Hi Gert, I wanted to report that I am getting zero visible dot crawl using this timing on a Pi4 with a 15kHz Sony CRT monitor:Gert van Loo wrote: ↑Tue Oct 08, 2019 6:25 pmI don't know. Maybe they use a different drive strength for the GPIO or the Pi4 PCB has the tracks thinner and closer together. It can also be that there is more or different frequency noise on the supply. To trace things like this I would connect my spectrum analyzer to the signal and see if that show up anything different between the builds & PCB's.If this is a hardware-related problem, why does it happen only on Raspbian Buster and/or RPi 4, and not on Raspbian Stretch / RPi 3?
320 1 16 30 34 240 1 2 3 22 0 0 0 60 0 6400000 1
I was playing around with timings because I'm trying to get various old dos programs to work in dosbox, but other timings showed dotcrawl. I think it may be a sweet-spot kind of situation with the pulse width and placement and not necessarily an issue with the sync voltage level. But, hey, I could be wrong.