More Bringing up a CPM

From: Richard Erlacher <edick_at_idcomm.com>
Date: Tue Jun 1 20:07:49 1999

Well . . . If I were in your position, and I am, sort-of, I'd have my 'scope
out and be looking at the bus cycles and the memory cycles. If the DMAC on
the FDC generates cycles similar to those generated by the CPU, then you're
in good shape, since you then have only to make the DRAM board work with one
and it will probably work with both.

It's been a long time since I looked at S-100 hardware and I'm just now
starting to put some boxes up in order to verify functionality of some of
the dozens and dozens of boards sitting around. Since I have several of
each, in many cases, I just need to figure out an appropriate way to test
each one and then go through the set. For debug purposes, I may generate a
PROM for each debug function I need. Firs, however, I have to haul that big
Integrand box with the 8" Winchester out onto the patio and set a terninal
on top of it.

Even if you don't intend to use PROMs in your final device, I'd certainly
recommend you build a few PROMS which make the processor do rudimentary
things and perhaps which make the DMAC do the same things. You then have
simple tools with which to troubleshoot your memory interfaces.

After reading about the problems you're having, I think I'll fetch the 1240
LA out onto the patio as well.

Dick

-----Original Message-----
From: Dwight Elvey <elvey_at_hal.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Tuesday, June 01, 1999 6:43 PM
Subject: Re[4]: More Bringing up a CPM


>"Richard Erlacher" <edick_at_idcomm.com> wrote:
>> Is there a monitor that can be run to do things like run a software loop
>> to
>> write to, and subsequently, read from a block of SRAM? Does that work?
>> If
>> you're having doubts about the memory, it might be a good idea to leave
>> the
>> DMA out of things for a while, at least until your confidence in your
>> memories, of whichever type you decide to use, gets to where you have
>> some.
>
> Hi
> Leaving out the DMA isn't an option for doing CPM on this
>setup. It is the only disk access the mechine has.
>
> I will do some RAM testing tonight. This may be the problem.
>Like I said, I'll most likely do a March C since it is
>fast and I can include a larger address than would be
>practical with GALPAT.
>Thanks
>Dwight
>
Received on Tue Jun 01 1999 - 20:07:49 BST