[Experimental] RMT TX support on ESP32: Looking for volunteers.

[crankyoldgit]

Hi all.
I've added some code via the branch rmt_on_esp32 which should produce better output on ESP32s. It uses the RMT module built in to the ESP32 to do the PWM mark generation for when transmitting signals. This should hopeful solve issues where the CPU was being interrupted by other activities. e.g. Bluetooth, WiFi, Interrupts etc.

I've tested it on a ESP32-WROOM-32 board using a newly aquired oscilloscope. The PWM signal and timings produced seem to be consistent and what I would expect

Can some folks who have an ESP32 please test it out with some real-world signal generation, please?!

There is still room for improvement.
e.g. perhaps sending the space() parts of the message using RMT as well.
I may also be able to tweak the PWM pulses even further to make them sub-uSec accurate too. But baby steps first

[crankyoldgit]

FYI. I have not gotten it to work yet on a ESP32-C3 SOC (e.g. Super mini board) ...