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Interrupt lines restriction

Posted: Mon Aug 03, 2015 3:52 pm
by lcheminade
Due to the processor hardware architecture there is only one interrupt line available for each input bit value. This means that input with same pin bit (ie PA0, PB0, PC0) can't be used as the same time to trigger an interrupt. On a TD1208:

interrupt.PNG
interrupt.PNG (17.05 KiB) Viewed 6055 times


From a practical point of view this means you should not setup an interrupt at the same time for the following pins:

SCL, DB2 and USR2
SDA and DB3

Please note that on a TD1204/5, USR2 is used by the GPS. Therefore if you want to use both the GPS and interrupt on SCL or DB2 then you need to reactivate the interrupt after using the GPS. But keep in mind that while using the GPS the interrupt on SCL and DB2 will not work anymore (you can poll their status though).