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Why KL03 is not going into VLPW mode using Processor Expert?

Question asked by Andy Murray on Apr 11, 2018
Latest reply on Apr 13, 2018 by Mark Butcher

Hi, I am a newbie in KL03. The objective of my code is to run in VLPR and VLPW depending on an external signal. In both modes the LPTMR, ADC and the LPUART should be fully functional. I have checked the power demo of KL03 in which you are able to select among different power modes and the wake up source, everything works fine.


Using the KDS and Processor Expert I tried to configure the two modes of operation (VLPR and VLPW) and 1 type of callback, and even if I ask the PE to initialize the system in VLPW, it initializes in VLPR and is not able to get into the VLPW with the instruction

POWER_SYS_SetMode(kPowerManagerVlpw, PowerManagerPolicyAgreement);


While debugging, when I run this SetMode instruction, I see that in fsl_power_manager.c the variable mode is not set to kPowerManagerVlpw but to kPowerManagerVlpr. I force mode to be kPowerManagerVlpw in the debugger, and it works for a while. The KL03 executes the code:

        case kPowerManagerVlpw:

            halModeConfig.powerModeName = kPowerModeVlpw;



and in fsl_smc_hal.c it executes the code:

       case kPowerModeVlpw:

                 /* Clear the SLEEPDEEP bit to disable deep sleep mode - enter wait mode*/

                  SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;


Until it gets to wfi.


What should I do to avoid setting the mode to kPowerManagerVlpw using the debugger (which is not realistic)? Running in VLPR, I use the following instruction to get to VLPW:


// Errata 8068 fix

SIM->SCGC6 |=SIM_SCGC6_RTC_MASK;          // enable clock to RTC

RTC->TSR = 0x00; // dummy write to RTC TSR per errata 8068

SIM->SCGC6 &= ~SIM_SCGC6_RTC_MASK; // disable clock to RTC

ret_power=POWER_SYS_SetMode(kPowerManagerVlpw, kPowerManagerPolicyAgreement); 


After searching for this in the NXP Community, I decided to manage the transitions between power modes with the registers. The following is the code that I adapted from NXP community sources:


void goToVLPW(){

       int a;

       int clk;


       CLOCK_SYS_GetFreq(kCoreClock, &freq);


       // Errata 8068 fix:

       SIM->SCGC6 |=SIM_SCGC6_RTC_MASK;          // enable clock to RTC

       RTC->TSR = 0x00; // dummy write to RTC TSR per errata 8068

       SIM->SCGC6 &= ~SIM_SCGC6_RTC_MASK; // disable clock to RTC


       power_mode_status  = SMC_PMSTAT; //Pag. 206 RefMan

       if (power_mode_status == 4){

             //It is in VLPR

             SCB_SCR &=~ SCB_SCR_SLEEPDEEP_MASK; //SLEEPDEEP cleared; Pag. 213 RefMan

             SCB_SCR |= (SCB_SCR_SLEEPONEXIT_MASK); //Enter Sleep-On-Exit mode set

             dummyread = SCB_SCR;


             __asm("WFI");  //Enter VLPW


       power_mode_status  = SMC_PMSTAT; //Pag. 206 RefMan




How is it possible to work with the ADC, LPTMR and LPUART when operating in VLPW? Is there a way to check if I am really entering into that mode (without measuring the current consumption in my FRDM-KL03 board)? My interrupt will be based on a GPIO input.  


I really appreciate any help you can provide.