Interrupts again

14 Mar 2010

I have got my initial attempt at measuring short time durations between external start/stop signals working using a pair of GPIO ports on the mbed. I can measure accurately delays down to around 600 nsecs.  The limitation seems to be the time for the function below and its associated loop to execute

                 while(LPC_GPIOINT->IntStatus==0);

The delay seems to be around 560 ns after the input pulse is seen.

I would like to use two of the four external interrupt pins on the 1768. I assume from the schematic that pins 50 and 53 (EINT3 and EINT0) are used although their connections are not shown. Are pins 51 and 52 used? I think with a fine soldering iron I could attach leads to these pins.

Any help on using the external interrupt pins on the mbed would be appreciated.

John