I did following test.terriblefire wrote: ↑Tue Oct 20, 2020 9:58 am A simpler test would be to use diagrom to probe an area of RAM like B00000 ...
make the arm respond with the lower 5 bits address bits being sent.
that way you should see
00 01 02 03 04 05 06 07 08 .... up to 1F
then it repeats.
Decode like B000xx
ARM repeat address back on read. A[5:0]
When I decode 0xB000xx I see as follows But when I try the same trick on JOY0/1DATA I see this
Edit.
Is it some kind of clash with chipset?