I've been working on a rewritable ROM board that connects to expansion port to boot code from there at $000000 when CART isn't grounded, of course.
I finally finisehd it, but it doesn't work. I connected two flash roms in parallel (8 data bits from one, 8 bits from the other), using the same adreess bus and strobes. I use /CAS_0 for /OE and /ROM for /CE.
I went through all joints twice.. I see no errors.
I tested a rom made in C (64Kb size), that has the starting code, as my Genesis has BIOS that checks that thing. Nothing either.
It really confuses me, why a ROM at $000000 does not boot from expansion port when /CART isn't grounded... I suppose it should work for the info I have and read here. All address lines are held high (I think, as I only used a multimeter), so the strobes. It's like freeze.
Any ideas?
I finally finisehd it, but it doesn't work. I connected two flash roms in parallel (8 data bits from one, 8 bits from the other), using the same adreess bus and strobes. I use /CAS_0 for /OE and /ROM for /CE.
I went through all joints twice.. I see no errors.
I tested a rom made in C (64Kb size), that has the starting code, as my Genesis has BIOS that checks that thing. Nothing either.
It really confuses me, why a ROM at $000000 does not boot from expansion port when /CART isn't grounded... I suppose it should work for the info I have and read here. All address lines are held high (I think, as I only used a multimeter), so the strobes. It's like freeze.
Any ideas?