inter

8155/8156/8155-2/8156-2

2048 BIT STATIC MOS RAM WITH I/O PORTS AND TIMER

 

8085A

8085A-2

~

 

 

 

.

 

 

Enable

 

8155

8155-2

 

 

ACTIVE LOW

 

8156

8156-2

 

 

ACTIVE HIGH

2S6 Word x 8 Bits

 

 

1 Programmable 6-Bit 1/0 Port

Single +5V Power Supply

 

 

Programmable 14-Bit Binary Counterl

Completely Static Operation

 

 

 

Timer

 

 

 

Multiplexed Address and Data Bus

Internal Address Latch

 

 

 

 

 

 

 

2 Programmable 8 Bit 1/0 Ports

 

 

40 Pin DIP

The 8155 and 8156 are RAM and I/O chips to be used in the MCS-85'·microcomputer system. The RAM portion is designed with 2048 static cells organized as 256 x 8. They have a maximum access time of 400 ns to permit use with no wait states in 8085A CPU. The 8155-2 and 13156-2 have maximum access times of 330 ns for use with the 8085A-2.

The 110 portion consists of three general purpose 110 ports. One of the three ports can be programmed to be status pins, thus allowing the other two ports to operate in handshake mode.

A14-bit programmable counter/timer is also included on chip to provide either a square wave or terminal count pulse for the CPU system depending on timer mode.

PIN CONFIGURATION

 

BLOCK DIAGRAM

 

 

pc.

vee

 

 

 

 

 

pc.

pCz

 

 

 

 

 

TIMER IN

PC,

101M

 

G

PORT A

 

RESET

PCo

 

 

a

PAs-,

PC.

PB,

ADO-7

256 X a

 

 

TIMER OUT

PBs

 

 

 

STATIC

 

 

101M

PBs

*

RAM

 

 

 

CE OR CE*

PB.

 

G

 

ps,,-,

ifD

PB.

 

 

ALE

 

 

 

 

 

 

 

 

WR

PBz

AD

 

 

 

ALE

PB,

 

 

 

 

 

 

B

 

 

ADo

PBo

WA

 

 

 

 

 

 

 

PCO- 5

AD,

PA,

 

 

 

ADz

PAs

RESET

TIMEA

 

 

 

 

 

 

AD.

PAs

 

 

 

 

AD.

PA.

TIMER eLK

 

Lvcc !+5V)

 

AD.

PA.

TIMER OUT

 

Vss IOVI

 

ADa

PAz

 

 

 

 

 

 

 

AD,

PA,

 

 

 

 

 

v••

PAs

*: 8155/8155-2 = CE, 8156/8156-2 = CE

 

 

 

 

 

 

 

 

IllEL _ 1I0Il _ 5 NO RE1I'IJIISIIlITY FOR TI£ USE OF ANY CIlCUITRI OTi£R THAN CIIClml EMBODEO IN AN IllEL PRODUCT. NO IlTHDI CIlCUIT PATENT UCENSES ARE _10.

"IIIEL _lION. 1979

6-82"

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Image 225
Intel mcs-48 manual Enable, 8085A 8085A-2, 8155-2, 8156-2