TM4C129ENCPDT: ISR for interrupts from two gpio's

Raveena reddy

Part Number: TM4C129ENCPDT
Other Parts Discussed in Thread: EK-TM4C1294XL

Hi, I have two sensors which would output a digital pulse and that's fed to two gpios which are configured as input, I have initialised interrupt on both the gpios. my interrupt handler should trigger when any of the two sensors gives a pulse(high) and wait for the second sensor to give pulse (high), make a decision considering which gpio had high pulse first.

over 6 years ago

0 Bob Crosby over 6 years ago

TI__Guru 72500 points

OK, that is a reasonable project. I don't have an example that does exactly what you requested. The following example from the TivaWare library may be of some assistance.
C:\ti\TivaWare_C_Series-2.1.4.178\examples\boards\ek-tm4c1294xl\interrupts

0 Raveena reddy over 6 years ago in reply to Bob Crosby

Prodigy 100 points

Hi Bob, Thanks for replying, above example depicts prioritization between different GPIO ports, but i would need some sort of differentiation between pins of same port.

0 Bob Crosby over 6 years ago in reply to Raveena reddy

TI__Guru 72500 points

Using GPIO you would need to read the state of both pins in the interrupt routine to determine which one has gone high and which one has not. That means the time between the two rising edges must be long enough for the interrupt routine to read the pin state before the second pin goes high.

If the time between rising edges is not long enough for the interrupt routine to read the pins before the second one goes high, try using two general purpose time capture pins. Configure the two half times to start together. Then compare the capture values from the timers to determine which pin rising edge happened first.