On 11/27/23 11:48, runrin wrote:
Do you know if it's possible to dump the original ROM using the
programming adapter for the FlexROM 100?
Maybe.
There are two things to worry about and I'll just think out loud right here.
1
The programming adapter presents a pinout for a 28C256, not a 27C256 or
mask rom. Those are only a couple wires different, but then again, since
it's just for reading, and the read cycle is the same, you could just
tell the programmer that it's reading a 28C256 (force it, override chip
id detection), and that won't hurt the rom.
2
Pin 23. The programming adapter routes pin 27 from the programmer (/WE
if a 28C256 were in the programmer) to pin 23 of the DIP socket, which
is ALE on the LH535618 rom, but the flexrom board connects it to the /WE
pin on the actual 28C256 on the board.
I *think* what you want to do is take a DIP-28 socket and bend out pin
23, connect the bent-out pin 23 to pin 27, put the modified socket into
the programming adapter and then the old rom into the modified socket.
Then tell the programmer to read a 28C256 and ignore chip id. The socket
is just to avoid bending the leg on the old chip.
IE, feed /CE from the programmer to both /CE and ALE on the chip, and
don't connect anything to /WE at the programmer.
But, at that point it's almost simpler to just make the entire adapter
manually with two dip sockets and wires. Especially since it's a
one-off. In that case, use a 27C256 pinout and tell the programmer to
read a 27C256 instead of 28C256.
But if your chip has any of these part numbers, then it's already been
dumped.
https://bitchin100.com/wiki/index.php?title=Model_and_ROM_information
--
bkw
