Re: Atari AVG 137179-001 chip operation info needed

Actually, he did so privately, sent me the schematic for his board which is
based on Jed Margolin's schematic, save for some reduction of component
count by replacement simple logic gates with a single PAL chip. No need to
post scans of the PCB but thanks just the same. I have routed the same
circuit myself in the past but rather than manufacture them, I went ahead
designed a new one using the single Xilinx CPLD chip. I had this new PCB
manufactured and I populated 50 of them. I wrote the VHDL code some time
ago and was finally getting around to debugging it. During this phase, I
felt more comfortable about testing the Xilinx module using a homemade chip
tester, the one that I described earlier. To verify operation of the
tester, I plugged in known good original AVG chips. I was making very good
progress until I got to the part where the JSR/RTS instructions failed to
save/restore data to/from the stack memory. I'm 100% sure that the
equivelent logic circuit would have worked perfectly with the tester as the
logic analyzer shows the control signal waveforms to be ideal. So why
doesn't a real AVG chip work? I don't know yet but I'm working on it.

William Boucher
http://www.biltronix.com

----- Original Message -----
From: <litterbox99@mchsi.com>
To: <vectorlist@vectorlist.org>
Sent: Wednesday, November 02, 2011 8:18 PM
Subject: Re: VECTOR: Atari AVG 137179-001 chip operation info needed

> I'm surprised Clay hasn't chimed in...
>
> I have two of his 13179-001 replacement PCB's
> in front of me (dated 12-2-99 serial # 5 & 6)
>
> I can post some scans of the board if needed.
>
> Todd
>
>
> ----- Original Message -----
> From: "Jess Askey" <jess@askey.org>
> To: vectorlist@vectorlist.org
> Sent: Wednesday, November 2, 2011 5:54:18 PM GMT -06:00 Central America
> Subject: Re: VECTOR: Atari AVG 137179-001 chip operation info needed
>
> The Tempest schematic has a good representation of it but I believe the
> IC has more RAM for a deeper stack. Here were the notes I made of the
> whole shebang back in the 90's with an update in 2004...
>
> http://gamearchive.askey.org/Video_Games/Stuff/text/avg.txt
>
> not sure if that helps at all either.
>
> jess
>
> On 11/2/2011 5:37 PM, William Boucher wrote:
>> Thanks for the link, I found the AVG.pdf file. Very interesting
>> information there. It mainly pertains to how the AVG instructions
>> relate to game operation. There's not much there with respect to how
>> the circuit itself actually works, but I still have to go over the
>> state machine drawing and the opcode listing. It appears that it had
>> several more than just 4 functions. Again, thanks for that, more than
>> likely very useful stuff.
>>
>>
>> William Boucher
>> http://www.biltronix.com
>>
>> ----- Original Message ----- From: "Tom McClintock" <tomm@bhpllc.com>
>> To: <vectorlist@vectorlist.org>
>> Sent: Wednesday, November 02, 2011 6:35 PM
>> Subject: Re: VECTOR: Atari AVG 137179-001 chip operation info needed
>>
>>
>>> Andy got them from the Ireland plant and posted them at some point.
>>> I've got them here:
>>>
>>> http://ionpool.net/arcade/atari_docs/atari_docs.html
>>>
>>>
>>>
>>> On 11/2/2011 4:29 PM, Pat Danis wrote:
>>>> There is a link (somewhere) that is in handwritten notes on how the AVG
>>>> works etc. I am not sure if that is in Jed's pages or elsewhere. It is
>>>> rather obscure and I am not sure if I have a copy on my computer or
>>>> not.
>>>> I shall see what I can find.
>>>>
>>>> Pat
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Received on Thu Nov 3 00:02:49 2011