Our debugging journey at VCFe began right at powering up the board the first time, when something got real hot real fast. Fair enough, and easy to spot. There was a mixup of VCC and GND at U29, a 74HCT244. Embarassing, but not that critical, as U29 is only used to connect the joystick ports to Port A of the VIA. We can live without them for now. The mixup likely happened when I transferred the IO-board schematics from KiCad 6 to 7 while updating the symbols from the current library, which happened to be different than the old ones.
Our plan for VCF2 22.0 was to assemble the first Steckschwein SBC right at our booth as some kind of show-cooking event. That only half worked, as this quickly turned into show-debugging instead of show-cooking. It was only just right before the end of VCFe 22.0, just before we had to pack everything up, we managed to get the SBC to talk to us via serial: It‘s alive. Sort of. pic.
Just in time for VCFe 22.0 our new SBC boards have arrived! Be there at VCFe, when we are assembling the new Steckschwein SBC and have a few beers with us! Save the date(s): 29.4. - 1.5.2023 ESV München OST, now at Hermann-Weinhauser-Straße 7 81673 München Check it out: https://vcfe.org/
Looks like the upcoming VCFe 22.0 will be a feast for the 6502-connoisseur: Andre Fachat will show his MicroPET and his 6502 multitasking operating system “GeckOS”, Armin Hierstetter will show an authentic Apple I replica, and of course we will be there, too, showing our new banking schema and our emulator. Save the date(s): 29.4. - 1.5.2023 We really are looking forward to a glorious VCFe, which will also be back at the new old location, the sports hall of the ESV München OST, now at
This one really is a tough one to debug. At first, we suspected the VHDL code for the CPLD as the main error source, as VHDL is not our strongest suit. In fact, the decoder/banking logic is the first thing we ever really did in VHDL (apart from a few simple decoder equations the first days we were playing with GALs). As it turned out, the VHDL was not the main problem.