Hi Vinod,

Given a 33 MHz clock, 1 instruction per clock, your minimum instruction execution time is 30 ns. But the conditional instructions like JB are 4 cycle instructions, so your minimum loop time is 120 ns.

You don't say how long these variable pulses have to be...so think about the impact of a timer ISR's latency to the already too-long minimum loop time.

Maybe you can have an external counter that generates the actual pulses (in CPLD perhaps) that the uC only has to control based on user input (from serial port perhaps).

Dennis