PWM in Python without PWM Expansion?

[Jeff Verive]

Are there any Python libraries for outputting PWM signals on GPIO pins without having to use the PWM Expansion Module? I am controlling some LED light strings by GPIO pins (through a simple interface circuit), and would like to be able to vary brightness. I'm getting comfortable with Python programming on the Omega, and this would be a reasonable application for software PWM (doesn't require the precision of dedicated PWM hardware.

[Lazar Demin]

@Jeff-Verive Not that I know of, but you could potentially write one yourself that uses the sysfs gpio interface. Or you can make calls to fast-gpio from python.

I suspect that fast-gpio will be more accurate than a python implementation since it completely bypasses the sysfs gpio interface and controls the gpios via the AR9331s registers directly.

[Jeff Verive]

@Lazar-Demin,

Follow-up Python-newbie question: how do I make calls to fast-gpio in Python?

Jeff

[Lazar Demin]

@Jeff-Verive You can use the subprocess module: https://docs.python.org/2/library/subprocess.html