RE: [N8VEM: 8655] Re: S-100 Motherboard

["Andrew Lynch" <lyn...@yahoo.com>]

> -----Original Message-----
> From: n8...@googlegroups.com [mailto:n8...@googlegroups.com] On Behalf Of
> RichLeary
> Sent: Saturday, February 19, 2011 5:49 PM
> To: N8VEM
> Subject: [N8VEM: 8655] Re: S-100 Motherboard
> 
> Andrew  & the group:
> 
> Some more testing today yielded some progress. I have now installed
> my
> floppy controller and the hard disk interface board on the
> motherboard. Neither is connected to drives.
> 
> 
> Good news is that the system still resets on power up and the basic
> monitor functions work.
> 
> 
> Next step will be to try booting CP/M after connecting the drives -
> very big step.
> 
> 
> I did run into a couple of issues today:
> 
> 
> a. First, the pin numbering on P2, P3, P4, & P5 on the motherboard is
> wrong as long as you think the square lands are pin 1 for each of
> these headers. If you assume the square lands are pin 2 then all is
> well.
> 

[AJL>] 

Hi Rich!  Thanks!  Yes, the pin 1 errors were fixed on the updated S-100
backplane revision.  This was an error on the original board and sorry for
the hassle.  With each revision the boards are getting better!

> 
> b. At first I could not get an external /PRESET to work. To make a
> long story short - the circuit was fine - I had a switch set wrong on
> the CPU-Z. The fascinating thing is that I don't think I changed it
> on
> purpose so that may explain some problems with my old system. It is
> working fine and testing also reveled that all I really need is a
> switch that will ground bus pin 75 to do a reset. No active circuitry
> is needed.
> 

[AJL>] 

Thanks!  That's great news!

> 
> Next steps are the toughest ones though.
> 
> 
> Rich
> 
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[AJL>] 

Wow!  I am looking forward to seeing your progress!  Please keep us posted!

Thanks and have a nice day!

Andrew Lynch