Double External Interrupt

Benjamin Hudson

Other Parts Discussed in Thread: LAUNCHXL-F28069M

Hi there,

I'm trying to add some GPIO interrupts to my LAUNCHXL-F28069M project and I seem to be getting two interrupts on each trigger. I even tried adding a long delay in my interrupt to be sure that it wasn't a debouncing issue. I thought that the issue could be being caused by bank interrupts as well as direct interrupts but I don't think my board has bank interrupts. Does anyone know what might be causing this?

Thanks!

EDIT
I configured the pins to interrupt on the falling edge with 6 samples taken at the maximum sampling period for qualification

over 10 years ago

0 Gautam Iyer over 10 years ago

Guru 192875 points

Hi Ben,

Are you referring to External Interrupt here?

Regards,
Gautam

0 Benjamin Hudson over 10 years ago in reply to Gautam Iyer

Intellectual 555 points

Hi Gautam,

Yes, an external interrupt.

0 Gautam Iyer over 10 years ago in reply to Benjamin Hudson

Guru 192875 points

I hope your QUALPRDx is at maximum ie 0xFF.

0 Benjamin Hudson over 10 years ago in reply to Gautam Iyer

Intellectual 555 points

Yes it is

GpioCtrlRegs.GPAQSEL1.bit.GPIO0 = 2;
GpioCtrlRegs.GPACTRL.bit.QUALPRD0 = 0xFF;

0 Gautam Iyer over 10 years ago in reply to Benjamin Hudson

Guru 192875 points

Then you should not face this issue. So is this a switch or something else?

0 Bill Finger over 10 years ago

Genius 3735 points

Can you just go with it? That is, assume you will receive spurious interrupts, and instead use some other mechanism for re-arming the trigger. E.g.:

-- isr --

if (armed)

trigger = true;

else

// ignore

-- arming timer isr --

armed = true;

--- Main Body ---

armed = true;

for (;;) {

if (trigger) {

armed = false;

trigger = false;

set_arming_timer(ARM_TIMEOUT);

}

IDLE();

}

Regards,

Bill

0 Benjamin Hudson over 10 years ago in reply to Gautam Iyer

Intellectual 555 points

It's very strange. It's a button.

If at all possible, I'd prefer to figure out why it's happening!

0 Bill Finger over 10 years ago in reply to Benjamin Hudson

Genius 3735 points

The bouncing should be visible on a scope.

If you have access to the hardware, adding a filter capacitor may help considerably. Size it so the rise time is 100 msec or so. Assume a 20k pullup if you're using the DSP internal pullup.

0 Benjamin Hudson over 10 years ago in reply to Bill Finger

Intellectual 555 points

Bouncing wasn't causing the second interrupt.

Turns out I was enabling internal pullups when I didn't mean to be, so I disabled them and that fixed the problem!

0 Gautam Iyer over 10 years ago in reply to Benjamin Hudson

Guru 192875 points

Great!

Goodluck & Regards,
Gautam

C2000™︎ microcontrollers

C2000 microcontrollers forum

Double External Interrupt