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How to use PWM to control the brightness of LED lights?

Question asked by codenoob on Mar 11, 2013
Latest reply on Aug 2, 2016 by Ken Carlo Ferry

Sorry for asking this basic question. I am very new to this area. My board is KL05Z.


From the reference manual, the duty cycle is determined by "CnV".  so I simply added the following lines to LED_Blink.c (before the while loop).


However, this did not work. When I run this piece of code in the board, it throws me to HardFault_Handler.


    TPM0_C0V = 1;
    TPM0_C1V = 1;
    TPM0_C2V = 1;
    TPM0_C3V = 1;
    TPM0_C4V = 1; 




What's the proper way of setting the duty cycles in PWM? I attached this piece of code in MKL05Z4.h, Hopefully it is easier for people with experience to look at.


Thanks a lot!

/** TPM - Peripheral register structure */
typedef struct TPM_MemMap {
  uint32_t SC;                                     /**< Status and Control, offset: 0x0 */
  uint32_t CNT;                                    /**< Counter, offset: 0x4 */
  uint32_t MOD;                                    /**< Modulo, offset: 0x8 */
  struct {                                         /* offset: 0xC, array step: 0x8 */
    uint32_t CnSC;                                   /**< Channel (n) Status and Control, array offset: 0xC, array step: 0x8 */
    uint32_t CnV;                                    /**< Channel (n) Value, array offset: 0x10, array step: 0x8 */
  } CONTROLS[6];
  uint8_t RESERVED_0[20];
  uint32_t STATUS;                                 /**< Capture and Compare Status, offset: 0x50 */
  uint8_t RESERVED_1[48];
  uint32_t CONF;                                   /**< Configuration, offset: 0x84 */
} volatile *TPM_MemMapPtr;



/* TPM - Register accessors */
#define TPM_SC_REG(base)                         ((base)->SC)
#define TPM_CNT_REG(base)                        ((base)->CNT)
#define TPM_MOD_REG(base)                        ((base)->MOD)
#define TPM_CnSC_REG(base,index)                 ((base)->CONTROLS[index].CnSC)
#define TPM_CnV_REG(base,index)                  ((base)->CONTROLS[index].CnV)
#define TPM_STATUS_REG(base)                     ((base)->STATUS)
#define TPM_CONF_REG(base)                       ((base)->CONF)

/* TPM - Register instance definitions */
/* TPM0 */
#define TPM0_SC                                  TPM_SC_REG(TPM0_BASE_PTR)
#define TPM0_CNT                                 TPM_CNT_REG(TPM0_BASE_PTR)
#define TPM0_MOD                                 TPM_MOD_REG(TPM0_BASE_PTR)
#define TPM0_C0SC                                TPM_CnSC_REG(TPM0_BASE_PTR,0)
#define TPM0_C0V                                 TPM_CnV_REG(TPM0_BASE_PTR,0)
#define TPM0_C1SC                                TPM_CnSC_REG(TPM0_BASE_PTR,1)
#define TPM0_C1V                                 TPM_CnV_REG(TPM0_BASE_PTR,1)
#define TPM0_C2SC                                TPM_CnSC_REG(TPM0_BASE_PTR,2)
#define TPM0_C2V                                 TPM_CnV_REG(TPM0_BASE_PTR,2)
#define TPM0_C3SC                                TPM_CnSC_REG(TPM0_BASE_PTR,3)
#define TPM0_C3V                                 TPM_CnV_REG(TPM0_BASE_PTR,3)
#define TPM0_C4SC                                TPM_CnSC_REG(TPM0_BASE_PTR,4)
#define TPM0_C4V                                 TPM_CnV_REG(TPM0_BASE_PTR,4)
#define TPM0_C5SC                                TPM_CnSC_REG(TPM0_BASE_PTR,5)
#define TPM0_C5V                                 TPM_CnV_REG(TPM0_BASE_PTR,5)
#define TPM0_STATUS                              TPM_STATUS_REG(TPM0_BASE_PTR)
#define TPM0_CONF                                TPM_CONF_REG(TPM0_BASE_PTR)
/* TPM1 */
#define TPM1_SC                                  TPM_SC_REG(TPM1_BASE_PTR)
#define TPM1_CNT                                 TPM_CNT_REG(TPM1_BASE_PTR)
#define TPM1_MOD                                 TPM_MOD_REG(TPM1_BASE_PTR)
#define TPM1_C0SC                                TPM_CnSC_REG(TPM1_BASE_PTR,0)
#define TPM1_C0V                                 TPM_CnV_REG(TPM1_BASE_PTR,0)
#define TPM1_C1SC                                TPM_CnSC_REG(TPM1_BASE_PTR,1)
#define TPM1_C1V                                 TPM_CnV_REG(TPM1_BASE_PTR,1)
#define TPM1_STATUS                              TPM_STATUS_REG(TPM1_BASE_PTR)
#define TPM1_CONF                                TPM_CONF_REG(TPM1_BASE_PTR)