For a new design I'm currently using the 3.686MHz oscillator on the STK500. But on the board there's no space for a low-frequency crystal.
The only timing critical part of my program is RS232 communication for debugging. How stable is the internal 8MHz / divided down to 1MHz RC oscillator of the atmega48? Which RS232 divider settings do you recomend with this clock?
The design is going to go into production, so I have to be confident that the clock will work with chips from different batches and so on.