Hi Adam,

please can your more explain what do you mean with: "somewhere it crashes" ?

If you lost some bytes on receive, I assume, your interrupts are too long in execution time (not in code size).

Try to do any interrupt as short as possible. Any action, which can be made later should be done in the main loop.

The interrupt priority must be distributed in respect of the needed response time:
A serial interrupt have many time until the next byte was completed, so low priority should be useful.
On timer interrupts it depends from the time interval, e.g. for intervals below 256 cycle the higher priority can be needed.
Also on external interrupts the minimal response time determine the priority.



Peter