> Greetings,
>         I'm in the middle of trying to make some code to do RS232 reception
> and have a question. My idea is to have an interrupt on the start
> bit, then load the timer with some value and wait for it to time out
> and generate another interrupt at which time I can check the data
> line again to get the bit in. Then reset the timer with another
> value.. etc... Is it possible to have one interrupt more or less
> inside another interrupt? If so is there anything special that needs
> to be done?
>         Thanks for your time!
> James
>

The normal way to do interrupt driven RS232 reception is to have a
periodical interrupt running at 2 or 3 times the baud rate. The
interrupt samples the RX line and as soon as the start bit is
detected the interrupt changes the period to 1.25 resp. 4/3 of the
baud period. The interrupt can now sample the first databit and
change the period to the baud rate, and sample the rest of the
databits. After the last databit is sampled, change back to 2 or 3
times the baud rate and wait for the next databit.

Regards,
Danjel McGougan.