I needed a quick way to test hobby servos that didn't involve radios, etc. I had a PIC18F development board with an RS-232 port lying around, so I wrote a quick and dirty tester.

I'm providing the source (in PBP 3) and the .HEX file. It does require an 18F PIC with a hardware serial port and 16K or more of FLASH simply because it presents so much text to help the user. The serial port runs at 9600 N-8-1.

It produces 8 channels of PWM for the servos with a refresh rate of 50Hz (20 mSec). You can increase or decrease the pulse width with the "U" or "D" keys on the keyboard. D-T interrupts are used, and the ints are shut off when the registers are updated since the values are 16-bit.

All should be clear by looking at the source.

You can find the files at