Jinx wrote: > I must say I was disappointed when first booting up a 12F675 with > internal RC. The "nominal" 4MHz turned out to be anything up to 4.3MHz. > I plan to use a one-wire data transfer from several 675s to another > micro, and because of the uncertainty an autobaud routine at the > receiver is necessary Depends on the protocol you use. Manchester encoding (with a decoder written intelligently), for instance, can easily tolerate that much variation in the clocks of the transmitter and receiver without any autobaud calculations... And so could a pulse-width scheme where, say, a 0 is a 50-microsecond (nominally) wide pulse, a 1 is a 100- microsecond-wide pulse, and there's a short gap between each bit. Or, easier, a scheme where a 0 is an x-microsecond gap followed by a 2x-microsecond pulse, and a 1 is a 2x-microsecond gap followed by an x-microsecond pulse (with a "start pulse" in front of your message, of course). -Andy === Andrew Warren - aiw@cypress.com === === Principal Design Engineer === Cypress Semiconductor Corporation _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist