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Blip in GPIO line when transitioning from VLLS3 to RUN

Question asked by Gaurav Banyal on Sep 4, 2017
Latest reply on Sep 6, 2017 by xiangjun.rong

Hello,

 

I am using an MKL03Z microcontroller and I am facing this issue which is impacting the system behavior very badly. Inside init_gpios() i initialize a GPIO pin to Output, HIGH. So when the system boots up, this line is set to high.

Next, the system enters VLLS3 state. Here, the status of that GPIO pin is maintained. When transitioning from VLLS3->RUN, I see a blip shown in the attached image which impacts my system very badly. How do I get rid of this (the yellow line in the scope is that GPIO and the green line is the wake-up source from VLLS3 to RUN)? I would avoid any hardware change at this point in the project. So adding a capacitor filtering won't be possible. This seems to be an MCU issue for now.

 

========

int main(void)
{
//Initialize event queue
EVENT_QUEUE_INITIALIZE( mainEventQueue, EVENT_QUEUE_SIZE );

/* Power related. */
SMC_SetPowerModeProtection(SMC, kSMC_AllowPowerModeAll);

if (kRCM_SourceWakeup & RCM_GetPreviousResetSources(RCM)){ /* Wakeup from VLLS. */
PMC_ClearPeriphIOIsolationFlag(PMC);
NVIC_ClearPendingIRQ(LLWU_IRQn);
}

/* Init board hardware. */
BOARD_InitBootPins();
BOARD_BootClockRUN();
init_gpios();

========

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