CY7C024/0241 CY7C025/0251 4K x 16/18 and 8K x 16/18 Dual-Port Static RAM with SEM, INT, BUSY Features Functional Description • True Dual-Ported memory cells which allow simultaneous reads of the same memory location • 4K x 16 organization (CY7C024) • 4K x 18 organization (CY7C0241) • 8K x 16 organization (CY7C025) • 8K x 18 organization (CY7C0251) • 0.65-micron CMOS for optimum speed/power • High-speed access: 15 ns • Low operating power: ICC = 150 mA (typ.) • Fully asynchronous operation • Automatic power-down • Expandable data bus to 32/36 bits or more using Master/Slave chip select when using more than one device • On-chip arbitration logic • Semaphores included to permit software handshaking between ports • INT flag for port-to-port communication • Separate upper-byte and lower-byte control • Pin select for Master or Slave • Available in 84-pin PLCC and 100-pin TQFP The CY7C024/0241 and CY7C025/0251 are low-power CMOS 4K x 16/18 and 8K x 16/18 dual-port static RAMs. Various arbitration schemes are included on the CY7C024/0241 and CY7C025/0251 to handle situations when multiple processors access the same piece of data. Two ports are provided, permitting independent, asynchronous access for reads and writes to any location in memory. The CY7C024/0241 and CY7C025/0251 can be utilized as standalone 16-/18-bit dual-port static RAMs or multiple devices can be combined in order to function as a 32-/36-bit or wider master/slave dual-port static RAM. An M/S pin is provided for implementing 32-/36-bit or wider memory applications without the need for separate master and slave devices or additional discrete logic. Application areas include interprocessor/multiprocessor designs, communications status buffering, and dual-port video/graphics memory. Each port has independent control pins: Chip Enable (CE), Read or Write Enable (R/W), and Output Enable (OE). Two flags are provided on each port (BUSY and INT). BUSY signals that the port is trying to access the same location currently being accessed by the other port. The Interrupt Flag (INT) permits communication between ports or systems by means of a mail box. The semaphores are used to pass a flag, or token, from one port to the other to indicate that a shared resource is in use. The semaphore logic is comprised of eight shared latches. Only one side can control the latch (semaphore) at any time. Control of a semaphore indicates that a shared resource is in use. An automatic power-down feature is controlled independently on each port by a chip select (CE) pin. The CY7C024/0241 and CY7C025/0251 are available in 84-pin PLCCs (CY7C024 and CY7C025 only) and 100-pin Thin Quad Plastic Flatpack (TQFP). v Logic Block Diagram R/WL UB L R/WR UBR LB L CE L OE L CE R OE R LBR [3] I/O 8L – I/O 15L I/O8R – I/O15R[3] I/O CONTROL I/O CONTROL [2] I/O 0R– I/O 7R [2] I/O 0L – I/O 7L BUSYL (CY7C025/0251) [1] [1] BUSYR A12R (CY7C025/0251) A12L A11L MEMORY ARRAY ADDRESS DECODER A11R ADDRESS DECODER A0L A 0R CE L OE L INTERRUPT SEMAPHORE ARBITRATION UB L LB L R/W L SEM L INT L Cypress Semiconductor Corporation Document #: 38-06035 Rev. *B • 3901 North First Street CE R OE R UB R LB R R/W R SEM R M/S • 7C024–1 INTR San Jose • CA 95134 • 408-943-2600 Revised June 22, 2004 CY7C024/0241 CY7C025/0251 Notes: 1. BUSY is an output in master mode and an input in slave mode. 2. I/O0 –I/O8 on the CY7C0241/0251. 3. I/O9 –I/O17 on the CY7C0241/0251. Document #: 38-06035 Rev. *B Page 2 of 20 CY7C024/0241 CY7C025/0251 Pin Configurations 9L A 8L A 10L A LB L NC [4] A11L SEM L CEL UB L R/WL GND I/O 1L I/O0L OE L V CC I/O2L I/O4L I/O3L I/O5L I/O7L I/O6L 84-Pin PLCC Top View 11 10 9 8 7 6 5 4 3 2 1 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 CY7C024/5 65 64 63 62 61 60 59 A7L A6L A5L A4L A3L A2L A1L A0L INTL BUSYL GND M/S BUSYR INTR A0R A1R A2R A3R A4R A5R A6R A10R A 9R A 8R A 7R NC [5] A11R GND SEMR CER UB R LB R OE R R/WR GND I/O15R I/O13R I/O14R I/O11R I/O12R I/O 9R 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 58 28 57 29 56 30 55 31 54 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 I/O10R I/O8L I/O9L I/O10L I/O11L I/O12L I/O13L GND I/O14L I/O15L VCC GND I/O0R I/O1R I/O2R VCC I/O3R I/O4R I/O5R I/O6R I/O7R I/O8R 7C024–1 A7L A6L A9L A8L UBL LBL NC [4] A11L A10L OEL VCC R/WL SEML CEL I/O1L I/O0L I/O4L I/O3L I/O2L GND I/O9L I/O8L I/O7L I/O6L I/O5L 100-Pin TQFP Top View 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 NC NC NC NC I/O10L I/O11L I/O12L I/O13L GND I/O14L I/O15L VCC GND I/O0R I/O1R I/O2R VCC I/O3R I/O4R I/O5R I/O6R NC NC NC NC 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 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 CY7C024/5 NC NC NC NC A5L A4L A3L A2L A1L A0L INTL BUSYL GND M/S BUSYR INTR A0R A1R A2R A3R A4R NC NC NC NC 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 A7R A6R A5R NC[5] A11R A10R A9R A8R R/WR GND SEMR CER UBR LBR GND I/O15R ŒR I/O13R I/O14R I/O7R I/O8R I/O9R I/O10R I/O11R I/O12R 7C024–2 Notes: 4. A12L on the CY7C025/0251. 5. A12R on the CY7C025/0251. Document #: 38-06035 Rev. *B Page 3 of 20 CY7C024/0241 CY7C025/0251 Pin Configurations (continued) A7L A6L A9L A8L UBL LBL NC [4] A11L A10L OEL VCC R/WL SEML CEL I/O1L I/O0L I/O4L I/O3L I/O2L GND I/O10L I/O9L I/O7L I/O6L I/O5L 100-Pin TQFP Top View 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 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 NC NC I/O8L I/O17L I/O11L I/O12L I/O13L I/O14L GND I/O15L I/O16L VCC GND I/O0R I/O1R I/O2R VCC I/O3R I/O4R I/O5R I/O6R I/O8R I/O17R NC NC 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 CY7C0241/0251 NC NC NC NC A5L A4L A3L A2L A1L A0L INTL BUSYL GND M/S BUSYR INTR A0R A1R A2R A3R A4R NC NC NC NC 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 A7R A6R A5R NC [5] A11R A10R A9R A8R I/O10R I/O11R I/O12R I/O13R I/O14R I/O15R GND I/O16R OER R/WR GND SEMR CER UBR LBR I/O7R I/O9R 7C024–3 Pin Definitions Left Port Right Port Description CEL CER Chip Enable R/WL R/WR Read/Write Enable OEL OER Output Enable A0L–A11/12L A0R–A11/12R Address I/O0L–I/O15/17L I/O0R–I/O15/17R Data Bus Input/Output SEML SEMR Semaphore Enable UBL UBR Upper Byte Select LBL LBR Lower Byte Select INTL INTR Interrupt Flag BUSYL BUSYR Busy Flag M/S Master or Slave Select VCC Power GND Ground Selection Guide 7C024/0241–15 7C025/0251–15 7C024/0241–25 7C025/0251–25 7C024/0241–35 7C025/0251–35 7C024/0241–55 7C025/0251–55 Maximum Access Time (ns) 15 25 35 55 Typical Operating Current (mA) 190 170 160 150 Typical Standby Current for ISB1 (mA) 50 40 30 20 Document #: 38-06035 Rev. *B Page 4 of 20 CY7C024/0241 CY7C025/0251 Maximum Ratings [6] Static Discharge Voltage........................................... >2001V (per MIL-STD-883, Method 3015) (Above which the useful life may be impaired. For user guidelines, not tested.) Latch-Up Current.................................................... >200 mA Storage Temperature .................................–65°C to +150°C Operating Range Ambient Temperature with Power Applied.............................................–55°C to +125°C Supply Voltage to Ground Potential ............... –0.3V to +7.0V DC Voltage Applied to Outputs in High Z State ............................................... –0.5V to +7.0V Range Ambient Temperature VCC Commercial 0°C to +70°C 5V ± 10% –40°C to +85°C 5V ± 10% Industrial [7] DC Input Voltage ......................................... –0.5V to +7.0V Output Current into Outputs (LOW) .............................20 mA Electrical Characteristics Over the Operating Range 7C024/0241–15 7C025/0251–15 Parameter Description Test Conditions 7C024/0241–25 7C025/0251–25 Min. Typ. Max. Min. Typ. VOH Output HIGH Voltage VCC = Min., IOH = –4.0 mA VOL Output LOW Voltage VCC = Min., IOL = 4.0 mA VIH Input HIGH Voltage 2.2 VIL Input LOW Voltage –0.7 0.8 –0.7 0.8 V IIX Input Leakage Current GND ≤ VI ≤ VCC –10 +10 –10 +10 µA IOZ Output Leakage Current Output Disabled, GND ≤ VO ≤ VCC –10 +10 –10 +10 µA ICC Operating Current VCC = Max., IOUT = 0 mA, Outputs Disabled Com’l 190 300 170 250 mA Ind 200 320 170 290 Standby Current (Both Ports TTL Levels) CEL and CER ≥ VIH, f = fMAX[8] Com’l 50 70 40 60 Ind 50 70 Standby Current (One Port TTL Level) CEL or CER ≥ VIH, f = fMAX[8] Com’l 120 180 100 150 Ind 120 180 100 170 Standby Current (Both Ports CMOS Levels) Both Ports CE and CER ≥ VCC – 0.2V, VIN ≥ VCC – 0.2V or VIN ≤ 0.2V, f = 0[8] Com’l 3 15 3 15 Ind 3 15 3 15 Standby Current (Both Ports CMOS Levels) One Port CEL or CER ≥ VCC – 0.2V, VIN ≥ VCC – 0.2V or VIN ≤ 0.2V, Active Port Outputs, f = fMAX[8] Com’l 110 160 90 130 Ind 110 160 90 150 ISB1 ISB2 ISB3 ISB4 2.4 Max. Unit 2.4 V 0.4 0.4 2.2 V V mA 75 mA mA mA Notes: 6. The Voltage on any input or sI/O pin cannot exceed the power pin during power-up 7. Pulse width < 20 ns. 8. fMAX = 1/tRC = All inputs cycling at f = 1/tRC (except output enable). f = 0 means no address or control lines change. This applies only to inputs at CMOS level standby ISB3. Document #: 38-06035 Rev. *B Page 5 of 20 CY7C024/0241 CY7C025/0251 Electrical Characteristics Over the Operating Range (continued) 7C024/0241–35 7C025/0251–35 Parameter Description Test Conditions Min. Typ. 7C024/0241–55 7C025/0251–55 Max. Min. Typ. Max. Unit VOH Output HIGH Voltage VCC = Min., IOH = –4.0 mA VOL Output LOW Voltage VCC = Min., IOL = 4.0 mA VIH Input HIGH Voltage VIL Input LOW Voltage IIX Input Leakage Current IOZ Output Leakage Current Output Disabled, GND ≤ VO ≤ VCC ICC Operating Current VCC = Max., IOUT = 0 mA, Outputs Disabled Com’l 160 230 Ind 160 ISB1 Standby Current (Both Ports TTL Levels) CEL and CER ≥ VIH, f = fMAX[8] Com’l 30 Ind ISB2 Standby Current (One Port TTL Level) CEL or CER ≥ VIH, f = fMAX[8] ISB3 Standby Current (Both Ports CMOS Levels) Both Ports CE and CER ≥ VCC – 0.2V, VIN ≥ VCC – 0.2V or VIN ≤ 0.2V, f = 0[8] Standby Current (Both Ports CMOS Levels) One Port CEL or CER ≥ VCC – 0.2V, VIN ≥ VCC – 0.2V or VIN ≤ 0.2V, Active Port Outputs, f = fMAX[8] ISB4 2.4 2.4 V 0.4 0.4 2.2 V 2.2 V –0.7 0.8 –0.7 0.8 V –10 +10 –10 +10 µA –10 +10 –10 +10 µA 150 230 mA 260 150 260 50 20 50 30 65 20 65 Com’l 85 135 75 135 Ind 85 150 75 150 Com’l 3 15 3 15 Ind 3 15 3 15 Com’l 80 120 70 120 Ind 80 135 70 135 GND ≤ VI ≤ VCC mA mA mA mA Capacitance[9] Parameter Description CIN Input Capacitance COUT Output Capacitance Test Conditions TA = 25×C, f = 1 MHz, VCC = 5.0V Max. Unit 10 pF 10 pF AC Test Loads and Waveforms 5V 5V R1 = 893Ω RTH = 250Ω OUTPUT OUTPUT R1 = 893Ω OUTPUT C = 30pF C = 30 pF R2 = 347Ω C = 5 pF VTH = 1.4V 7C024–8 7C024–9 (a) Normal Load (Load 1) R2 = 347Ω 7C024–10 (c) Three-State Delay (Load 3) (b) Thévenin Equivalent (Load 1) ALL INPUT PULSES OUTPUT 3.0V C = 30 pF GND 10% 90% 90% 10% ≤ 3 ns Load (Load 2) 7C024–11 Note: 9. Tested initially and after any design or process changes that may affect these parameters. Document #: 38-06035 Rev. *B ≤ 3 ns 7C024–12 Page 6 of 20 CY7C024/0241 CY7C025/0251 Switching Characteristics Over the Operating Range[10] 7C024/0241–15 7C025/0251–15 Parameter Description Min. Max. 7C024/0241–25 7C025/0251–25 Min. Max. 7C024/0241–35 7C025/0251–35 Min. Max. 7C024/0241–55 7C025/0251–55 Min. Max. Unit READ CYCLE tRC Read Cycle Time tAA Address to Data Valid tOHA Output Hold From Address Change tACE[11] CE LOW to Data Valid tDOE OE LOW to Data Valid tLZOE[12, 13, 14] OE Low to Low Z tHZOE[12, 13, 14] 15 15 3 35 25 3 15 3 3 3 20 3 15 3 ns 55 35 13 3 10 55 35 25 10 3 OE HIGH to High Z tLZCE[12, 13, 14] CE LOW to Low Z 25 ns 55 ns 25 ns 3 20 3 ns ns 25 3 ns ns tHZCE[12, 13, 14] CE HIGH to High Z tPU[14] CE LOW to Power-Up tPD[14] tABE[11] CE HIGH to Power-Down 15 25 25 55 ns Byte Enable Access Time 15 25 35 55 ns 10 0 15 0 20 0 25 0 ns ns WRITE CYCLE tWC Write Cycle Time 15 25 35 55 ns tSCE[11] CE LOW to Write End 12 20 30 35 ns tAW Address Set-Up to Write End 12 20 30 35 ns tHA Address Hold From Write End 0 0 0 0 ns tSA[11] Address Set-Up to Write Start 0 0 0 0 ns tPWE Write Pulse Width 12 20 25 35 ns tSD Data Set-Up to Write End 10 15 15 20 ns tHD Data Hold From Write End 0 0 0 0 ns tHZWE[13, 14] tLZWE[13, 14] tWDD[15] tDDD[15] R/W LOW to High Z R/W HIGH to Low Z 10 0 15 0 20 0 25 0 ns ns Write Pulse to Data Delay 30 50 60 70 ns Write Data Valid to Read Data Valid 25 35 35 45 ns Notes: 10. Test conditions assume signal transition time of 3 ns or less, timing reference levels of 1.5V, input pulse levels of 0 to 3.0V, and output loading of the specified IOI/IOH and 30-pF load capacitance. 11. To access RAM, CE=L, UB=L, SEM=H. To access semaphore, CE=H and SEM=L. Either condition must be valid for the entire tSCE time. 12. At any given temperature and voltage condition for any given device, tHZCE is less than tLZCE and tHZOE is less than tLZOE. 13. Test conditions used are Load 3. 14. This parameter is guaranteed but not tested. 15. For information on port-to-port delay through RAM cells from writing port to reading port, refer to Read Timing with Busy waveform. Document #: 38-06035 Rev. *B Page 7 of 20 CY7C024/0241 CY7C025/0251 Switching Characteristics Over the Operating Range[10] (continued) 7C024/0241–15 7C025/0251–15 Parameter Description Min. Max. 7C024/0241–25 7C025/0251–25 Min. Max. 7C024/0241–35 7C025/0251–35 Min. Max. 7C024/0241–55 7C025/0251–55 Min. Max. Unit [16] BUSY TIMING tBLA BUSY LOW from Address Match 15 20 20 45 ns tBHA BUSY HIGH from Address Mismatch 15 20 20 40 ns tBLC BUSY LOW from CE LOW 15 20 20 40 ns tBHC BUSY HIGH from CE HIGH 15 20 20 35 ns tPS Port Set-Up for Priority 5 5 5 5 ns tWB R/W HIGH after BUSY (Slave) 0 0 0 0 ns tWH R/W HIGH after BUSY HIGH (Slave) 13 20 30 40 ns tBDD[17] BUSY HIGH to Data Valid INTERRUPT Note 17 Note 17 Note 17 Note 17 ns TIMING[16] tINS INT Set Time 15 20 25 30 ns tINR INT Reset Time 15 20 25 30 ns SEMAPHORE TIMING tSOP SEM Flag Update Pulse (OE or SEM) 10 12 15 20 ns tSWRD SEM Flag Write to Read Time 5 10 10 15 ns tSPS SEM Flag Contention Window 5 10 10 15 ns tSAA SEM Address Access Time 15 Data Retention Mode The CY7C024/0241 is designed with battery backup in mind. Data retention voltage and supply current are guaranteed over temperature. The following rules insure data retention: 25 55 ns Timing Data Retention Mode VCC 4.5V 1. Chip enable (CE) must be held HIGH during data retention, within VCC to VCC – 0.2V. 2. CE must be kept between VCC – 0.2V and 70% of VCC during the power-up and power-down transitions. 35 VCC > 2.0V 4.5V VCC to VCC – 0.2V CE 3. The RAM can begin operation >tRC after VCC reaches the minimum operating voltage (4.5 volts). tRC V IH 7C024–13 Parameter ICCDR1 Test Conditions[18] @ VCCDR = 2V Max. Unit 1.5 mA Notes: 16. Test conditions used are Load 2. 17. tBDD is a calculated parameter and is the greater of tWDD– tPWE (actual) or tDDD– tSD (actual). 18. CE = VCC, Vin = GND to VCC, TA = 25°C. This parameter is guaranteed but not tested. Document #: 38-06035 Rev. *B Page 8 of 20 CY7C024/0241 CY7C025/0251 Switching Waveforms Read Cycle No. 1 (Either Port Address Access)[19, 20, 21] tRC ADDRESS tOHA DATA OUT tAA tOHA PREVIOUS DATA VALID DATA VALID 7C024–14 Read Cycle No. 2 (Either Port CE/OE Access)[19, 22, 23] tACE CE and LB or UB tHZCE tDOE OE tHZOE tLZOE DATA VALID DATA OUT tLZCE tPU tPD ICC CURRENT ISB 7C024–15 Read Cycle No. 3 (Either Port)[19, 21, 22, 22, 23] tRC ADDRESS tAA tOHA UB or LB tHZCE tLZCE tABE CE tHZCE tACE tLZCE DATA OUT 7C024–16 Notes: 19. R/W is HIGH for read cycles 20. Device is continuously selected CE = VIL and UB or LB = VIL. This waveform cannot be used for semaphore reads. 21. OE = VIL. 22. Address valid prior to or coincident with CE transition LOW. 23. To access RAM, CE = VIL, UB or LB = VIL, SEM = VIH. To access semaphore, CE = VIH, SEM = VIL. Document #: 38-06035 Rev. *B Page 9 of 20 CY7C024/0241 CY7C025/0251 Switching Waveforms (continued) Write Cycle No. 1: R/W Controlled Timing[24, 25, 26, 27] tWC ADDRESS tHZOE [30] OE tAW CE [28,29] tPWE[27] tSA tHA R/W tHZWE[30] DATA OUT tLZWE NOTE 31 NOTE 31 tSD tHD DATA IN 7C024–17 Write Cycle No. 2: CE Controlled Timing[24, 25, 26, 32] tWC ADDRESS tAW CE [28,29] tSA tSCE tHA R/W tSD tHD DATA IN 7C024–18 Notes: 24. R/W must be HIGH during all address transitions. 25. A write occurs during the overlap (tSCE or tPWE) of a LOW CE or SEM and a LOW UB or LB. 26. tHA is measured from the earlier of CE or R/W or (SEM or R/W) going HIGH at the end of write cycle. 27. If OE is LOW during a R/W controlled write cycle, the write pulse width must be the larger of tPWE or (tHZWE + tSD) to allow the I/O drivers to turn off and data to be placed on the bus for the required tSD. If OE is HIGH during an R/W controlled write cycle, this requirement does not apply and the write pulse can be as short as the specified tPWE. 28. To access RAM, CE = VIL, SEM = VIH. 29. To access upper byte, CE = VIL, UB = VIL, SEM = VIH. To access lower byte, CE = VIL, LB = VIL, SEM = VIH. 30. Transition is measured ±500 mV from steady state with a 5-pF load (including scope and jig). This parameter is sampled and not 100% tested. 31. During this period, the I/O pins are in the output state, and input signals must not be applied. 32. If the CE or SEM LOW transition occurs simultaneously with or after the R/W LOW transition, the outputs remain in the high-impedance state. Document #: 38-06035 Rev. *B Page 10 of 20 CY7C024/0241 CY7C025/0251 Switching Waveforms (continued) Semaphore Read After Write Timing, Either Side[33] tOHA tAA A 0–A 2 VALID ADRESS VALID ADRESS tAW tACE tHA SEM tSCE tSOP tSD I/O 0 DATAIN VALID tSA tPWE DATAOUT VALID tHD R/W tSWRD tDOE tSOP OE WRITE CYCLE READ CYCLE 7C024–19 Timing Diagram of Semaphore Contention[34, 35, 36] A0L –A2L MATCH R/WL SEM L tSPS A 0R –A 2R MATCH R/WR SEM R 7C024–20 Notes: 33. CE = HIGH for the duration of the above timing (both write and read cycle). 34. I/O0R = I/O0L = LOW (request semaphore); CER = CEL = HIGH. 35. Semaphores are reset (available to both ports) at cycle start. 36. If tSPS is violated, the semaphore will definitely be obtained by one side or the other, but which side will get the semaphore is unpredictable. Document #: 38-06035 Rev. *B Page 11 of 20 CY7C024/0241 CY7C025/0251 Switching Waveforms (continued) Timing Diagram of Read with BUSY (M/S=HIGH)[37] tWC ADDRESSR MATCH tPWE R/WR tSD DATA INR tHD VALID tPS ADDRESSL MATCH tBLA tBHA BUSYL tBDD tDDD DATA OUTL VALID tWDD 7C024–21 Write Timing with Busy Input (M/S=LOW) tPWE R/W BUSY tWB tWH 7C024–22 Note: 37. CEL = CER = LOW. Document #: 38-06035 Rev. *B Page 12 of 20 CY7C024/0241 CY7C025/0251 Switching Waveforms (continued) Busy Timing Diagram No.1 (CE Arbitration)[38] CELValid First: ADDRESS L,R ADDRESS MATCH CEL tPS CER tBLC tBHC BUSYR 7C024–23 CER Valid First: ADDRESS L,R ADDRESS MATCH CER tPS CE L tBLC tBHC BUSYL 7C024–24 Busy Timing Diagram No.2 (Address Arbitration)[38] Left Address Valid First tRC or tWC ADDRESS L ADDRESS MATCH ADDRESS MISMATCH tPS ADDRESSR tBLA tBHA BUSY R 7C024–25 Right Address Valid First: tRC or tWC ADDRESSR ADDRESS MATCH ADDRESS MISMATCH tPS ADDRESSL tBLA tBHA BUSY L 7C024–26 Note: 38. If tPS is violated, the busy signal will be asserted on one side or the other, but there is no guarantee to which side BUSY will be asserted. Document #: 38-06035 Rev. *B Page 13 of 20 CY7C024/0241 CY7C025/0251 Switching Waveforms (continued) Interrupt Timing Diagrams Left Side Sets INTR : ADDRESSL tWC WRITE FFF (1FFF CY7C025) tHA[39] CE L R/W L INT R tINS [40] 7C024–27 Right Side Clears INT R : tRC READ FFF (1FFF CY7C025) ADDRESSR CE R tINR [40] R/WR OE R INTR 7C024–28 Right Side Sets INT L: tWC ADDRESSR WRITE FFE (1FFE CY7C025) tHA[39] CE R R/W R INT L tINS[40] 7C024–29 Left Side Clears INT L : tRC READ FFE (1FFE CY7C025) ADDRESSR CE L tINR[40] R/W L OE L INT L 7C024–30 Notes: 39. tHA depends on which enable pin (CEL or R/WL) is deasserted first. 40. tINS or tINR depends on which enable pin (CEL or R/WL) is asserted last. Document #: 38-06035 Rev. *B Page 14 of 20 CY7C024/0241 CY7C025/0251 Architecture The CY7C024/0241 and CY7C025/0251 consist of an array of 4K words of 16/18 bits each and 8K words of 16/18 bits each of dual-port RAM cells, I/O and address lines, and control signals (CE, OE, R/W). These control pins permit independent access for reads or writes to any location in memory. To handle simultaneous writes/reads to the same location, a BUSY pin is provided on each port. Two interrupt (INT) pins can be utilized for port-to-port communication. Two semaphore (SEM) control pins are used for allocating shared resources. With the M/S pin, the CY7C024/0241 and CY7C025/0251 can function as a master (BUSY pins are outputs) or as a slave (BUSY pins are inputs). The CY7C024/0241 and CY7C025/0251 have an automatic power-down feature controlled by CE. Each port is provided with its own output enable control (OE), which allows data to be read from the device. Functional Description Write Operation Data must be set up for a duration of tSD before the rising edge of R/W in order to guarantee a valid write. A write operation is controlled by either the R/W pin (see Write Cycle No. 1 waveform) or the CE pin (see Write Cycle No. 2 waveform). Required inputs for non-contention operations are summarized in Table 1. If a location is being written to by one port and the opposite port attempts to read that location, a port-to-port flowthrough delay must occur before the data is read on the output; otherwise the data read is not deterministic. Data will be valid on the port tDDD after the data is presented on the other port. Read Operation When reading the device, the user must assert both the OE and CE pins. Data will be available tACE after CE or tDOE after OE is asserted. If the user of the CY7C024/0241 or CY7C025/0251 wishes to access a semaphore flag, then the SEM pin must be asserted instead of the CE pin, and OE must also be asserted. Interrupts The upper two memory locations may be used for message passing. The highest memory location (FFF for the CY7C024/0241, 1FFF for the CY7C025/0251) is the mailbox for the right port and the second-highest memory location (FFE for the CY7C024/0241, 1FFE for the CY7C025/0251) is the mailbox for the left port. When one port writes to the other port’s mailbox, an interrupt is generated to the owner. The interrupt is reset when the owner reads the contents of the mailbox. The message is user defined. Each port can read the other port’s mailbox without resetting the interrupt. The active state of the BUSY signal (to a port) prevents the port from setting the interrupt to the winning port. Also, an active BUSY to a port prevents that port from reading its own mailbox and thus resetting the interrupt to it. If your application does not require message passing, do not connect the interrupt pin to the processor’s interrupt request input pin. The operation of the interrupts and their interaction with Busy are summarized in Table 2. Busy tention). If both ports’ CEs are asserted and an address match occurs within tPS of each other, the busy logic will determine which port has access. If tPS is violated, one port will definitely gain permission to the location, but which one is not predictable. BUSY will be asserted tBLA after an address match or tBLC after CE is taken LOW. Master/Slave A M/S pin is provided in order to expand the word width by configuring the device as either a master or a slave. The BUSY output of the master is connected to the BUSY input of the slave. This will allow the device to interface to a master device with no external components. Writing to slave devices must be delayed until after the BUSY input has settled (tBLC or tBLA). Otherwise, the slave chip may begin a write cycle during a contention situation.When tied HIGH, the M/S pin allows the device to be used as a master and, therefore, the BUSY line is an output. BUSY can then be used to send the arbitration outcome to a slave. Semaphore Operation The CY7C024/0241 and CY7C025/0251 provide eight semaphore latches, which are separate from the dual-port memory locations. Semaphores are used to reserve resources that are shared between the two ports.The state of the semaphore indicates that a resource is in use. For example, if the left port wants to request a given resource, it sets a latch by writing a zero to a semaphore location. The left port then verifies its success in setting the latch by reading it. After writing to the semaphore, SEM or OE must be deasserted for tSOP before attempting to read the semaphore. The semaphore value will be available tSWRD + tDOE after the rising edge of the semaphore write. If the left port was successful (reads a zero), it assumes control of the shared resource, otherwise (reads a one) it assumes the right port has control and continues to poll the semaphore. When the right side has relinquished control of the semaphore (by writing a one), the left side will succeed in gaining control of the semaphore. If the left side no longer requires the semaphore, a one is written to cancel its request. Semaphores are accessed by asserting SEM LOW. The SEM pin functions as a chip select for the semaphore latches (CE must remain HIGH during SEM LOW). A0–2 represents the semaphore address. OE and R/W are used in the same manner as a normal memory access. When writing or reading a semaphore, the other address pins have no effect. When writing to the semaphore, only I/O0 is used. If a zero is written to the left port of an available semaphore, a one will appear at the same semaphore address on the right port. That semaphore can now only be modified by the side showing zero (the left port in this case). If the left port now relinquishes control by writing a one to the semaphore, the semaphore will be set to one for both sides. However, if the right port had requested the semaphore (written a zero) while the left port had control, the right port would immediately own the semaphore as soon as the left port released it. Table 3 shows sample semaphore operations. When reading a semaphore, all sixteen/eighteen data lines output the semaphore value. The read value is latched in an output register to prevent the semaphore from changing state during a write from the other port. If both ports attempt to access the semaphore within tSPS of each other, the semaphore will definitely be obtained by one side or the other, but there is no guarantee which side will control the semaphore. The CY7C024/0241 and CY7C025/0251 provide on-chip arbitration to resolve simultaneous memory location access (conDocument #: 38-06035 Rev. *B Page 15 of 20 CY7C024/0241 CY7C025/0251 Table 1. Non-Contending Read/Write Inputs Outputs I/O0–I/O7[2] I/O8–I/O15[3] CE R/W OE UB LB SEM Operation H X X X X H High Z High Z Deselected: Power-Down X X X H H H High Z High Z Deselected: Power-Down L L X L H H High Z Data In Write to Upper Byte Only L L X H L H Data In High Z Write to Lower Byte Only L L X L L H Data In Data In Write to Both Bytes L H L L H H High Z Data Out Read Upper Byte Only L H L H L H Data Out High Z Read Lower Byte Only L H L L L H Data Out Data Out Read Both Bytes X X H X X X High Z High Z Outputs Disabled H H L X X L Data Out Data Out Read Data in Semaphore Flag X H L H H L Data Out Data Out Read Data in Semaphore Flag H X X X L Data In Data In Write DIN0 into Semaphore Flag X X H H L Data In Data In Write DIN0 into Semaphore Flag L X X L X L Not Allowed L X X X L L Not Allowed Table 2. Interrupt Operation Example (assumes BUSYL=BUSYR=HIGH)[41] Left Port Function Right Port R/WL CEL OEL A0L–11L INTL R/WR CER OER A0R–11R INTR Set Right INTR Flag L L X (1)FFF X X X X X L[43] Reset Right INTR Flag X X X X X X L L (1)FFF H[42] Set Left INTL Flag X X X X L[42] L L X (1)FFE X [43] X X X X X Reset Left INTL Flag Document #: 38-06035 Rev. *B X L L (1)FFE H Page 16 of 20 CY7C024/0241 CY7C025/0251 Table 3. Semaphore Operation Example I/O0–I/O15/17 Left I/O0–I/O15/17 Right No action 1 1 Semaphore free Left port writes 0 to semaphore 0 1 Left Port has semaphore token Right port writes 0 to semaphore 0 1 No change. Right side has no write access to semaphore. Left port writes 1 to semaphore 1 0 Right port obtains semaphore token Left port writes 0 to semaphore 1 0 No change. Left port has no write access to semaphore Right port writes 1 to semaphore 0 1 Left port obtains semaphore token Left port writes 1 to semaphore 1 1 Semaphore free Right port writes 0 to semaphore 1 0 Right port has semaphore token Right port writes 1 to semaphore 1 1 Semaphore free Left port writes 0 to semaphore 0 1 Left port has semaphore token Left port writes 1 to semaphore 1 1 Semaphore free Function Status Ordering Information 4K x16 Dual-Port SRAM Speed (ns) 15 25 35 55 Ordering Code Package Name CY7C024–15AC A100 CY7C024–15JC J83 CY7C024–25AC A100 CY7C024–25JC J83 CY7C024–25AI A100 CY7C024–25JI J83 CY7C024–35AC A100 CY7C024–35JC J83 CY7C024–35AI A100 CY7C024–35JI J83 CY7C024–55AC A100 CY7C024–55JC J83 CY7C024–55AI A100 CY7C024–55JI J83 Package Type 100-Pin Thin Quad Flat Pack Operating Range Commercial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Commercial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Industrial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Commercial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Industrial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Commercial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Industrial 84-Lead Plastic Leaded Chip Carrier Notes: 41. A0L–12L and A0R–12R, 1FFF/1FFE for the CY7C025. 42. If BUSYR=L, then no change. 43. If BUSYL=L, then no change. Document #: 38-06035 Rev. *B Page 17 of 20 CY7C024/0241 CY7C025/0251 Ordering Information (continued) 8K x 16 Dual-Port SRAM Speed (ns) 15 25 35 55 Ordering Code CY7C025–15AC Package Name A100 Package Type 100-Pin Thin Quad Flat Pack Operating Range Commercial CY7C025–15JC J83 CY7C025–15AI A100 100-Pin Thin Quad Flat Pack Industrial CY7C025–25AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C025–25JC J83 CY7C025–25AI A100 CY7C025–25JI J83 CY7C025–35AC A100 CY7C025–35JC J83 CY7C025–35AI A100 CY7C025–35JI J83 CY7C025–55AC A100 CY7C025–55JC J83 CY7C025–55AI A100 CY7C025–55JI J83 84-Lead Plastic Leaded Chip Carrier 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Industrial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Commercial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Industrial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Commercial 84-Lead Plastic Leaded Chip Carrier 100-Pin Thin Quad Flat Pack Industrial 84-Lead Plastic Leaded Chip Carrier 4K x 18 Dual-Port SRAM Speed (ns) 15 25 35 55 Ordering Code Package Name Package Type Operating Range CY7C0241–15AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0241–15AI A100 100-Pin Thin Quad Flat Pack Industrial CY7C0241–25AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0241–25AI A100 100-Pin Thin Quad Flat Pack Industrial CY7C0241–35AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0241–35AI A100 100-Pin Thin Quad Flat Pack Industrial CY7C0241–55AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0241–55AI A100 100-Pin Thin Quad Flat Pack Industrial 8K x 18 Dual-Port SRAM Speed (ns) Ordering Code Package Name Package Type Operating Range 15 CY7C0251–15AC A100 100-Pin Thin Quad Flat Pack Commercial 25 CY7C0251–25AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0251–25AI A100 100-Pin Thin Quad Flat Pack Industrial CY7C0251–35AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0251–35AI A100 100-Pin Thin Quad Flat Pack Industrial CY7C0251–55AC A100 100-Pin Thin Quad Flat Pack Commercial CY7C0251–55AI A100 100-Pin Thin Quad Flat Pack Industrial 35 55 Document #: 38-06035 Rev. *B Page 18 of 20 © Cypress Semiconductor Corporation, 2004. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. CY7C024/0241 CY7C025/0251 Package Diagrams 100-Pin Thin Plastic Quad Flat Pack (TQFP) A100 51-85048-*B 84-Lead Plastic Leaded Chip Carrier J83 51-85006-*A Document #: 38-06035 Rev. *B Page 19 of 20 CY7C024/0241 CY7C025/0251 Document Title: CY7C024/0241, CY7C025/0251 4K x 16/18 and 8K x 16/18 Dual-Port Static RAM with Sem, Int, Busy Document Number: 38-06035 REV. ECN NO. Issue Date Orig. of Change Description of Change ** 110177 09/29/01 SZV Change from Spec number: 38-00255 to 38-06035 *A 122286 12/27/02 RBI Power up requirements added to Maximum Ratings Information *B 236754 See ECN YDT Removed cross information from features section Document #: 38-06035 Rev. *B Page 20 of 20