AVR-Chat

On 5/30/07, stevech11 <stevech@san.rr.com> wrote:
> Grab AVRCalc off the projects section.
> If your oscillator was exactly 8MHz, the error at 38400 is small. I
> don't know what's involved in calibrating the on-board oscillator and
> how it's affected by temperature or Vcc changes.


Generally speaking, you need at least a resonator, or crystal, to do
accurate baud rates.
You have to factor in ALL the error sources.  First you have to allow
the other device at least half of the error budget, then figure your
divisor error, then min and max tolerance on the clock.
When you add it all up, the internal RC isn't good enough for serial.