M81C55 Datasheet | OKI Electric

DESCRIPTION The MSM81C55-5 has a 2k-bit static RAM (256 bytes) with parallel I/O ports and a timer. It uses silicon gate CMOS technology and consumes a standby current of 100 micro ampere, maximum, while the chip is not selected. Featureing a maximum access time of 400 ns, the MSM81C55-5 can be used in an MSM80C85AH system without using wait states. The parallel I/O consists of two 8-bit ports and one 6-bit port (both general purpose). The MSM81C55-5 also contains a 14-bit programmable counter/timer which may be used for sequence-wave generation or terminal count-pulsing. FEATURES - High speed and low power achieved with silicon gate CMOS technology - 256 words x 8bits RAM - Single power supply, 3 to 6 V - pletely static operation - On-chip address latch . - 8-bit programmable I/O ports (port A and B) - TTL patible - RAM data hold characteristic at 2 V - 6-bit programmable I/O port (port C) - 14-bit programmable binary counter/timer - Multiplexed address/data bus - Direct interface with MSM80C85AH - 40-pin Plastic DIP (DIP40-P-600-2.54): (Product name: MSM81C55-5RS) - 44-pin Plastic QFJ (QFJ44-P-S650-1.27): (Product name: MSM81C55-5JS) - 44-pin Plastic QFP (QFP44-P-910-0.80-2K): (Product name: MSM81C55-5GS-2K) Data Shee FUNCTIONAL BLOCK DIAGRAM IO/M A AD0 - 7 CE ALE RD WR RESET Timer C Port C 6 PC0 - 5 256 - 8 Static RAM B Port B 8 PB0 - 7 Port A 8 PA0 - 7 . TIMER IN TIMER OUT VCC (+5 V) GND (0 V) . Data Sheet 4 U . 1/19 .. ¡ Semiconductor MSM81C55-5RS/GS/JS PIN CONFIGURATION (TOP VIEW) 40 pin Plastic DIP PC3 1 PC4 2 TIMER IN 3 RESET 4 PC5 5 TIMER OUT 6 IO/M 7 CE 8 RD 9 WR 10 ALE 11 AD0 12 AD1 13 AD2 14 AD3 15 AD4 16 AD5 17 AD6 18 AD7 19 GND 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 VCC PC2 PC1 PC0 PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0 PA7 PA6 PA5 PA4 PA3 PA2 PA1 PA0 44 pin Plastic QFP 42 TIMER IN 43 RESET 44...