Re: RASTER: FW: Using 8080 pod on Midway 8080 boards (Space Invaders)

David Shoemaker wrote:
> The pod has a -1 CPU in it which should be good to 3 mhz the board is a
> straight 8080a which should be 2mhz. But I tried it with the CPU from the
> board just for completeness. No improvement. And the pod cpu works fine in
> game.
>
> I have one board that will at least start up partially with the pod, but two
> others that just error on Run UUT.
>
> It is really inconsistent. I think the way the memory system works the fluke
> ram test will never work (strange timing and sync to get the game board
> rotation stuff to coordinate access to ram).
>
> I have two of these pods, both use the flat ribbon. I tried subbing a
> twisted ribbon from an 8085 pod but the pod fails self test (I suspect the
> ground lead is mucking with something).
>
>

I was testing an 8080 board only last year, but didn't get it booting,
so it is sitting waiting for me to take another go. I can't recall doing
the "Run" on any of the 8080 boards recently so haven't any better ideas
at the moment...

Perhaps someone else here has a suggestion?

John :-#)#
> -----Original Message-----
> From: techtoolslist-bounces@flippers.com
> [mailto:techtoolslist-bounces@flippers.com] On Behalf Of John Robertson
> Sent: Sunday, February 17, 2013 7:23 PM
> To: techtoolslist@flippers.com
> Subject: Re: [Techtoolslist] RASTER: FW: Using 8080 pod on Midway 8080
> boards (Space Invaders)
>
> David Shoemaker wrote:
>
>> So my mails to tech tools don't appear to be getting through. But this
>> is a raster game so I will cross the stream.
>>
>>
>>
>> *From:* David Shoemaker [mailto:davids@oz.net]
>> *Sent:* Saturday, February 16, 2013 12:20 AM
>> *To:* 'Technical Tools Mail List'
>> *Subject:* Using 8080 pod on Midway 8080 boards?
>>
>>
>>
>> I have a fully working space invaders board which when I hook the pod
>> up to and do Run UUT doesn't, it starts up and crashes.
>>
>>
>>
>> Pod passes self test.
>>
>>
>>
>> Anyone ever done this?
>>
>>
>>
>> David
>>
>>
> Try a faster 8080 CPU in the pod, or try substituting the 8080 from the game
> in place of the pod CPU. It is possible the CPU is bad or slower than the
> system can handle.
>
> Do you have the flat ribbon cable from the pod to the CPU socket or the
> twisted pair cable? The twisted pair cable handles noise better and will
> work in situations when the simple flat cable won't, plus it can be longer
> as a result.
>
> David, I have no idea why this did not show up in TTL - you are subscribed
> under the same email address as you posted here. I haven't seen any bounces
> for your email address.
>
> John :-#)#
>
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Received on Mon Feb 18 23:13:23 2013