Digi pot for pwm board

[mathphobe]

I did see page 7 kellys_eye, if I'm honest my minds eye couldn't see it as a circuit though. I'm in every sense a beginner to electronics and very much a visual kinda guy.

I'm not great interpreting the purpose of components on schematics dorke, there I see a shmitt trigger, a diode, an rc and another shmitt.. I assume it's all debounce related? Needs a a fair old sum of components there, wow! It just became a complex diy board etch for sure!
And to make one side of the resistor 10k it'll need passives in series with H & W? There's that horrid math stuff again

I see it needs a two stage switch and a selector switch? U/D high inc up, U/D low inc down and a pot select.. that's going to need some thought.
I'd had the bright idea to control it using a single 4 position smd navigation switch, up down for freq control and left right for duty, as ideally it needs to be a one handed operation. Simplicity usually works well but not so much in this case.

Plenty of food for though there guys, I'll go away and ponder on it a while

Thanks again for the assist!

 

[dorke]

The PWM duty cycle POT. works as a voltage ratio divider to set the duty cycle.
So it can be 100K instead of 10k (there is no limit for it ,only regarding leakage currents) ,
it will work fine,no need to change anything simply replace it from 10k to 100k.

Yes,
the Schmidt and stuff has to do with creating a de-bounced ,active low mono-stable pulse.
Switches are like you described as well.

You did talk about "a circuit for testing".
I would not recommend this circuit to be an "out of lab operational product".
I wouldn't attach, it only "wire it" on a 0.1" spaced board.
To change the frequency over the full range you actually need to press the push-button 256 times.
And another 256 times for the duty cycle change!
That is very cumbersome and tedious.

If you need a handy and operational product you should use a uC to control it.
it should not be an Arduino ,can be a simple "bare" uC with SPI or I2C they can be tiny.