ChibiOS Free Embedded RTOS

Above is my cfg structure for EXTI driver. Everything works ok apart from i get triggers when my application starts up.

In my application the inputs to the MCU can be switched on/off for low power reasons, thus my application starts up, enables the power to the inputs. The quiescent state of these inputs is high. But i find that as soon as i call extStart(&EXTD1, &extcfg); i get triggers on extcb1 and extcb2. I dont get any on extcb3 as this inputs quiescent state is low.

Is there away i can stop this happening ? Its like the driver assumes the default input state is low.

Are you sure you aren't simply getting noise or very brief pulses on the inputs?

Giovanni

Giovanni wrote:Are you sure you aren't simply getting noise or very brief pulses on the inputs?

Giovanni

Definatly not noise as the the input that is quiescent state low does not suffer from this issue

When the application starts, probably there is a transition from low to high on those inputs, is it possible you are getting that? also look for application notes about EXTI, the driver does nothing but call a function when an interrupt is triggered.

Giovanni

Giovanni wrote:When the application starts, probably there is a transition from low to high on those inputs, is it possible you are getting that? also look for application notes about EXTI, the driver does nothing but call a function when an interrupt is triggered.

Giovanni

There is a transition from low to high, this is where i turn on the input driver hardware. But i want to ignore that transistion but i'm not able to, and i'm not sure if the EXTI driver will allow me to ?

Basically so far i have tried this

Power System ON, Inputs to the MCU are low.
Enable Power to the Input Driver Hardware, at this point the inputs to the MCU are high.
Delay 1 second to let Input Driver Hardware settle.
Call extStart(&EXTD1, &extcfg);

After the call to extStart the callbacks are fired, but there as not been any transistions, only the ones previous at startup prior to extStart was called, but i delayed the start to try and remove these ?

Also worth nothing if i start up the offending channels with EXT_CH_MODE_FALLING_EDGE, i dont get the false trigger.

Could you try to reset the SR register at the end of the ext_lld_start() function? You can see the code in ext_lld_stop().

Giovanni

Giovanni wrote:Could you try to reset the SR register at the end of the ext_lld_start() function? You can see the code in ext_lld_stop().

Giovanni

Do you mean PR as in EXTI->PR ?

If so i tried this and it did not do anything, still get the trigger here is what i did

You have to put that line at the end of ext_lld_start() not after extStart() or the register is cleared after the interrupts have been enabled.

Giovanni

Giovanni wrote:You have to put that line at the end of ext_lld_start() not after extStart() or the register is cleared after the interrupts have been enabled.

Giovanni

does not make any differnece, still get the false trigger.

Also tried this, as wanted to make sure PR is been set



temp1 and temp2 are always 0x0

This should mean that the front is detected after the call to extStart(), there is no interrupt pending at that point.

Giovanni