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jgarff / rpi_ws281x

Userspace Raspberry Pi PWM library for WS281X LEDs
BSD 2-Clause "Simplified" License
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PCM on GPIO 21 not working #368

Open Jonah-Hansen opened 5 years ago

Jonah-Hansen commented 5 years ago

I'm working on a large scale project with 3844 total leds on sk6812 strips. using this library, I've been able to address up to about 2700 of them using GPIO 18 with PWM , but I was hoping to be able to use PCM and be able to light all of them.

Using a test strand of about 60 leds I've been playing around with trying to get them to work on GPIO 21 but i have yet to even see them light up. GPIO 18 works fine.

some more info: using a raspberry pi 3 B+ that boots into rasbian jesse using the guide here as I read in another issue that pcm doesn't work on stretch. (I had also tried it on stretch with no results)

Am I doing something wrong, or is there a better way to do this maybe? I would consider trying to use SPI if it can also handle the number of leds.

Gadgetoid commented 4 years ago

It's been a while since you raised this issue- have you had any luck since?

I'm afraid I don't know offhand why PCM would fail on BCM 21 - did you have an oscilloscope handy to verify that anything was being output on this pin?