> 2.  There is no internal hardware UART, and no baud-rate generator,
    >     it's all bit-banged in the 12F675.

    What's the difference between bit-banging and hardware uart anyway(except
    for the start-bit) ?? They are all derived from the same clock !

A bit-banged uart can use any number of CPU cycles for each bit.  A BRG is
usually restricted to a number of cycles that can be derived by dividing the
system clock by some integer or series of integers.  For instance, if my
clock is 100Hz, I can sample at 10, 11.1, 12.5, 14.28, or 16.67 Hz, but I'd
have signficant error trying to do 15Hz.  Bit-banged code could get closer.


    > 3.  *If* there was an F876 style BRG in the 12F675, it could be used
    >     at 9600 or 19,200 baud settings with negligible 0.16% errors
    >     (BRGH=1) due to the BRG.

In the general case, you need to consider that your bit-banged RC-clocked
uart that is 2% off is talking to a hardware uart that may also be 2% off,
even though you were counting on it being crystal-controlled and accurate,
just because someone on that side was lazy abotu picking a crystal freq.

BillW

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