[Techtoolslist] RASTER: FW: Using 8080 pod on Midway 8080 boards (Space Invaders)

[John Robertson]

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 at flippers.com

> [mailto:techtoolslist-bounces at flippers.com] On Behalf Of John Robertson

> Sent: Sunday, February 17, 2013 7:23 PM

> To: techtoolslist at 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 at 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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