTE: 1. For the purposes of this table, WENA1 and WENB1 = VIH. 2. The same selection sequence applies to reading from the registers. RENA1 and RENA2 (RENB1 and RENB2) are enabled and read is performed on the LOW-toHIGH transition of RCLKA (RCLKB). Figure 2. Writing to Offset Registers for FIFOs A and B 72801 - DUAL 256 x 9 8 0 8 0 7 Empty Offset (LSB) Default Value 007H Default Value 007H Default Value 007H 0 7 0 8 0 1 8 8 8 8 (MSB) 0 0 0 8 8 0 7 Full Offset (LSB) Reg. Default Value 007H Default Value 007H 1 0 8 0 1 (MSB) (MSB) 0 0 72841 - DUAL 4,096 x 9 0 0 1 Full Offset (LSB) 8 72851 - DUAL 8,192 x 9 0 7 8 0 7 Empty Offset (LSB) Reg. Empty Offset (LSB) Empty Offset (LSB) Default Value 007H Default Value 007H Default Value 007H 0 2 3 8 0 8 4 0 (MSB) (MSB) (MSB) 0 0 0 7 0 8 Full Offset (LSB) Reg. Default Value 007H 8 0 (MSB) 7 72831 - DUAL 2,048 x 9 7 8 0 7 Empty Offset (LSB) Full Offset (LSB) Reg. Default Value 007H 8 8 Empty Offset (LSB) Reg. 8 8 72821 - DUAL 1,024 x 9 72811 - DUAL 512 x 9 7 0 2 0 7 8 0 7 Full Offset (LSB) Full Offset (LSB) Default Value 007H Default Value 007H 3 8 0 8 4 0 (MSB) (MSB) (MSB) 0 0 0 3034 drw 04 Figure 3. Offset Register Formats and Default Values for the A and B FIFOs 7 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 Programmable Almost–Full Flag (PAFA, PAFB) — PAFA (PAFB) will go LOW when the amount of data in Array A (B) reaches the almost-full condition. If no reads are performed after Reset, PAFA (PAFB) will go LOW after (256-m) writes to the IDT72801's FIFO A (B); (512-m) writes to the IDT72811's FIFO A (B); (1,024-m) writes to the IDT72821's FIFO A (B); (2,048-m) writes to the IDT72831's FIFO A (B); (4,096-m) writes to the IDT72841's FIFO A (B); or (8,192-m) writes to the IDT72851's FIFO A (B). FFA (FFB) is synchronized with respect to the LOW-to-HIGH transition of the Write Clock WCLKA (WCLKB). The offset “m” is defined in the Full Offset registers. If there is no Full offset specified, PAFA (PAFB) will go LOW at Full-7 words. PAFA (PAFB) is synchronized with respect to the LOW-to-HIGH transition of WCLKA (WCLKB). Programmable Almost–Empty Flag (PAEA, PAEB) — PAEA (PAEB) will go LOW when the read pointer is "n+1" locations less than the write pointer. The offset "n" is defined in the Empty Offset registers. If no reads are performed after Reset, PAEA (PAEB) will go HIGH after "n+1" writes to FIFO A (B). If there is no Empty offset specified, PAEA (PAEB) will go LOW at Empty+7 words. PAEA (PAEB) is synchronized with respect to the LOW-to-HIGH transition of the Read Clock RCLKA (RCLKB). Data Outputs (QA0 – QA8, QB0 – QB8 ) — QA0 - QA8 are the nine data outputs for memory array A, QB0 - QB8 are the nine data outputs for memory array B. TABLE 1: STATUS FLAGS FOR A AND B FIFOS NUMBER OF WORDS IN ARRAY A NUMBER OF WORDS IN ARRAY B 72801 0 1 to n(1) (n+1) to (256-(m+1)) (256-m)(2) to 255 256 72811 0 1 to n(1) (n+1) to (512-(m+1)) (512-m)(2) to 511 512 72821 0 1 to n(1) (n+1) to (1,024-(m+1)) (1,024-m)(2) to 1,023 1,024 NUMBER OF WORDS IN ARRAY A NUMBER OF WORDS IN ARRAY B 72831 0 1 to n(1) (n+1) to (2,048-(m+1)) (2,048-m)(2) to 2,047 2,048 72841 0 1 to n(1) (n+1) to (4,096-(m+1)) (4,096-m)(2) to 4,095 4,096 72851 0 1 to n(1) (n+1) to (8,192-(m+1)) (8,192-m)(2) to 8,191 8,192 NOTES: 1. n = Empty Offset (n = 7 default value) 2. m = Full Offset (m = 7 default value) 8 FFA PAFA PAEA EFA FFB PAFB PAEB EFB H H H L L L L H H H FFA PAFA PAEA EFA FFB PAFB PAEB EFB H H H L L L L H H H H H H H L H H H H L L H H H H L H H H H Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 tRS RSA (RSB) tRSS tRSR tRSS tRSR tRSS tRSR RENA1, RENA2 (RENB1, RENB2) WENA1 (WENB1) WENA2/LDA(1) (WENB2/LDB) tRSF EFA, PAEA (EFB, PAEB) tRSF FFA, PAFA (FFB, PAFB) tRSF (2) OEA (OEB) = 1 QA0 - QA8 (QB0 - QB8) OEA (OEB) = 0 3034 drw 05 NOTES: 1. Holding WENA2/LDA (WENB2/LDB) HIGH during reset will make the pin act as a second write enable pin. Holding WENA2/LDA (WENB2/LDB) LOW during reset will make the pin act as a load enable for the programmable flag offset registers. 2. After reset, QA0 - QA8 (QB0 - QB8) will be LOW if OEA (OEB) = 0 and tri-state if OEA (OEB) = 1. 3. The clocks RCLKA, WCLKA (RCLKB, WCLKB) can be free-running during reset. Figure 4. Reset Timing tCLK tCLKH tCLKL WCLKA (WCLKB) tDS tDH DA0 - DA8 (DB0 - DB8) DATA IN VALID tENS WENA1 (WENB1) tENH NO OPERATION tENS tENH WENA2 (WENB2) (If Applicable) NO OPERATION tWFF tWFF FFA (FFB) tSKEW1(1) RCLKA (RCLKB) RENA1, RENA2 (RENB1, RENB2) 3034 drw 06 NOTE: 1. tSKEW1 is the minimum time between a rising RCLKA (RCLKB) edge and a rising WCLKA (WCLKB) edge for FFA (FFB) to change during the current clock cycle. If the time between the rising edge of RCLKA (RCLKB) and the rising edge of WCLKA (WCLKB) is less than tSKEW1, then FFA (FFB) may not change state until the next WCLKA (WCLKB) edge. Figure 5. Write Cycle Timing 9 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 tCLK tCLKH tCLKL RCLKA (RCLKB) tENS tENH RENA1, RENA2 (RENB1, RENB2) NO OPERATION tREF tREF EFA (EFB) tA QA0 - QA8 (QB0 - QB8) VALID DATA tOLZ tOHZ tOE OEA (OEB) tSKEW1(1) WCLKA (WCLKB) WENA1 (WENB1) WENA2 (WENB2) 3034 drw 07 NOTE: 1. tSKEW1 is the minimum time between a rising WCLKA (WCLKB) edge and a rising RCLKA (RCLKB) edge for EFA (EFB) to change during the current clock cycle. If the time between the rising edge of RCLKA (RCLKB) and the rising edge of WCLKA (WCLKB) is less than tSKEW1, then EFA (EFB) may not change state until the next RCLKA (RCLKB) Figure 6. Read Cycle Timing WCLKA (WCLKB) tDS DA0 - DA8 (DB0 - DB8) D1 D2 D3 D0 (First Valid Write) tENS WENA1 (WENB1) tENS WENA2 (WENB2) (If Applicable) tSKEW1 tFRL (1) RCLKA (RCLKB) tREF EFA (EFB) tENS RENA1, RENA2 (RENB1, RENB2) tA tA QA0 - QA8 (QB0 - QB8) D0 D1 tOLZ tOE OEA (OEB) NOTE: 1. When tSKEW1 ≥ minimum specification, tFRL = tCLK + tSKEW1 When tSKEW1 < minimum specification, tFRL = 2tCLK + tSKEW1V or tCLK + tSKEW1 The Latency Timings apply only at the Empty Boundary (EFA, EFB = LOW). 3034 drw 08 Figure 7. First Data Word Latency Timing 10 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 NO WRITE NO WRITE WCLKA (WCLKB) tSKEW1 tDS NO WRITE tSKEW1 tDH DA0 - DA8 (DB0 - DB8) tWFF tWFF tWFF FFA (FFB) (1) tENS tENH tENS tENS tENH tENS WENA1 (WENB1) (1) WENA2 (WENB2) (If Applicable) RCLKA (RCLKB) tENH tENH tENS tENS RENA1 (RENB2) tA OEA LOW (OEB) tA QA0 - QA8 (QB0 - QB8) DATA READ DATA IN OUTPUT REGISTER NEXT DATA READ 3034 drw 09 NOTE: 1. Only one of the two write enable inputs, WEN1 or WEN2, needs to go inactive to inhibit writes to the FIFO. Figure 8. Full Flag Timing WCLKA (WCLKB) tDS tDS DA0 - DA8 (DB0 - DB8) DATA WRITE 1 DATA WRITE 2 tENS tENH tENS tENS tENH tENS tENH WENA1, (WENB1) WENA2 (WENB2) (If Applicable) tENH (1) (1) tFRL tSKEW1 tSKEW1 tFRL RCLKA (RLCKB) tREF tREF tREF EFA (EFB) RENA1, RENA2 (RENB1, RENB2) OEA (OEB) LOW tA QA0-QA8 (QB0-QB8) DATA IN OUTPUT REGISTER DATA READ 3034 drw 10 NOTE: 1. When tSKEW1 ≥ minimum specification, tFRL maximum = tCLK + tSKEW1 When tSKEW1 < minimum specification, tFRL maximum = 2tCLK + tSKEW1 or tCLK + tSKEW1 The Latency Timings apply only at the Empty Boundary (EFA, EFB = LOW). Figure 9. Empty Flag Timing 11 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 tCLKH tCLKL (4) WCLKA (WCLKB) tENS tENH tENS tENH WENA1 (WENB1) WENA2 (WENB2) (If Applicable) tPAF PAFA (PAFB) Full - (m+1) words in FIFO (2) (1) Full - m words in FIFO (3) tSKEW2 tPAF RCLKA (RCLKB) tENS tENH RENA1, RENA2 (RENB1, RENB2) 3034 drw 11 NOTES: 1. m = PAF offset. 2. (256-m) words for the IDT72801; (512-m) words the IDT72811; (1,024-m) words for the IDT72821; (2,048-m) words for the IDT72831; (4,096-m) words for the IDT72841; or (8,192-m) words for the IDT72851. 3. tSKEW2 is the minimum time between a rising RCLKA (RCLKB) edge and a rising WCLKA (WCLKB) edge for PAFA (PAFB) to change during that clock cycle. If the time between the rising edge of RCLKA (RCLKB) and the rising edge of WCLKA (WCLKB) is less than tSKEW2, then PAFA (PAFB) may not change state until the next WCLKA (WCLKB) rising edge. 4. If a write is performed on this rising edge of the write clock, there will be Full - (m-1) words in FIFO A (B) when PAFA (PAFB) goes LOW. Figure 10. Programmable Full Flag Timing tCLKH tCLKL WCLKA (WCLKB) tENS tENH tENS tENH WENA1 (WENB1) WENA2 (WENB2) (If Applicable) PAEA, PAEB n words in FIFO (1) tSKEW2 n+1 words in FIFO (2) tPAE (3) tPAE RCLKA (RCLKB) tENS RENA1, RENA2 (RENB1, RENB2) tENH 3034 drw 12 NOTES: 1. n = PAE offset. 2. tSKEW2 is the minimum time between a rising WCLKA (WCLKB) edge and a rising RCLKA (RCLKB) edge for PAEA (PAEB) to change during that clock cycle. If the time between the rising edge of WCLKA (WCLKB) and the rising edge of RCLKA (RCLKB) is less than tSKEW2, then PAEA (PAEB) may not change state until the next RCLKA (RCLKB) rising edge. 3. If a read is performed on this rising edge of the read clock, there will be Empty + (n-1) words in FIFO A (B) when PAEA (PAEB) goes LOW. Figure 11. Programmable Empty Flag Timing 12 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 tCLK tCLKL WCLKA (WCLKB) tENH tENS LDA (LDB) tENS WENA1 (WENB1) tDH tDS DA0 - DA7 (DB0 - DB7) PAE OFFSET (LSB) PAE OFFSET (MSB) PAF OFFSET (LSB) PAF OFFSET (MSB) 3034 drw 13 Figure 12. Write Offset Register Timing tCLK tCLKH tCLKL RCLKA (RCLKB) tENS tENH LDA (LDB) tENS RENA1, RENA2 (RENB1, RENB2) tA QA0 - QA7 (QB0 - QB7) DATA IN OUTPUT REGISTER EMPTY OFFSET (LSB) EMPTY OFFSET (MSB) FULL OFFSET (LSB) FULL OFFSET (MSB) 3034 drw 14 Figure 13. Read Offset Register Timing 13 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 OPERATING CONFIGURATIONS can be grounded (see Figure 14). In this configuration, the Write Enable 2/ Load WENA2/LDA (WENB2/LDB) pin is set LOW at Reset so that the pin operates as a control to load and read the programmable flag offsets. SINGLE DEVICE CONFIGURATION — When FIFO A (B) is in a Single Device Configuration, the Read Enable 2 RENA2 (RENB2) control input RSA (RSB) WCLKA (WCLKB) RCLKA (RCLKB) WENA1 (WENB1) RENA1 (RENB1) IDT 72801 72811 72821 72831 72841 72851 WENA2/LDA (WENB2/LDB) DA0 - DA8 (DB0 - DB8) FFA (FFB) PAFA (PAFB) OEA (OEB) QA0 - QA8 (QB0 - QB8) EFA (EFB) PAEA (PAEB) FIFO A (B) RENA2 (RENB2) 3034 drw 15 Figure 14. Block Diagram of One of the IDT72801/72811/72821/72831/72841/72851's two FIFOs configured as a single device WIDTH EXPANSION CONFIGURATION — Word width may be increased simply by connecting the corresponding input control signals of FIFOs A and B. A composite flag should be created for each of the endpoint status flags EFA and EFB, also FFA and FFB). The partial status flags PAEA, PAFB, PAEA and PAFB can be detected from any one device. Figure 15 demonstrates an 18-bit word width using the two FIFOs contained in one IDT72801/72811/72821/72831/72841/72851. Any word width can be attained by adding additional IDT72801/72811/72821/72831/72841/ 72851s. When these devices are in a Width Expansion Configuration, the Read Enable 2 (RENA2 and RENB2) control inputs can be grounded (see Figure 15). In this configuration, the Write Enable 2/Load (WENA2/LDA, WENB2/LDB) pins are set LOW at Reset so that the pin operates as a control to load and read the programmable flag offsets. 9 RESET RSA DATA IN 18 9 DA0 - DA8 WRITE CLOCK WCLKA WRITE ENABLE WENA1 WRITE ENABLE/LOAD WENA2/LDA FULL FLAG FFA FFB DB0 - DB8 RAM ARRAY A 256x9 512x9 1,024x9 2,048x9 4,096x9 8,192x9 RSB EFA EFB RAM RCLKA ARRAY RCLKB B WCLKB 256x9 RENB1 RENA1 WENB1 512x9 1,024x9 OEB OEA1 2WENB2/LDB 2,048x9 4,096x9 8,192x9 QB0 - QB8 RENA2 EMPTY FLAG READ CLOCK READ ENABLE OUTPUT ENABLE 9 18 DATA OUT QA0 - QA8 RENB2 9 Figure 15. Block diagram of the two FIFOs contained in one IDT72801/72811/ 72821/72831/72841/72851 configured for an 18-bit width-expansion 14 3034 drw 16 Commercial And Industrial Temperature Range IDT72801/728211/72821/72831/72841/72851 TWO PRIORITY DATA BUFFER CONFIGURATION data according to type, sending one kind to FIFO A and the other kind to FIFO B. Then, at the outputs, each data type is transferred to its appropriate destination. Additional IDT72801/72811/72821/72831/72841/72851s permit more than two priority levels. Priority buffering is particularly useful in network applications. The two FIFOs contained in the IDT72801/72811/72821/72831/72841/ 72851 can be used to prioritize two different types of data shared on a system bus. When writing from the bus to the FIFO, control logic sorts the intermixed Clock Control Logic 9 Image Processing Card RAM ARRAY A RCLKA WCLKA OEA WENA1 RENA VCC Data 9 QA0-QA8 WENA2 RENA2 IDT 72801 72811 72821 72831 72841 72851 Data Voice Processing Card RAM ARRAY B WCLKB RCLKB WENB1 RAM Clock OEB2 RENB1 9 Address Control I/O Data DB0-DB8 Data QB0-QB8 WENB2 RENB2 9 I/O Data Control Logic Control 9-bit bus Control Logic Address Control 9 DA0-DA8 Processor Clock Address 9 3034 drw 17 VCC Figure 16. Block Diagram of Two Priority Configuration BIDIRECTIONAL CONFIGURATION processor can write data to a peripheral controller via FIFO A, and, in turn, the peripheral controller can write the processor via FIFO B. The two FIFOs of the IDT72801/72811/72821/72831/72841/72851 can be used to buffer data flow in two directions. In the example that follows, a RAM ARRAY A WENA2 RENA2 WENA1 9 Data 9 9-bit bus Control Logic Control OEA RENA1 DA0-DA8 QA0-QA8 IDT 72801 72811 72821 72831 72841 72851 Processor Clock Address RCLKA Peripheral Controller DMA Clock 9 Control Logic WCLKA 9-bit bus VCC RAM ARRAY B RCLKB Address Control I/O Data Data 9 WENB1 RENB1 RAM 9 9 WCLKB OEB QB0-QB8 DB0-DB8 RENB2 WENB2 9 Figure 17. Block Diagram of Bidirectional Configuration 15 3034 drw 18 DEPTH EXPANSION — IDT72801/72811/72821/72831/72841/72851 can be adapted to applications that require greater than 256/512/1,024/ 2,048/4,096/8,192 words. The existence of double enable pins on the read and write ports allow depth expansion. The Write Enable 2/Load (WENA2, WENB2) pins are used as a second write enables in a depth expansion configuration, thus the Programmable flags are set to the default values. Depth expansion is possible by using one enable input for system control while the other enable input is controlled by expansion logic to direct the flow of data. A typical application would have the expansion logic alternate data access from one device to the next in a sequential manner. These FIFOs operate in the Depth Expansion configuration when the following conditions are met: 1. WENA2/LDA and WENB2/LDB pins are held HIGH during Reset so that these pins operate as second Write Enables. 2. External logic is used to control the flow of data. Please see the Application Note" DEPTH EXPANSION OF IDT'S SYNCHRONOUS FIFOs USING THE RING COUNTER APPROACH" for details of this configuration. ORDERING INFORMATION IDT XXXXX Device Type X Power XX Speed XX Package X Process/ Temperature Range BLANK I(1) Commercial (0 C to +70 C) Industrial (-40 C to +85 C) PF TF Thin Quad Flatpack (TQFP, PN64-1) Slim Thin Quad Flatpack(STQFP, PP64-1) 10 15 25 Commercial Only Commercial and Industrial Commercial and Industrial L Low Power 72801 72811 72821 72831 72841 72851 256 x 9 Dual SyncFIFO 512 x 9 Dual SyncFIFO 1,024 x 9 Dual SyncFIFO 2,048 x 9 Dual SyncFIFO 4,096 x 9 Dual SyncFIFO 8,192 x 9 Dual SyncFIFO Clock Cycle Time (tCLK), Speed in Nanoseconds 3034 drw 19 NOTES: 1. Industrial temperature range product for 15ns and 25ns speed grade are available as a standard device. DATASHEET DOCUMENT HISTORY 04/24/2001 pgs. 4, 5 and 16 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: [email protected] PF Pkg: www.idt.com/docs/PSC4036.pdf TF Pkg: www.idt.com/docs/PSC4046.pdf The SyncFIFO is a trademark and the IDT logo is a registered trademark of Integrated Device Technology, Inc. 16