8212

VIII. 808SA Low-Order Address Latch

The 808SA microprocessor uses a multiplexed address/ data bus that contains the low order 8-bits of address information during the first part of a machine cycle. The same bus contains data at a later time in the cycle. An address latch enable (ALE) signal is provided by the 808SA to be used by the 8212 to latch the address so that it may be available through the whole machine cycle. Note: In this configuration, the MODE input is tied high, keeping the 8212'soutput buffers turned on at all times.

 

 

12

 

 

 

 

AD,

13

 

 

 

 

14

 

 

 

 

AD2

 

 

 

 

1S

 

 

 

/:AD3

 

 

 

16

..

 

DATA BUS

BOSSA

AD4

17

 

 

AD5

18

 

 

 

 

 

 

AD6

19

 

 

 

AD7

 

 

 

 

 

ALE ~

 

 

 

 

 

 

VJc

 

 

 

 

 

11

 

 

 

 

~DI, STBDO,&

 

 

 

5

 

~

 

 

 

7

 

8

 

 

 

9

 

~

LOW ORDER

 

 

16

 

~

 

 

18

8212

f-j7

ADDRESS BUS

 

 

20

 

r,g-

 

 

 

22

_

121:

 

 

 

f

CLR

1

 

 

 

" .';,j~

 

1 _

Vcc

8-29

AFN-00731 A-()6

Page 290
Image 290
Intel mcs-48 manual AD2, Bossa AD4 AD5 AD6 AD7, ~DI, Stbdo LOW Order, Clr