Hi,

tq for explaining.
Yes, actually i want to try adding 2 types of circuit protection system into my previous codes.

type 1 is basically come from outside signal called fault signal. when this fault signal is 5v, the PWM will operate in normal condition, however when fault signal is 0v PWM will stop operation (i thinking duty=0 instead of stopping the whole operation of PIC)

type 2 also from outside signal but from an op-amp. this op amp will compare the value of voltage. maximum output voltage from this opamp, i set to 3V. So when exceed 3V, the PIC will stop operation.

can you help assist what should i consider to design this kind of circuit protection in term of commands used, what should be define at PIC etc..?

thanks
photoelectric