Uploaded November 2019 | Updated September 2026, 1 week ago
I've bought myself an oscilloscope, this video is my first exploration of the cpu build testing a few assumptions and learning about the analogue side of things in the build.
Spoilers:
I find the master clock rises comparatively slowly, the 555 timer isn't a high speed logic part so I clean that up by passing it thru a couple of spare invertors. I also take the led display of separately as it's obvious that the led is effecting the line (No doubt I'll need to pay attention to this elsewhere).
I discover the clock to the bus control isn't delayed as much as I thought, I add a nice big delay there (I'll drop this down once things are stable again, I just wanted to completely eliminate it being an issue).
I find there is a noticeable amount of noise between the ground in the register stack and ground in the pipeline. I resolve it with a direct ground link, this appears to have completely resolved the superflous counting issue.
Finally I identify a 1 cycle long burst of noise which seems to be associated with the indirect memory reads, I'll leave that for future troubleshooting.
I've bought myself an oscilloscope, this video is my first exploration of the cpu build testing a few assumptions and learning about the analogue side of things in the build.
Spoilers:
I find the master clock rises comparatively slowly, the 555 timer isn't a high speed logic part so I clean that up by passing it thru a couple of spare invertors. I also take the led display of separately as it's obvious that the led is effecting the line (No doubt I'll need to pay attention to this elsewhere).
I discover the clock to the bus control isn't delayed as much as I thought, I add a nice big delay there (I'll drop this down once things are stable again, I just wanted to completely eliminate it being an issue).
I find there is a noticeable amount of noise between the ground in the register stack and ground in the pipeline. I resolve it with a direct ground link, this appears to have completely resolved the superflous counting issue.
Finally I identify a 1 cycle long burst of noise which seems to be associated with the indirect memory reads, I'll leave that for future troubleshooting.
