Scanning encoder debounce on new scope

[Ioannis]

I might still go for that. But I'd really like to avoid any debounce on the PICs so they are free to USART with the main USB PIC.

This can work just fine:

1. Set up a timer interrupt at 10ms. Or even at 1ms and after ten int's do step 2.

2. Every interrupt read the buttons into the arrays. You can use a low priority interrupt if the PIC supports it.

3. Either with or without interrupt use the hardware USART to communicate. If you choose interrupt driven USART, use it as high priority, or Disable as long as you do serial, the timer interrupt.

Problem solved.

Ioannis

[Demon]

I wanted to see just how sharp a Schmitt trigger could clean up a signal.

This is using a MR0102 with rocker actuator, followed by the Bourns RC debounce circuit, and then inverted with a TCC74HC14 Schmitt trigger, followed by LED/330R resistor:



(text on image has been corrected)


Datasheet says negative threshold is 1.6V at 4.5V. This is USB 5V, so 1.8-1.9V seems ok to me.

[Ioannis]

What a magic tool Oscilloscope is, right?

Ioannis

[Demon]

Darn tootin' right.

It's nice to finally use it as a diagnostic/testing tool. The scope has always been a mystery to me. I've always wanted to use one, but never had any electronics training. So it's slow; getting old and a worsening memory doesn't help, but help from you folk make it fun.

One thing is for sure, I wouldn't hire me to do this stuff.

[HenrikOlsson]

Your waveforms seem to indicate that you might benefit from adjusting the trimmer capacitor on your probe(s).

[Demon]

Your waveforms seem to indicate that you might benefit from adjusting the trimmer capacitor on your probe(s).

I noticed that "rhythmic pulse" too. I figured it might be the breadboard.

I wanted to enjoy my scope for a few days before tweaking it and messing it up.
😄

[HenrikOlsson]

OK, if you just want to see squiggly lines on the screen :-)
But you're not going to mess it up. It's part of verifying that it actually works as it should.
Compensating the probe, or at least veryfying its compensation, should ideally be done whenever you move a probe from one channel to another - which is another great reason to use the color coded rings on the probes so that the same probe gets used on the same channel each time.

Without a properly compensated probe your scope will not display a "true" representation of the waveform and things like automatic risetime and peak-to-peak voltage measurements might be incorect.

I'm sure there's a section, close to the beginning, in the manual on how to perform the probe compensation.