Reply 20 of 27, by alexanrs
Hum... my programmer got here, and so did the EEPROMs and the controller, but things are just not going well...
First of all, I built an AT2XT converter. Did not order the PCB, so I just breadboarded it like this:
And it works!!!!
But... for the rest:
1- The controller seems to be busted. It did not work when it arrived (neither in this board nor in a Pentium machine with the onboard FDD controller disabled). Today I put it on the 8088 PC again to test it one final time and BAM, my floppies were seeking and stuff was working.... until I turned the PC off and on again, then they went back to not working at all
2- The EEPROM doesn't work. It simply doesn't POST with the W27C257 in the socket.... Oh, it actually does POST if I flash the machine's regular BIOS (which I read from the 27128 BIOS chip) to the last 16KB of the W27C257 AND leave the original BIOS chip in its socket (it doesn't post if the EEPROM is there by itself) - and in all cases the Option ROMs are completly ignored. What sorcery is this? I imagine, from my results, that you are not supposed to have both EPROMs there at the same time, but why wouldn't it POST then with the W27C257 by itself?
Btw, I backed up the original BIOS and will update the first post accordingly.