On 11/25/2021 5:57 PM, George wrote:
> Just to bring this to a conclusion, I've written alternative IRQ servicing
> code that bypasses the "BEQ" error in rom, and a BASIC program that
> installs the new code into the tape buffer.  It's 120 bytes of ML that does
> the ACIA processing and then jumps back into ROM for the rest of the IRQ
> routine.  The BASIC program and the source code for the ML portion are
> shown below. The actual .PRG file can be downloaded from my Github CBM
> repo:
>
> https://github.com/gbhug5a/My_CBM_stuff
>
> Since I no longer have a +4, I have no way to test the new code.

Do you have the VICE emulator?  It supports the +4 and the built in
6551, and can tie that 6551 ACIA to a real or virtual serial port.  You
could test it there if desired.

Jim

--- SoupGate-Win32 v1.05