Hello, I have decided to make a stand alone PIC that will operate as a Numerically Controlled Oscillator. This 'slave' PIC should be able to run the 16-Bit compare mode against Timer1. Inside the Compare interrupt, an I/O pin will toggle the opposite of last. High, then low, then high, etc... This new digital frequency should be glitch free. I would like to be able to update the 16-bit compare value, with a simple write from my master PIC. USART should have no problem with being constantly interrupted to toggle a pin. Is this true? I had problems with this type of constant interrupt when I was using a software SEROUT to write serially to my LCD. Many strange characters were displayed on the LCD. Ideally: Perfect communication between 2 PICs. With the slave PIC (receiver) operating with a 16-bit variable frequency. Any and all suggestions are appreciated!!!!! Thank you, 6500 7000 Dave Celsnak ___7500 / / 8000 (Shift!) /-/ / / RPM / / / /