This is simple program to control hardware PWM on Omega2. For some reason Omega2 has not any util to control hardware PWM. There is only fast-gpio tool, it uses software PWM which is awful for sound generation.
A few days after I got this all cleaned up, the Onion people did this the better way - they made a real kernel module that implements the kernel's SYSFS PWM interface: https://onion.io/2bt-hardware-pwm-omega2/
This makes this tool pretty much useless, but I'll leave it here in case someone wants it.
Channel #0 is pin #18, channel #1 is pin #19. Channels #2 and #3 are available on Omega2S only (UART2 pins).
Before usage you must set GPIO muxing using omega2-ctrl tool:
omega2-ctrl gpiomux set pwm0 pwm
omega2-ctrl gpiomux set pwm1 pwm
Then use this tool:
pwm <channel> <frequency> [duty]
Example to generate 3000Hz on channel #1 with 50% duty:
pwm 1 3000 50