Yeah I think I got the serial working, however there's other problems. Like the various current draws when it shouldn't be doing much of anything in STBY. Sometimes the RAM gets active and pulls a lot more current, and the MCU/IC currents are not consistent, from 1 power up event, vs the next power up. I'm missing PCBs too, so who knows what the IC's are doing.
For a while, I'm not sure why, it was freezing up, while trying to display the start up message. On the day before it was doing that, when I 1st got some logic captures, the MISO line of the VFD IC hardly moved at all over the whole 20-25secs when the display is active.
Now since it's been freezing up, whatever part of the stuck message is on screen, it still stays lighting up, so I could easily see the bit sequence to the VFD pins, as +5/-20 anyways. And I have SPI captures too, and the same thing just gets repeated, but IDK what yet.
But now since it's been freezing up some, the MISO line is doing a lot of stuff. Some of which looks unplanned, like beeping high, in the middle of nowhere, with no clock running. Most of the time it doesn't look random tho.
But I did clean the VFD IC and all the pins I soldered stuff to again, and I did get it to fully run again, without freezing, and get a full capture with the correct SPI settings. But towards the end, the MISO line starts doing stuff again, a few days ago, it stayed low 99.9% of the time.
But yeah, I can only imagine what the bits are doing. And then what program and info are already is stored in the VFD IC ?
I'm just trying some more Arduino/ATmega328/C++ coding, so getting inside the maskROM of the VFD IC is over my head. They do explain a fair bit in the datasheet about the VFD setup, but yeah IDK enough ComputerSci to get it yet.
At some point I might try looking for patterns in the PulseView text file data, if I learn some more C++ or Phython, or try some freeware program.
Seems I can't upload the Pulseview file, and I'm not on any filesharing site.