11 Mar
1998
11 Mar
'98
3:30 a.m.
At 11:24 PM 3/10/98 +0000, you wrote:
Hey, you did RTFB!
Joe :-)
so I'd put that chip before
<> More recently, Intel designed the 8089 I/O co-processor as part
<> of the 8086 family. It had an instruction set optimized for I/O
<> functions.
And not so recently starting with the AT and all after the keyboard
interface chip is a slave cpu (8041a or 8042).
Well, my 8089 data sheet is copyright 1980, the PC/AT. This chip was used as the DMA controller in
the original
Apricot PC, BTW.
The 8089 is really a very fancy DMA controller with a limited processing
ability as well. There are AND/OR/NOT/ADD instructions (although no XOR,
no SUB and no shifts/rotates). It looks to have been a pretty nice chip -
pity it never caught on. It's a lot nicer than the 8237 + page register
kludge used on the PC.
Allison
-tony