Hello all,
I have a BeagleBone design I am working on, for interfacing with an external LED light array via the PWM outputs.
The current hardware has all of the LEDs sharing a common 3.3V power source, but the current default PWM setup is to output power to the PWM after the pins have been muxed.
I see that there is a Polarity attribute in the AM335x PWM Driver’s Guide, but I am not clear if that actually changes the current flow or just outputs 3.3V with the inverse waveform. I am thinking about jumpering a GPIO pin to provide the necessary shared 3.3V power between all of the LEDs, but I don’t want the magic smoke to escape from my BeagleBone so I thought I would ask the group first.
So to summarize, using for example a four conductor plug that has shared power, and with each conductor tied to a separate cathode on an LED:
- Does the Polarity attribute for the AM335x PWM allow current to flow in the opposite direction?
- If so, what are the dangers with jumpering a GPIO to pull 3.3V for that shared power? Should there be current limiting resistors in this design?
- What would the appropriate Angstrom filesystem command be to provide power via GPIO?
Thanks in advance