9 Sep
2014
9 Sep
'14
3:04 p.m.
On Sep 9, 2014, at 1:48 PM, Yvan Janssens <ik at yvanj.me> wrote:
Do you know the "load address" from the ROM
in the 3com card? I know that
my ROM had a load address of c800, which is pretty common for HDD
controller cards, but the code you have might be loaded at the wrong
address.
Moved the jumpers to put the ROM at C8000, and now when it boots I get a lot of beeping
which sounds like typical PC error beeps, but then it boots from the disk drive like
normal. Searching around to try to figure out what the deal is on the 3c503 ROM socket, I
did find this on the etherboot wiki page:
In one case that we know of, the 3c503 network card, the ASIC
actually returns 2 bytes of 80 80 in the end locations of the
EPROM space.
Got into BASIC on the PC, and sure enough, at 0x1FFE and 0x1FFF there are two 0x80 bytes.
Plus reading past that is only 0xFF. Odd. The socket is a 28 pin socket so it needs at
least a 27128, yet it only passes through the first 8k? I can switch to the 8k XTIDE, but
I'm guessing I will need to do something about the two 0x80 bytes and recalculating
the checksum inside the ROM.
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