topic Re: [Kw36] When exiting low power mode, RAM changes abnormally Low probability in Kinetis Microcontrollers

[Kw36] When exiting low power mode, RAM changes abnormally Low probability

UAES_ZhangBin — Tue, 03 Nov 2020 09:11:00 GMT

We use low power mode 1，and find

static void PWR_HandleDeepSleepMode_1(void)

{

........

if(gpfPWR_LowPowerEnterCb != NULL)
{
gpfPWR_LowPowerEnterCb();
}

BOARD_BLPEtoBLPI();
rfOscEn = RSIM_CONTROL_READ_FIELD(RSIM_CONTROL_RF_OSC_EN);
RSIM->CONTROL = RSIM_CONTROL_MODIFY_FIELD(RSIM_CONTROL_RF_OSC_EN, 0);
PWRLib_MCU_Enter_LLS3();
RSIM->CONTROL = RSIM_CONTROL_MODIFY_FIELD(RSIM_CONTROL_RF_OSC_EN, rfOscEn);

// RAM Variable keep , NO change

BOARD_BLPItoBLPE();

// RAM Variable happen change . It's unable to explain this phenomenon

if(gpfPWR_LowPowerExitCb != NULL)
{
gpfPWR_LowPowerExitCb();
}

........

}

Re: [Kw36] When exiting low power mode, RAM changes abnormally Low probability

nxf56274 — Wed, 04 Nov 2020 01:51:25 GMT

Hi,

How did you test the variable? Please describe it in detail. I made a simple test. Ram didn't change.

Have a great day,
TIC

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Re: [Kw36] When exiting low power mode, RAM changes abnormally Low probability

UAES_ZhangBin — Wed, 04 Nov 2020 02:59:36 GMT

This failure does not necessarily occur, the probability is extremely low.

uint8 A = 3; //global variable

void A_FaultTest（void）

{

if（A != 3）

{

while（1）{}；

}

A_FaultTest （）；

BOARD_BLPItoBLPE();

A_FaultTest （）；// when fault come, enter while (1). Varible A change cannot be detected by data write breakpoint.

Re: [Kw36] When exiting low power mode, RAM changes abnormally Low probability

nxf56274 — Wed, 04 Nov 2020 05:37:47 GMT

Hi,

I do the test in the application, not in the function PWR_HandleDeepSleepMode_1(void). This function will go to sleep. then recover from the sleep. May be in some time, we can't access the variable in this function. I add code in function BleApp_AdvertisingCallback.

if(A == 3)
{
AppPrintString("yes");
}

Here is the result.

At first , print yes. Then mcu go to sleep. I press button to wake. Print yes again. It means the variable doesn't change.

Have a great day,
TIC

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