Measuring pulse shorter than 1 microsecond


Author Message
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 2027
Posted: 10:04am 22 Nov 2022      

Hi Pluto,

The PIO will put a new value in the FIFO every full cycle of the input signal.
When the input signal is relatively constant, all values will be roughly the same, and you can use all 5 values can be used (increase resolution by averaging).

For SSTV decoding (the PIO program was designed for that) I needed to make sure I had the most recent value, not fifo history. So I read 5 values (1 beyond FIFO size) to make sure the I have a recent value.

I did not know you could run the PIO at such high clock frequencies. That opens new opportinuties.... I thought it was limitted to 63MHz (126MHz/2) as all other peripherals (PWM).

Volhout