led pwm

[espruino-discuss]

Posted at 2016-12-07 by Drarok

Is appears that only one of the LEDs can be sent a PWM signal at once – the following will result in only LED2 being lit. Is this a hardware limitation? Can't find anything definitive.

analogWrite(LED1, 0.2);
analogWrite(LED2, 0.15);

[gfwilliams]

Posted at 2016-12-07 by @gfwilliams

At the moment it's a firmware issue that'll be solved in a later update - just one of the hardware PWMs is exposed at the moment.

You can easily work around it using software PWM with analogWrite(LED1, 0.2, {soft:true}); though, then you can run pretty much as many as you want (albeit at lower speeds).

[espruino-discuss]

Posted at 2016-12-07 by Drarok

I tried with soft: true and forceSoft: true and got weird results. Not important though, I'll try this again once the firmware is updated – I can just offset the LEDs for now and make sure only one is on at a time.

[gfwilliams]

Posted at 2016-12-07 by @gfwilliams

Looks like i was wrong about soft:true, but I just had a quick look and you can get something working with the following:

function t() {
  analogWrite(LED1,0.1+0.09*Math.sin(getTime()), {freq:100,forceSoft:true});
  analogWrite(LED2,0.1+0.09*Math.sin(getTime()*1.2324), {freq:100,forceSoft:true});
  analogWrite(LED3,0.1+0.09*Math.sin(getTime()*1.4634), {freq:100,forceSoft:true});
}
setInterval(t, 50);

Looks like there's a glitch with multiple soft PWM when you give some a value of 0 though (hence the 0.1+0.09*x).

[espruino-discuss]

Posted at 2016-12-07 by Drarok

Ah, I was getting bright flashes, presumably that's the zero glitch? Still seeing some weirdness with the above, but closer to what I was aiming for, thanks.

[gfwilliams]

Posted at 2016-12-21 by @gfwilliams

Just to add, the 1v90 firmware fixes this - making software PWM work better but also allowing you to use multiple hardware PWM channels - it means the original code should now work too.

[espruino-discuss]

Posted at 2016-12-23 by Drarok

Updated my Pucks last night and removed the forceSoft option, working absolutely perfectly now, thanks so much.

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