On Tue, Jun 22, 2004 at 02:07:34PM -0700, Tom wrote:
> At 02:11 PM 6/22/04 -0400, you wrote:
> Many clever ways have been thought up to deal with this.  One method lets
> the PC start comms with some sync characters.  You measure these and bit
> bang a software uart padding as required to get acceptable bit times.


One that I had thought about briefly was to do the software sampling using the
standard RxD pin as an ordinary digital input. Then after getting the sample
rate, then set up the bitrate generator to closely match it as possible then
switch on the hardware USART.

> Lots easier to just get the right crystal...

True. However with the halfway decently specified tolerances on the
internal nanowatt (tm?) oscillators in the newer PICs it would be useful
to be able to run the part at 8 Mhz, use the hardware USART, and recover the
two I/O pins that the crystal would require.

Just a thought.

BAJ

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