Custom M code, with input check

Hello,
i want to write custom M code file (M100), which is waiting for digital input signal from mesa 7i77 card.

I think i see somewhere an example in past, but i cant find now.
Can someone please help how to write this program?

I write many M codes based on this manual: linuxcnc.org/docs/html/gcode/m-code.html...html#mcode:m100-m199
But just with digital outputs (halcmd setp ... TRUE/FALSE), not with cycle which continuously reading/waiting for input.
I don know how to read / get the status of digital input.

I want something like this:

Best regards,
Attila.

Depending what exactly you are trying to do this might actually be simpler with just a simple o-sub anc an M66.
linuxcnc.org/docs/html/gcode/m-code.html#mcode:m66

I am not an expert with bash, and am not currently at a Linux machine, but something a bit like this ought to work.
stackoverflow.com/questions/12321469/ret...command-with-timeout

Thanks for quick replay,
After a little modification, the code works.
Now a can use input pins, in M codes

Can you post your working Code? I'm trying something similar.

Thanks Patrick

Hello,

sorry for late post. Here is the working code:

#!/bin/bash
A=0
CNT=0

until [ "$A" = TRUE ]; do
A=$(halcmd getp hm2_5i25.0.7i77.0.0.input-27)
sleep 0.5
let CNT=CNT+1
if [ "$CNT" = 10 ]; then
halcmd sets spindleGearChangeTimeoutAlarm TRUE
sleep 0.1
halcmd sets spindleGearChangeTimeoutAlarm FALSE
exit 0
fi

done
exit 0

Thanks!