Or... Here's a completely different possibility:
Have you tested or verified the presence of "anti-corruption capacitor" (my
words) C94?
This cap "...maintains E2PROM data integrity..." "...during power-up or
power-down...", quoting Xircor.
It would be interesting to get a measurement on this cap, as it could
potentially explain a lot of "flaky" NVRAM behavior in SW boards.
HTH
-Mark
On Tue, Feb 22, 2011 at 9:38 AM, Jess Askey <jess@askey.org> wrote:
> So if switching to ESB during power off does it then the only things I can
> think of would be that SW is actually getting corrupted while ESB is writing
> to the NVRAM. So... try this...
>
> a. Do what Joel suggested first
>
> 1. put in SW mode... put up a high score.
> 2. Power Down.... remove the SW NVRAM (on Clay's PCB if I read that right)
> 3. Switch to ESB... turn on game
> 4. Put up an ESB high score
> 5. Power down... replace the SW NVRAM
> 6. Switch to SW (don't forget this or you will have to start over)
> 7. Bring up SW and data should be good still.
>
> So, with that, like Joel said on his check, you can see if it is chip
> specific then you can see if there is something funky in my process. If my
> process works and SW memory is still OK, then there must be something going
> on with the chip select between the two NVRAMs which is letting ESB write
> data to the SW NVRAM... when SW is powered back on and the data isn't
> checksumming correctly, it will restore it to DIP settings and overwrite it.
> If the memory in SW is still corrupt after this process, then it has
> something to do with the powerdown with the select switch being in different
> positions.
>
> ??
>
> jess
>
>
>
>
> On 2/22/2011 8:22 AM, Joel Rosenzweig wrote:
>
>> It would be worth swapping the two 2212 chips between SW and ESB to see if
>> the failure moves with the chip or stays with the socket. If it moves with
>> the chip then that's one debug path. If it stays with the socket then that's
>> a different one.
>>
>> Joel
>>
>> Sent from my iPhone
>>
>> On Feb 21, 2011, at 11:56 PM, "Altan (altan@aol.com)"<altan@aol.com>
>> wrote:
>>
>> Well, I think the reason this is hard to figure out is because the
>>> behavior is just plain screwy.
>>>
>>> I replaced the SW 2212 a couple days ago and it definitely started
>>> storing settings.
>>> For several days, it would power up with free play and my settings.
>>> About 4 hours ago, I got a high score (yeah! ... #3). I turned the game
>>> off.
>>> I just turned it back on and the settings were lost (as well as the high
>>> score). Boo!
>>>
>>> So we can most likely conclude from this that switching from ESB to SW
>>> isn't the root cause. Maybe I was just unlucky that the failure occurred at
>>> those times --- leading me to assume they were correlated.
>>>
>>> What's odd is that the novram test passes. FWIW, the novram test also
>>> passed with the original 2212.
>>>
>>> What does that tell us when the novram test passes? Anyone know what
>>> Atari actually did for the novram test? Did they write a pattern into the
>>> ram and then tell the chip to store it, then clear the pattern from ram and
>>> then ask the chip to restore it from novram? I'm wondering if knowing why
>>> the novram test passes might help explain what I'm seeing.
>>>
>>> Thanks again to everyone is hash chimed in --- or will do so :)
>>>
>>> ... Altan
>>>
>>>
>>> On Feb 21, 2011, at 11:46 PM, Altan (GAPAS) wrote:
>>>
>>> Joel, you have it correct.
>>>>
>>>> SW saves fine.
>>>> ESB saves fine.
>>>> Switch from ESB to SW (with power off) and SW loses settings
>>>>
>>>> ... Altan
>>>>
>>>> On Feb 21, 2011, at 11:40 PM, Joel Rosenzweig wrote:
>>>>
>>>> If the timing was wrong, wouldn't it fail to save the score in that
>>>>> 2212 all the time? I thought he said that SW saved the scores now, but,
>>>>> when switching back from ESB, SW was re-initialized.
>>>>>
>>>>> Maybe I'm misreading him again.. don't know.
>>>>>
>>>>> Joel
>>>>>
>>>>>
>>>>>
>>>>> On Feb 21, 2011, at 11:33 PM, Jess Askey wrote:
>>>>>
>>>>> I did lots of fanagling with the NVRAM on my I,Robot when it had
>>>>>> trouble saving settings and indeed, Atari seemed to balance the /SAVE line
>>>>>> with the timing of the +5V NVRAM supply *just right* to make the NVRAM save
>>>>>> data right before power disappeared. Technically, if you doubled the load,
>>>>>> the power supply would drop in about half the time so putting a big cap in
>>>>>> parallel with C93 seems like the best bet... at least to eliminate that
>>>>>> possibility.
>>>>>>
>>>>>> On 2/21/2011 8:42 PM, Clay Cowgill wrote:
>>>>>>
>>>>>>> I'm assuming this is the 2212 used for SW novram. Is that right?
>>>>>>>>
>>>>>>> I'm 99% sure that's right. (Sorry, it's been a long time since I had
>>>>>>> to
>>>>>>> look at/think about that. ;-)
>>>>>>>
>>>>>>> The idea was that you could take your existing Star Wars settings and
>>>>>>> high
>>>>>>> scores and move them over to the daughterboard without losing
>>>>>>> anything.
>>>>>>>
>>>>>>> The only thing that comes to (my) mind at the moment is that maybe
>>>>>>> with two
>>>>>>> NOVRAMs sharing their connections (except for the chip select which
>>>>>>> is muxed
>>>>>>> by the game select switch) maybe the 'new' SW 2212 doesn't have
>>>>>>> enough time
>>>>>>> to store the SRAM copy of the memory to the NV portion of the chip
>>>>>>> before
>>>>>>> the EAROM power goes away.
>>>>>>>
>>>>>>> For grins, you might try something like putting a big electrolytic
>>>>>>> cap
>>>>>>> across the "+5EAROM" power and ground pins of the 2212's on the
>>>>>>> daughterboard. (Like a 470-1000uF or something-- you could also put
>>>>>>> it in
>>>>>>> parallel with C93 on the SW board-- careful with the polarity.)
>>>>>>>
>>>>>>> -Clay
>>>>>>>
>>>>>>> P.S. My apologies to anyone contacting me in the last few months if
>>>>>>> I
>>>>>>> missed replying to you. We *just* finished getting Ground Kontrol
>>>>>>> back to
>>>>>>> our permanent location after a huge three month remodel, so it'll be
>>>>>>> several
>>>>>>> weeks still before I get my head above water again. We were doing
>>>>>>> 120+ hour
>>>>>>> weeks there towards the end. ;-)
>>>>>>>
>>>>>>>
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Received on Tue Feb 22 11:42:06 2011
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