[sebhc] H-89 bus pin out Help

Dwight Elvey dwight.elvey at amd.com
Tue Mar 14 12:24:25 CST 2006

 I don't think the pins you've labled are correct. As I recall
only A0, A1, A2 and maybe A3 were on the I/O buss.
The mother board decoded a number of blocks to the I/O
boards on some of the other pins. I don't think the
entire address were there through A12. Pin11 is the
select line for the floppy block of I/O.
 Also, I think pin 6 is BRD_L and 7 is BWR_L not address
lines. Pin 13 is the clock line ( 2.048MHZ ).

>From: "Joe Smith" <bandit1921 at cox.net>
>Here is a little text file from what I see on my Schematic, if you 
>look at the H17 Floppy connectors and the serial I/O connectors it 
>says different things,this is a combo of those and what it shows for 
>them on the CPU board.
>At 04:53 PM 3/14/2006 +0000, you wrote:
>>Bill Malcolm wrote:
>>>Hi: All I did not see the H-89 BUS Pin out in the archive files  ( 
>>>for the slot card).
>>The schematic for the floppy controller only identifies the pins 
>>that it uses, but it might be enough.
>>It doesn't look like we have the schematic pull-outs for the H88/89 
>>manuals in there yet.  I'll keep an eye out for some during my cleanup.
>>-- Steven
>>Delivered by the SEBHC Mailing List
>Joe Smith
>Conbuilder debugger /Programmer

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