Michael Rigby-Jones wrote:
> The bottom line is that ISR's should in most cases be designed to run
> as quickly as possible. In the case of a comms interrupt you would
> normally just take the data out of the UART register and add it to a
> circular buffer.  Your main program loop can than take data out of
> the buffer when it needs to.

Yes, and note how long you have to service the UART.  At 115.2Kbaud there
can be a character every 86.8uS, which is 434 instructions on a 20MHz PIC.
The interrupt routine to grab a byte from the UART and stuff it into a FIFO
should be only a small fraction of that.


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