Chris Mabey

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6 years ago.  This question has been closed. Reason: Duplicate question

Using non-mbed pin for InterruptIn hangs custom board

I have built a custom board that uses many additional pins than those available on the mbed NXP LPC1768 prototyping board. This has been successful with one exception, the pin assigned to generate an interrupt on the rising edge of the input signal.

So, using mbed pin P18 (P0_26) works but using the pin P1_22 does not, the system hangs.

I have commenced investigations but would appreciate if anyone can give me a quick explanation to save time, for instance is it that only mbed pins can be used for interrupts?

Thanks, Chris.

OK, I've found the answer given by Simon Ford in response to a question in 2012! In case you're interested this is what Simon said.

"The LPC1768 chip has 3 i/o ports that drive the various GPIO pins, and can support interrupts on port 0 and port 2, but not port 1. The LEDs (and p19 and p20) are all on Port 1, so you can't trigger interrupts from those pins unfortunately (part of the reason we used those pins for the LEDs was they were some of the least flexible)."

Thanks Simon for that information!

posted by Chris Mabey 25 Oct 2018