DEC 3000 (alpha) faultfinding

[Peter Coghlan]

>
> On the AXPpci33 board, the SROM is also an 8 bit device. What happens is
> that the CPU reads in a bit stream into cache at power up reset, where the
> specific bit stream is selected by the jumper position on the board. In
> effect the SROM can contain up to 8 bit streams. Some of them will make use
> of the SROM console port.
>

Thanks.  The light bulb has gone on over my head at last!  Each of the 8 bits
in the EPROM is a separate serial data stream.  My ohmmeter confirms that the
data out pins on the 27C512 EPROM are connected directly to one side of the
bank of jumpers J1-J8.

In light of this, I've tried making sense of the EPROM data again but I still
don't see any ASCII strings (like "SROM" or "Powerup Sequence" for example)
jumping out at me.  Maybe the word size in the serial streams is not a multiple
of 8 bits or something odd like that or maybe I'm just making a mess of
assembling the bitstreams.

Regards,
Peter Coghlan.