Intel 8080 manual Dynamic Memory Refresh Controller

Models: 8080

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Schottky Bipolar 8222

DYNAMIC MEMORY

REFRESH CONTROLLER

Adjustable Refresh Request Oscillator

Ideal for 8107A, 81078 4K RAM Refresh

I nternal Address Multiplexer

Up to 6 Ro . (64x 64,t}'

'\ff

The 8222 is a refresh controller for dynamic RAMs requiring row ref.JJj"\:;;

W inR,~"addresses (or 4K bits for 64 x

,'<:i"~:/:, 0 ,

~ '~

64 organization). The device contains an accurate refresh timer (w~~)t::,~rL, ,"

'" n be,,-set by an external resistor and ca-

,:~\~'r',;":::--:, 0,<,:,,,:-,:<':).

,.:-~~

pacitor) plus all necessary control and I/O circuitry to provide ~~fi~~"'~\';ra~f'~t{sM'.'f~~uirem~ts of dynamic RAMs. The chip's high performance makes it especially suitable for use with hi9Q{(-'-~>~~":;;~~~b_,~~J;~RAIYl~1ikethe 81078. The 8222 is designed

for large, asynchronously driven, dynamic memory systems. ~~';;~~;~'~"!J;F~j») eft

PIN CONFIGURATION

 

BLOCK DIAGRAM

 

 

 

 

 

START CYCLE

 

 

CYC. REQ.

REFRESH

ACK

a

 

BUSY

REQUEST

REF. ON

 

LOGIC

REFREQ

 

 

 

 

CYREQ

 

 

 

 

STARTCY

 

 

 

 

ADDRESS INPUT A2

 

 

CENTER

 

ADDRESS INPUT A1

 

 

 

OUTPUT

 

 

 

 

ADDRESS INPUT Ao

A4 ADDRESS INPUT

 

MUX

ADDRESSES

 

Ao-As

 

 

INPUT

 

ADDRESS OUTPUT 00

As ADDRESS INPUT

 

 

ADDRESSES

 

 

ADDRESS OUTPUT 0 1

 

Vee

 

 

ADDRESS OUTPUT 02

04 ADDRESS OUTPUT

 

REF.

 

 

 

 

D

GROUND

03 ADDRESS OUTPUT

cX/Rxl---

REa.

 

 

osc.

 

 

 

 

 

I-=-

5-99

Page 165
Image 165
Intel 8080 manual Dynamic Memory Refresh Controller