Generating PWM Signals

[moelski]

Hi !
There is one thing missing in this Lib ... generating PWM signals.
At the Moment I see 3 different ways ....

1. Using the Hardware like in this lib: http://www.ofitselfso.com/RPICSIO/Help/RPICSIOHelp_PWMPortExample.html

    # enable one PWM with GPIO_18, header Pin12 by default
    dtoverlay=pwm.dtbo
    # enable two PWMs GPIO_18, header Pin12 and GPIO_19, header Pin35 by default
    dtoverlay=pwm-2chan.dtbo

2. Using Software PWM with Pigpiod as a service (can be accessed by TCP). I used that in some cases and it works really well.
3. Writing an own Software PWM class - but at the moment I have no idea how fast we can toggle Pins...

What do you think about generating PWM directly on the Pi ?

Dominik

[JTrotta]

We can try.
But I remember on old P1, PWM was very CPU expensive.
Now I'm using external chips, but we can try on new pis.
I do not have any preference; point 1 should be tested, point 2 do not know you can try , point 3 should be easy, we can toggle at 1ms.

[JTrotta]

Good news,
I'm going to implement the original bcm2835 PWM code. I will create a new folder like InterIntegratedCircuit that will contain all PWM driver code.
Stay tuned.

[moelski]

Hmm that means we will only have 2 Channels, correct ?
I will place my pigpio based code the next days as a PR.
Not the best solution, but itś ok for controlling Servos and Motors.

Dominik

[JTrotta]

Yes 2 channels gpio 18 and 19.
If we want more, we need external chip like TLC5940 or PCA9633.

[wezzix]

I was just looking for PWM functionality. Did you make it work?

[JTrotta]

@wezzix I did not do any test on PWM.