LPTMR does not work on FRDM-K20D50M

[yasuhikokoumoto]

Hi all.,

I am trying the wakeup from the low power mode by LPTMR on FRDM-K20D50M biard,.

However, it does not work.

The same code works well on the FRDM-KL25Z board.

I added  LLWUI bit to SMC_PMCTRL for Kinetis K.

Could anyone let me know the solution for FRDM-K20D50M?

The sample code is as follows.

The code was made by referring to the 'low_power_demo' of KL25 Sample Code.

--------[snip]-------

#include "common.h"

#define LPTMR_USE_IRCLK 0
#define LPTMR_USE_LPOCLK 1
#define LPTMR_USE_ERCLK32 2
#define LPTMR_USE_OSCERCLK 3

#define STOP_MODE  0x0
#define VLPS_MODE  0x2
#define LLS_MODE   0x3
#define VLLSx_MODE 0x4
#define VLLS0_MODE 0x0
#define VLLS1_MODE 0x1
#define VLLS2_MODE 0x2
#define VLLS3_MODE 0x3

#define  LLWU_irq_no            7  // Vector No 23
#define  LPTMR_irq_no           28  // Vector No 44

#define LOW_PWR_MODE  STOP_MODE
//#define LOW_PWR_MODE  VLPS_MODE
//#define LOW_PWR_MODE  LLS_MODE
//#define LOW_PWR_MODE  VLLSx_MODE

#define LOW_PWR_SMODE VLLS0_MODE
//#define LOW_PWR_SMODE VLLS1_MODE
//#define LOW_PWR_SMODE VLLS2_MODE
//#define LOW_PWR_SMODE VLLS3_MODE

void LPTMR_init()
{
    //SIM_SCGC5 |= SIM_SCGC5_LPTMR_MASK;
    SIM_SCGC5 |= 1; // SIM_SCGC5_LPTMR_MASK was not defined in FRDM-K20D50M

    LPTMR0_PSR = ( LPTMR_PSR_PRESCALE(0) // 0000 is div 2
                 | LPTMR_PSR_PBYP_MASK   // LPO feeds directly to LPT
                 | LPTMR_PSR_PCS(LPTMR_USE_LPOCLK)) ; // use the choice of clock
            
    LPTMR0_CMR = LPTMR_CMR_COMPARE(1000);  //Set compare value (100ms)

    LPTMR0_CSR =(  LPTMR_CSR_TCF_MASK   // Clear any pending interrupt
                 | LPTMR_CSR_TIE_MASK   // LPT interrupt enabled
                 | LPTMR_CSR_TPS(0)     //TMR pin select
                 |!LPTMR_CSR_TPP_MASK   //TMR Pin polarity
                 |!LPTMR_CSR_TFC_MASK   // Timer Free running counter is reset
                                        //  whenever TMR counter equals compare
                 |!LPTMR_CSR_TMS_MASK   //LPTMR0 as Timer
                );
    LPTMR0_CSR |= LPTMR_CSR_TEN_MASK|LPTMR_CSR_TFC_MASK;   //Turn on LPT and start counting
}

void STOP_Mode(void)
{
  /* Write to PMPROT to allow AVLP/LLS/AVLLS power modes this write-once
     bit allows the MCU to enter the AVLP/LLS/AVLLS low power mode*/
  SMC_PMPROT = SMC_PMPROT_AVLP_MASK
             | SMC_PMPROT_ALLS_MASK
             | SMC_PMPROT_AVLLS_MASK; 
  /* Set the STOPM field to 0b011 for LLS mode  */
  SMC_PMCTRL &= ~SMC_PMCTRL_STOPM_MASK;
  SMC_PMCTRL |=  SMC_PMCTRL_STOPM(LOW_PWR_MODE)|0x80;
#if (LOW_PWR_MODE == VLLSx_MODE)
  SMC_STOPCTRL &= ~SMC_STOPCTRL_VLLSM_MASK;
  SMC_STOPCTRL |= LOW_PWR_SMODE;
#endif
  /*wait for write to complete to SMC before stopping core */ 
  while((SMC_PMCTRL & SMC_PMCTRL_STOPM_MASK) != LOW_PWR_MODE);
  /* Now execute the stop instruction (deep sleep) to go into LLS */
  stop();
}

char *LOW_PWR_MODE_NAME[5]={
  "STOP",   "",   "VLPS",   "LLS",   "VLLSx"};

char *LOW_PWR_SMODE_NAME[4]={
  "VLLS0",   "VLLS1",   "VLLS2",   "VLLS3"};

int main (void)
{
      DisableInterrupts;
      enable_irq(LLWU_irq_no);
      enable_irq(LPTMR_irq_no);
      LLWU_ME = 1;  //Set up more modules to wakeup up
      LPTMR_init(); //LLS wake up after 100 ms
     
      printf("\nEntering %s mode\n\n\r",
            (LOW_PWR_MODE != VLLSx_MODE)?  LOW_PWR_MODE_NAME[LOW_PWR_MODE]
                                        :  LOW_PWR_SMODE_NAME[LOW_PWR_SMODE]);
      MCG_C6 &= ~MCG_C6_CME0_MASK;// set 0 before the MCG enters any Stop mode.
      STOP_Mode();
      MCG_C6 |= MCG_C6_CME0_MASK;
      LPTMR0_CSR &= ~LPTMR_CSR_TEN_MASK;
      printf("Back in RUN mode   \r");// dummy
      printf("Back in RUN mode \n\r");
      printf("FINISH\n");
}

--------[snip]-------

Best regards,

Yasuhiko Koumoto.

[Kan_Li]

Hi

There is a package for TWR-K20D50M already, and in which low power demo exists, so you need not port the one for KL25Z to K20D50M. You may download it directly from http://www.freescale.com/files/32bit/software/KINETIS_50MHZ_SC.zip?WT_TYPE=Lab%20and%20Test%20Softwa... .

Hope that helps,

Have a great day,
Kan

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[yasuhikokoumoto]

Hi Kan-san,

thank you for your comment.
However, I have already checked the TWR-K20D60M code. But it did not work. That is, the MCU did not wake up although it entered the low power mode. Also, the demo code does not use LPTMR. So it is not my intention.
I looked at the LPTMR behavior and I found LPTMR seemed not to work.
Can LPTMR use on the FRDM-K20D50M board?

Best regards,

Yasuhiko Koumoto.

[yasuhikokoumoto · Accepted solution]

Hi all.

I have found the reason why the sample code had not worked.

It is why the interrupt assignment of LLWU and TMPR for NVIC is different as follows.

#ifdef CPU_MKL25Z128LK4
#define  LLWU_irq_no            7

#define  LPTMR_irq_no           28
#endif

#ifdef MCU_MK20DZ50
#define  LLWU_irq_no        9 
#define  LPTMR_irq_no       39
#endif

By adding these definitions, I succeed to make the MCU woken up from the low power mode.

As for FRDM-K20D50M board, by entering the low power mode, serial clock is varied and

UART initialization is needed after exiting the low power mode.

Best regards,

Yasuhiko Koumoto.