Christopher E. Brown wrote: > I got out of rc racing several year ago, but even then the typical > units were switching at 2000hz+ and pwm the power to regulate motor speed. > > I am just learning about PICs, but is there really a problem with a mere > 2khz signal? > > How does the pwm out on the pics operate? Is it a set it and let it run > type, or do you set the width and trigger it each time? It depends on the PIC. Some of the high end ones have a couple of hardware PWM generators, which are great. The smaller ones don't though. There's no problem generating a 2Khz PWM, or reading a PCD(?) input from a radio control reciever. It's just that the accuracy of measuring the incoming pulse width is quite critical, and the pulse can last up to 2ms. At 2Khz PWM output, you will be disrupting between about 1 and 4 PWM cycles 50 times a second (every time the PWM generator code is interrupted to go read the input). If you wanted to use an expensive 16C62 or similar with hardware PWM and CCP modules, there would be no problem, the C compiler probably would produce suitable working code. If you want to use a 12CXX or 16X84 device though (which I believe they do), it will be a bit trickier. I'm not saying its impossible, just that I don't think you will come up with a satiscfactory solution with 10 lines of C code.