This does not document M999 A1 to reset an attached paneldue (which is quite handy). Is that an omission in the documentation, or does it mean it’s a functionality that should not be relied upon?
The text says “When using PID to control the bed heater, RepRapFirmware uses a low PWM frequency (10Hz) so as to be compatible with all standard types of SSR”, but my Duet3 6HC configured by the web configtool, told to use PID on the bed H0 has a 250Hz PWM. I had to put a Q10 in the M950 H0 to get a low PWM frequency (which I want becasue it has a zero-crossing SSR on 50Hz mains).
I think the description of M280 is slightly wrong - on my RRF 3.1.1 on Duet3 hardware the S value is only treated as a pulse width if it is 544 or more (not above 200 as stated). Values 201-543 all generate a 2.395mS pulse width (same as a S199 according to my cheap oscilloscope).