First program fully operational

A project log for GTXL Gigatron clone computer with keyboard

Microcomputer that runs without a CPU

Justin DavisJustin Davis 07/30/2019 at 20:080 Comments

Looks like the last solder fix did the job and the first program is now running fully.  I put the official ROM back in and I did not see the blinkenlights running like they are supposed to.  So I'm guessing there's more problems.  I've verified I can load the AC, Y, and PC registers with the correct data.  Next I think I will write a simple program to verify the blinkenlights since that's my check that the ROM is working.  That will verify the OUT register and XOUT register.  I supposed I could throw in an instruction to load X to verify the X registers are working right as well.  

After that I may start checking the ALU using the blinkenlights.  Since I'm single stepping through the program, I can see the lights fairly easily and it saves me from having to probe every pin on every device to verify the ALU output bus.  Kind of the purpose of blinkenlights, wouldn't you say?