Learning to 'scope with Multicomp

RE: Learning to 'scope with Multicomp

DAB — Tue, 22 Mar 2022 18:55:09 GMT

An oscilloscope can be lots of fun, as is the world of analog devices.

There is a much larger world out there than just ones and zeros.

RE: Learning to 'scope with Multicomp

baldengineer — Tue, 22 Mar 2022 15:33:30 GMT

> I haven't had any luck trying to scope fading with analogWrite, and I don't know if that's a limitation with the scope or with the user.

It depends on how fast you change the analogWrite() value in code. If you put the analogWrite into a loop, across multiple triggers you should see the pulse width changing.

[embed:dc8ab71f-3b98-42d9-b0f6-e21e02a0f8e2:2e9590d0-7272-42cd-ac96-8c069e6a4968:type=c_cpp&text=for%20%28int%20x%3D0%3B%20x%3C255%3B%20x%2B%2B%29%20%7B%0D%0A%20%20analogWrite%289%2Cx%29%3B%0D%0A%20%20delay%281%29%3B%20%2F%2F%20see%20difference%20with%20and%20without%0D%0A%7D]

With the 1 millisecond delay, you'll never see the PWM change on the screen (in a single acquisition.) Without, you *might* catch it. Either way, you'll see the pulse width change as the scope re-triggers.

RE: Learning to 'scope with Multicomp

Jan Cumps — Mon, 21 Mar 2022 06:15:31 GMT

> haven't had any luck trying to scope fading with analogWrite

You should see the high part of the signal go narrower and broader, when the analogWrite() vallue changes. The PWM frequency stays the same.

RE: Learning to 'scope with Multicomp

aspork42 — Sun, 20 Mar 2022 16:47:30 GMT

Awesome! Looks like a cool scope!

RE: Learning to 'scope with Multicomp

baldengineer — Sun, 20 Mar 2022 01:41:09 GMT

Heads up, pin 13 does NOT support analogWrite(). If you go peer inside of the function's code (line 276), you'll find that on non-PWM pins, it just turns the pin ON or OFF based on the value you passed. As you found out, Pin 9 does support analogWrite()! (Look at the silkscreen for the pins. Any pin with a ~ character supports PWM.)

Also, I'm glad the tutorials helped. I really hoped people would be able to see examples of real measurements they could make, regardless of the scope they have!