Re: Clone IOU / MMU Chip

[aiiadict@gmail.com]

the IOU and MMU are custom logic chips that
select different circuits depending on address
inputs...

input: a0-a15

output: select1-X

select1 = i/o select slot1
select2 = i/o select slot2
select3 = i/o select slot3
select4 = i/o select slot4
select5 = i/o select slot5
select6 = i/o select slot6
select7 = i/o select slot7


address = a0-a15

if address HIGH = C1
   then select1=low (normally high, active low... see
http://osites.tripod.com/peripheral.html

if address HIGH = C2
   then select2=low

if address HIGH = C3
   then select3=low

if address HIGH = C4
   then select4=low

if address HIGH = C5
   then select5=low

if address HIGH = C6
   then select6=low

if address HIGH = C7
   then select7=low



also has ram row/column logic, selects
appropriate ram chip according to address
on bus..

what else?

Rich