AlphaStation 200 NVRAM Problem
robert.jarratt at ntlworld.com
Sat Apr 23 09:26:22 CDT 2016
> Information on using that is however scarce and scattered, you can find
> some here to start: <http://labs.hoffmanlabs.com/node/1286> and then the
> pinout for the serial diagnostic port is included here:
> (the boot sequence is also described here, so you'll know that an NVRAM
> failure is reported by DROM code, i.e. before the final SRM or ARC console
> takes over and is able to use the regular serial port).
Indeed, I don't get any output on the standard serial port.
> That's a bit cryptic, but knowing that this is a low-level CPU interface
> gather the wiring from this document:
> So BSROMCLK is Tx and SROMCDAT is Rx, but as noted here and in the
> discussion in the first reference you need an EIA/TIA 232 driver and
> (there is power available on the diagnostic port, so you can use it for
> circuit), and of course you need to cross the lines wiring them to your
I don't think the SROM diagnostics are going to help much because the
failure is in the DROM sequence, which comes after the SROM.
> Finally the SROM console command reference is here:
> This manual doesn't specifically cover the Avanti, but I'd expect the user
> interface to be similar -- it's a low-level tool close to the CPU after
> NB on Avanti the 8kB NVRAM is separate from the TOY/NVR chip (which is a
> Benchmarq BQ4285, providing 114B of general storage only).
I had already located the Benchmarq chip and found the spec to be
insufficient for the 8K NVRAM. The problem is, I don't know which chip has
the NVRAM, I have not been able to locate it and the manuals don't tell me.
I hope it isn't one of the ASICs. I have posted a photo of the board here:
http://bit.ly/1qHQnaB in case anyone can id the NVRAM.
If the NVRAM contents are maintained by the battery then there should be a
way to reset the NVRAM contents, but there does not seem to be a way. I
wonder if the NVRAM persists without power? The manual seems to say that the
TOY is battery backed, but makes no mention of the NVRAM needing the
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