Hi Rob,
>Slot #4: Mockingboard failed test: 6522
I can't fully explain this failure: perhaps an issue with the card (which is what it's designed to detect), or a bug in my code.
It's interesting that on your 2nd run (via entrypoint $2004 - but same 6522-test codepath) it succeeds this basic 6522 test.
If possible, can you retry by power-cycling and running the same tests (CALL 8192, then CALL 8196) to see if you can repeat this 6522 test failure?
>When I run the 2nd entry point, I get:
>Slot #4: NMI: 6522A=0 6522B=1 SC01=0 AY=0
OK, so the 6522A (at $C400) doesn't generate NMI, nor does the SC01 (which is connected to that 6522A VIA).
Only the 6522B (at $C480, with the AY8913 attached) generates an NMI.
And "AY=0" means that it can't read the AY regs for the 6522/AY8913 located at $C480.
I was expecting "AY=2" (it's a bitmask, so "2" means it can write, then read AY8913 regs at $Cn80).
This is a bit of a shame, as it limits the real h/w testing that can be done from code... and this works for the newer Mockingboard-C variants.
Although if there is a h/w issue (as suggested above) then this may explain why the AY8913 can't be written/read back.
Thanks.
Tom