3 ms·

At 50 kHz, can you understand anything from looking at over 300 LEDs? Or is it just the impression that things are happening too fast? Which isn't really the ca

At 50 kHz, can you understand anything from looking at over 300 LEDs? Or is it just the impression that things are happening too fast? Which isn't really the case for 20 times slower than the original 1 MHz.

mdp2021 4y ago
Very surely loops should show a rhythmic pattern. I am sure I have seen equivalent project that run on the browser... Check e.g. Visual 6502 - http://www.visual6502.org/JSSim/index.html http://www.visual6502.org/JSSim/index.html
- jmole 4y ago
  Would be fun to watch this hardware alongside a sorting algorithm visualization like this: https://www.sortvisualizer.com/quicksort/ https://www.sortvisualizer.com/quicksort/
  - fsckboy 4y ago
    from back when computers had really small memory, I've seen software that did sorting on the user screen because the screen at that point was extra available free memory!
CodeWriter23 4y ago
At 1Mhz you could tell certain things, like looping or crashed by looking at the front panel of my Altair 8800.
- kazinator 4y ago
  Yes. Some years ago I was debugging a Z80 start-up problem (ADA MP-1 guitar pre-amp). By probing the address lines, I was able to deduce that it's in a tight loop. It turned out to be a dumb circuit design around the Z80's NMI. I don't remember the details now, but there is a circuit that is like a low voltage (brownout) detector that triggers NMI, where the firmware branches to a loop. The idea was likely this: to prevent trashing the settings if that happened during a write cycle (setting being stored). Anyway, this NMI would happen on startup, during the voltage ramp-up. I deduced it purely from reading the schematics that, hey, this circuit could activate NMI close to power up. The fix was to just cut the trace to the NMI line with a sharp instrument; presto, no more random lockups on power on. The kicker was having debugged all this, I found a 1989 dated document from Ada which confirmed everything and recommended the same fix. I think had that document all along but it was hard to understand what it was getting at. and take note, if you didn't already understand the problem.
tubetime 4y ago
at 50KHz, the LEDs mostly appear to be on, albeit at different brightness levels. but with the clock rate set much lower (say, below 50hz) it looks a lot more animated.
- deleted 4y ago
  [deleted]

mdp2021 4y ago

Very surely loops should show a rhythmic pattern. I am sure I have seen equivalent project that run on the browser... Check e.g. Visual 6502 - http://www.visual6502.org/JSSim/index.html http://www.visual6502.org/JSSim/index.html

jmole 4y ago
Would be fun to watch this hardware alongside a sorting algorithm visualization like this: https://www.sortvisualizer.com/quicksort/ https://www.sortvisualizer.com/quicksort/
- fsckboy 4y ago
  from back when computers had really small memory, I've seen software that did sorting on the user screen because the screen at that point was extra available free memory!

CodeWriter23 4y ago

At 1Mhz you could tell certain things, like looping or crashed by looking at the front panel of my Altair 8800.

kazinator 4y ago
Yes. Some years ago I was debugging a Z80 start-up problem (ADA MP-1 guitar pre-amp). By probing the address lines, I was able to deduce that it's in a tight loop. It turned out to be a dumb circuit design around the Z80's NMI. I don't remember the details now, but there is a circuit that is like a low voltage (brownout) detector that triggers NMI, where the firmware branches to a loop. The idea was likely this: to prevent trashing the settings if that happened during a write cycle (setting being stored). Anyway, this NMI would happen on startup, during the voltage ramp-up. I deduced it purely from reading the schematics that, hey, this circuit could activate NMI close to power up. The fix was to just cut the trace to the NMI line with a sharp instrument; presto, no more random lockups on power on. The kicker was having debugged all this, I found a 1989 dated document from Ada which confirmed everything and recommended the same fix. I think had that document all along but it was hard to understand what it was getting at. and take note, if you didn't already understand the problem.

tubetime 4y ago

at 50KHz, the LEDs mostly appear to be on, albeit at different brightness levels. but with the clock rate set much lower (say, below 50hz) it looks a lot more animated.

deleted 4y ago
[deleted]