Can't enter VLP mode on Kinetis KL14

lfschrickte — Wed, 25 Sep 2013 18:48:31 GMT

Hi,

I can't entre VLP mode in my Kinetis KL14. The funcion VLPModeEnable hangs in the following while (marked in blue):

VLPModeEnable - where the app "stops"
LDD_TError Cpu_VLPModeEnable(void) { if (ClockConfigurationID != 1U) { return ERR_SPEED; /* Very low power mode not enabled in the active clock configuration. / } if (SMC_PMSTAT == 0x04U) { / If the system is already in VLP mode, return / return ERR_OK; } / SMC_PMCTRL: ??=0,RUNM=2,??=0,STOPA=0,STOPM=0 / SMC_PMCTRL = (SMC_PMCTRL_RUNM(0x02) \| SMC_PMCTRL_STOPM(0x00)); / Enable very low power mode / while(SMC_PMSTAT != 0x04U) { / Wait until in the Very Low Power run mode /* } return ERR_OK; }

VLPModeEnable - where the app "stops"

LDD_TError Cpu_VLPModeEnable(void)

{

if (ClockConfigurationID != 1U) {

return ERR_SPEED; /* Very low power mode not enabled in the active clock configuration. */

}

if (SMC_PMSTAT == 0x04U) { /* If the system is already in VLP mode, return */

return ERR_OK;

}

/* SMC_PMCTRL: ??=0,RUNM=2,??=0,STOPA=0,STOPM=0 */

SMC_PMCTRL = (SMC_PMCTRL_RUNM(0x02) | SMC_PMCTRL_STOPM(0x00)); /* Enable very low power mode */

while(SMC_PMSTAT != 0x04U) { /* Wait until in the Very Low Power run mode */

}

return ERR_OK;

}

Indeed I had this problem before and solved it by manually disabling a timed interrupt via a timer unit by calling TU1_Disable function before entering VLP.

I've been developing for a couple months and now the problem showed up again, but this time I can't figure the solution out.

Here is how I enter in VLP mode (I'm using User enter choice in PE options, so it is not entering VLP automatically when I set the corresponding clock configuration):

Entering VLP

		/* important: theoretically the SetClockConfiguration function below should disable it,
		* however in practice the TU1 must be disabled before it */
		TU1_Disable(dev_TU1);
		PWM1_Disable(dev_PWM1);

		/* set clock to configuration 1 (internal clock, BLPI, 0.03125 MHz) */
		Cpu_SetClockConfiguration(1);
		/* enter in low power mode */
		Cpu_VLPModeEnable();

And here is what I do when I want to return to Normal Mode:

Exiting VLP
/* disable Very Low Power Run Mode / Cpu_VLPModeDisable(); / set high frequency clock configuration - 16MHz / Cpu_SetClockConfiguration(0); / reenable TU1 PE device - see comment on TU1_Disable command below */ TU1_Enable(dev_TU1); PWM1_Enable(dev_PWM1);

Exiting VLP

/* disable Very Low Power Run Mode */

Cpu_VLPModeDisable();

/* set high frequency clock configuration - 16MHz */

Cpu_SetClockConfiguration(0);

/* reenable TU1 PE device - see comment on TU1_Disable command below */

TU1_Enable(dev_TU1);

PWM1_Enable(dev_PWM1);

I know the TU and PWM stuff should be done internally by the PE, but this was the only way it worked before.

The question is: what could be preventing me from entering VLP?

Thank you very much!

Luiz Fernando

Re: Can't enter VLP mode on Kinetis KL14

perlam_i_au — Wed, 25 Sep 2013 21:16:06 GMT

Hi Luiz:

I recommend you to check out this app note, specially 4.4 VLPR (Very Low Power Run).

Kinetis MicrocontrollersのトピックRe: Can't enter VLP mode on Kinetis KL14

Can't enter VLP mode on Kinetis KL14

Re: Can't enter VLP mode on Kinetis KL14