Extend SoftwareTimer with option to make it non-repeating, add reset function & ISR-safe functions.

[MacGyverNL]

The SoftwareTimer provided by the library is missing a function for resetting it.

Also, I want to reset this timer from an ISR attached by attachInterrupt. Based on the documentation at https://www.freertos.org/FreeRTOS-timers-xTimerResetFromISR.html, I figured it was necessary to use the ISR-safe functions, so there's ISR-safe equivalents included. I'm not quite certain about their name, though; I used ISR because that was what was in my head at the time but it might be more appropriate to name them more in line with Arduino-style "attachInterrupt" thus becoming "resetFromInterrupt" etc.

Finally, the timer I want must be non-repeating, only getting started when an interrupt tells it to start. So I added a begin()-function that adds a boolean to its signature to specify whether the timer repeats if it ticks over or suspends.

See
https://github.com/MacGyverNL/bluepedal/blob/02213ee9dcc495ccdc47f572892f7388aac09a55/bluepedal/bluepedal.ino#L190
and
https://github.com/MacGyverNL/bluepedal/blob/02213ee9dcc495ccdc47f572892f7388aac09a55/bluepedal/bluepedal.ino#L281
for context of how I'm using them to implement a loopless HID.

[hathach]

Thank you for the PR, there is only a couple of slight change request. I am open for discussion.

[hathach]

Also if you are using attachInterrupt() but didn't need spot-on time, you can have the attachInterrupt() defer callback using ISR_DEFRRED option.

[MacGyverNL]

Also if you are using attachInterrupt() but didn't need spot-on time, you can have the attachInterrupt() defer callback using ISR_DEFRRED option.

I'm aware of the option, thanks. Most relevant for me is the behaviour of ISR_DEFERRED when multiple interrupts happen before the ISR is run, however -- does it run trhe ISR once for every single one or are all the interrupts rolled into a single run?

Regardless, assuming at some point someone will need spot-on timing for the ISR, and still need to also fire up a timer based on it, I think these additions should be made.

[hathach]

thanks for the PR and follow up :)