Some simple XC8 code for blinking and pulsing a warning LED for a PIC18F1320 fan speed monitor project. The dev system is Debian 32bit Linux with the Linux versions of MPLAB X IDE v3.26 and XC8 v1.37 free.

Code: pat.c contains main.
https://github.com/nsaspook/fanmon_xc8
https://github.com/nsaspook/fanmon_xc8/blob/master/fanmon.pdf

Leds are off when fans are at full speed. 120vac ebmpast 4606 ZH with speed sensor.
https://github.com/nsaspook/fanmon_xc8/blob/master/70105486.pdf

Programming ZIF socket testing. Slowing down the fan and letting it speed back up.

Processor ISR budget top trace: High in ISR, LOW running main program.

 

Prototype fan monitor board in an old school motor controller. Two leds soldered to the back on the Vector board tapping power from the controller electronics +5vdc supply.