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The Atom needs some non-volatile random access storage. I ran out of
suitable patience burning EPROMs when updating the firmware for the new
MMC board. The old firmware was developed with the aid of an MMC
simulation that I shoehorned into the MESS emulator.
The simulator allowed me to code against a just-accurate-enough model
of an MMC card in SPI mode. The new interface doesn't have such a luxury
yet. So I got thinking, and decided that the 32kx8 FRAMs that I got
from Ramtron recently would do as an EPROM replacement. But I'd still need the
firmware in EPROM available to bootstrap from... Hmm. I'd also been
meaning to build a copy of a neat videoram replacement card that I found
in an Atom belonging to a friend. So that was that, really. Or rather,
At the moment it's only the video ram replacement side of the equation.
The flying lead takes A10,11,12 from the main board. The rest of the
signals are picked up from the vacated 2114 sockets. The empty socket is
going to take the FRAM and some decoding logic will live adjacent,
unless I can find suitable signals to pick up from the motherboard.
Not all underbellies are soft; This was quite hard, actually:
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