Servicing Personal Computers, 3rd Edition

44 Servicing Personal Computers

AO-

Al-

A2-

A3-

A4-

A5-

A6-

A7-

A8-

A9-

A10-

All-

CE-

Address

decoder

Memory

cell

matrix

4096

x

8

Output

data

buffers

Figure 1.46. 2732 simplified internal arrangement

A7C

A6d

A5C

A4C

A3C

A2C

AlC

AOC

DOC

DIE

D2C

ove

1· ^ 24

12 13

H+5V

DA8

HA9

I] All

HOE

DAIO

JCË

DD7

HD6

HD5

DD4

Ώ D3

Figure 1.47

2732 pin connections

Practical ROM arrangements

A typical arrangement of the read only memory in a 64K personal computer is shown in Figure

1.48. Three separate ROMs are provided, all three being mask programmed types. IC1

contains an 8K BASIC interpreter, IC2 (8K) contams the operating system kernel, and IC3 (4K)

contains the displa ...