[Grbl_Esp32 Issue#127] Proposal for software debouncing limit switches

Sorry for posting this as an issue, but I’m very new to git and I didn’t know where else to publish my idea:
I found a simple solution for debouncing and eliminate interferences on the limit switches by adding some subsequent extra reads of the inputs in the ISR before firing an alarm.
Since delays can’t be used in an ISR, I do an adjustable number of reads, in my case 3 worked fine.
I added following declarations in the top of “grbl_limits.cpp”:

“C
volatile byte readresult=0;
#define DEBOUNCEREADS 3
`

Then, at the beginning of void IRAMATTR isrlimit_switches(), I do subsequent readings of the limit inputs:

`C
readresult=0;
for (byte N=0; NLIMITPIN)==HIGH) || (digitalRead(YLIMITPIN)==HIGH) || (digitalRead(ZLIMITPIN)==HIGH)) {readresult++;}
}
`

`C
if (readcount==DEBOUNCEREADS){
if ( ( sys.state != STATEALARM) & (bitisfalse(sys.state, STATE_HOMING)) ) {
if (!(sysrtexec_alarm)) {
[...]
}
}
}
“

Before my modification, I had some very annoying alarm triggers by interferences from my HF spindle, despite of having applied all hardware means of debouncing (capacitors and strong pullups). The modification eliminiated all theses interferences!
**BUT BEWARE!! :
My modified code doesn’t take into account any inverting settings for the limit pins!**
As I’m not so deep in the grbl code, I just didn’t know how to manage this…
Perhaps someone could pick up the idea and correct the code?