Michael,

What exactly do you mean by:
"On some parts the internal timer is relatively slow." ?
The internal oscillator on most parts can be set to a maximum frequency of 16MHz (+/- 3MHz). Only the 'F300, the 'F301 and the 'F120 series have a 24.5MHz +/- 2% oscillator. These can be successfully used for baudrate generation.

I have just finished a design that uses a 3.68MHz resonator. This also has no problem achieving 'standard' baudrates. It also consumes only about 1 mA and is still faster than most run-of-the-mill 8051s! I love these things...

I agree with your analysis on the intended use of the internal oscillator. Note however, that the introduction of the 'precision' oscillator was in large part due to customer requests. There aren't many companies around that actually listen to their clients the way that Cygnal does. Another good reason to like them :o)

Have a great weekend,
Rob.

BTW Does anybody think this thread has drifted somewhat from its original topic, or is it just me? ;o)