My mistake was not to have disabled the interrupts from the system VIA. Although I start with an SEI, the various PLP instructions will sometimes perform an implicit CLI.
Cheers
Ed
To get diagnostics in the absence of a monitor, I changed all the self-looping traps to macro calls. In my case I write out the (stacked) PC to the UART, but writing to screen RAM would be another approach.
Code: Select all
fail macro
jsr printPCandStop
endm
failbne macro
beq skip\?
fail
skip\?
endm
failbeq macro
bne skip\?
fail
skip\?
endm