38 kHz timing

Hello,

Your module helped me tremendously. Thanks for sharing!

Just FYI, with Micropython release "rp2-pico-w-20221118-unstable-v1.19.1-705-gac5934c96"
I did not get 38 kHz frequency of the IR carrier. I had to change the pio_wave function slightly to get closer to 38kHz:
OF_TIM = const(15) # Duty(30%) off time [us]

Best regards,

Xyphro
