search

frntc / SIDKick-pico

SIDKick pico is an inexpensive dual-SID-replacement for the C64 and C128
Other
205 stars 19 forks source link

Diagnostic reports control port bad. #32

Closed dotnbot closed 6 months ago

dotnbot commented 6 months ago

250407 mb C-64 Diagnostic REV586220++ using a harness. The Control port and thus the sid are indicated bad. I have tested it on 2 different SKP's. First one was assembled by PCBway, I built a second one.

They both sound great, I just find it strange they are failing the control port.

frntc commented 6 months ago

I think I know why it reports "bad" (although it isn't :-)). The harness uses a resistor to simulate a paddle at a fixed position. The way how the (minimalistic) level shifting on the SKpico works results in a reported potentiometer value that is a bit smaller than with an original SID (in mouse or paddle operation that does not matter). As the diagnostic code tests for the value to be within a certain range, it reports an error. Changing the resistor value or the diagnostic ROM would be one option, the other might be revision 2 of the hardware and firmware ;-) (but no promises that this particular issue will be addressed (immediately))