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RE: [N8VEM-S100:575] S-100 8086 Up and Runing

Delighted to hear that Leon. Always a relief to have somebody else
independently get a board up and running in case I overlooked something.  K8
is tricky. It decides when the pWR* & pDBIN signals actually become active
on the bus. According to IEEE-696 they are only active AFTER pSync and
pSTVAL go inactive.  You can sometimes "help" I/O boards get a jump on
things if you let them out earlier (K2-3) and this run the bus at a slightly
higher speed (or fewer wait states).  However some boards may not tolerate

I have not played around with higher speed chips but I suspect you could
squeeze 10MHz - possibly 11MHz out of the board  by playing around with
things.  I have currently settled to 9MHz (2 I/O wait states) which is
definitely stable with a 22 slot (Godboud active terminated motherboard).
Be sure to place the CPU card in the middle of the bus and the 4MG Static
RAM card at least 4 slots away.

BTW, you might want to cover the windows  on the EPROMS. UV light from
sunlight will eventually eat into them.


John Monahan Ph.D

-----Original Message-----
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
Behalf Of Elsid
Sent: Monday, December 26, 2011 2:43 AM
To: N8VEM-S100
Subject: [N8VEM-S100:575] S-100 8086 Up and Runing

Hi and Seasons Greatings.
All the best to everyone and their families.

I've just completed my S-100 8086 board.
See photos at:
Everything went smoothly except a missing K8 jumper 1-2 gave me some grief
for a while.
I have a V30 CPU and a 24MHz oscillator (8MHz clock) without any problems.
I'll try  10MHz next when I get a crystal.
Next step is to get CPM86 and MSDOS going.
Thanks for another great board John and Andrew.