How to execute auto trim in kinetis KL26?

[PedroBecerra]

I've tried to trim my kinetis kl26. But I cannot see any change on MCG_C3 or MCG_C4 registers. So I think i'm wrong in some step.

First I configure kinetis to be clocked with an external 8MHz cristall.

And then I proceed with the auto trim internal 4MHz oscilator.

May be auto trim doesn't work if multilink is connectet?

All code is taken from processor expert unles the last 3 lines.

This is my trim code:

  SCB_VTOR = (uint32_t)(&__vect_table); /* Set the interrupt vector table position */

  /* Disable the WDOG module */

  SIM_COPC = SIM_COPC_COPT(0x00);                                  

  SIM_CLKDIV1 = (SIM_CLKDIV1_OUTDIV1(0x00) | SIM_CLKDIV1_OUTDIV4(0x03)); /* Set the system prescalers to safe value */

  /* SIM_SCGC5: PORTA=1 */

  SIM_SCGC5 |= SIM_SCGC5_PORTA_MASK;   /* Enable clock gate for ports to enable pin routing */

  if ((PMC_REGSC & PMC_REGSC_ACKISO_MASK) != 0x0U) {

    /* PMC_REGSC: ACKISO=1 */

    PMC_REGSC |= PMC_REGSC_ACKISO_MASK; /* Release IO pads after wakeup from VLLS mode. */

  }

  /* SIM_CLKDIV1: OUTDIV1=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,OUTDIV4=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */

  SIM_CLKDIV1 = (SIM_CLKDIV1_OUTDIV1(0x00) | SIM_CLKDIV1_OUTDIV4(0x00)); /* Update system prescalers */

  /* SIM_SOPT2: PLLFLLSEL=1 */

  SIM_SOPT2 |= SIM_SOPT2_PLLFLLSEL_MASK; /* Select PLL as a clock source for various peripherals */

  /* SIM_SOPT1: OSC32KSEL=3 */

  SIM_SOPT1 |= SIM_SOPT1_OSC32KSEL(0x03); /* LPO 1kHz oscillator drives 32 kHz clock for various peripherals */

  /* SIM_SOPT2: TPMSRC=0 */

  SIM_SOPT2 &= (uint32_t)~(uint32_t)(SIM_SOPT2_TPMSRC(0x03)); /* Set the TPM clock */

  /* PORTA_PCR18: ISF=0,MUX=0 */

  PORTA_PCR18 &= (uint32_t)~(uint32_t)((PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x07)));                                  

  /* PORTA_PCR19: ISF=0,MUX=0 */

  PORTA_PCR19 &= (uint32_t)~(uint32_t)((PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x07)));                                  

  /* MCG_SC: FCRDIV=0 */

  MCG_SC &= (uint8_t)~(uint8_t)(MCG_SC_FCRDIV(0x07));                                  

  /* Switch to FBE Mode */

  /* MCG_C2: LOCRE0=0,RANGE0=2,HGO0=0,EREFS0=1,LP=0,IRCS=1 */

  MCG_C2 = (uint8_t)((MCG_C2 & (uint8_t)~(uint8_t)(

            MCG_C2_LOCRE0_MASK |

            MCG_C2_RANGE0(0x01) |

            MCG_C2_HGO0_MASK |

            MCG_C2_LP_MASK

           )) | (uint8_t)(

            MCG_C2_RANGE0(0x02) |

            MCG_C2_EREFS0_MASK |

            MCG_C2_IRCS_MASK

           ));                                 

  /* OSC0_CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */

  OSC0_CR = OSC_CR_ERCLKEN_MASK;                                  

  /* MCG_C1: CLKS=2,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */

  MCG_C1 = (MCG_C1_CLKS(0x02) | MCG_C1_FRDIV(0x03) | MCG_C1_IRCLKEN_MASK);                                  

  /* MCG_C4: DMX32=0,DRST_DRS=0 */

  MCG_C4 &= (uint8_t)~(uint8_t)((MCG_C4_DMX32_MASK | MCG_C4_DRST_DRS(0x03)));                                  

  /* MCG_C5: ??=0,PLLCLKEN0=0,PLLSTEN0=0,PRDIV0=1 */

  MCG_C5 = MCG_C5_PRDIV0(0x01);                                  

  /* MCG_C6: LOLIE0=0,PLLS=0,CME0=0,VDIV0=0 */

  MCG_C6 = MCG_C6_VDIV0(0x00);                                  

  while((MCG_S & MCG_S_IREFST_MASK) != 0x00U) { /* Check that the source of the FLL reference clock is the external reference clock. */

  }

  while((MCG_S & 0x0CU) != 0x08U) {    /* Wait until external reference clock is selected as MCG output */

  }

  /* Switch to PBE Mode */

  /* MCG_C6: LOLIE0=0,PLLS=1,CME0=0,VDIV0=0 */

  MCG_C6 = (MCG_C6_PLLS_MASK | MCG_C6_VDIV0(0x00));                                  

  while((MCG_S & 0x0CU) != 0x08U) {    /* Wait until external reference clock is selected as MCG output */

  }

  while((MCG_S & MCG_S_LOCK0_MASK) == 0x00U) { /* Wait until locked */

  }

  MCG_SC = MCG_SC_ATMS_MASK;     //  internal 4MHz clock

  MCG_SC = MCG_SC_ATME_MASK | MCG_SC_ATMS_MASK;     // Activate Trim internal 4MHz clock

  while (MCG_SC & MCG_SC_ATME_MASK && !(MCG_SC & MCG_SC_ATMF_MASK)){}

[PedroBecerra · Accepted solution]

I've found my mistake.

I must to write to MCG_ATCVH and MCG_ATCVL before :

MCG_SC = MCG_SC_ATMS_MASK;     //  internal 4MHz clock

  MCG_SC = MCG_SC_ATME_MASK | MCG_SC_ATMS_MASK;     // Activate Trim internal 4MHz clock

  while (MCG_SC & MCG_SC_ATME_MASK && !(MCG_SC & MCG_SC_ATMF_MASK)){}

The code is this:

  register unsigned short ATCV;          // << Line added at the begining

.

.

.

  ATCV = 21 * 8 / 4 * 128;                  // Line added    8 is my reference clock,  4 is the internal Clock (both in MHz)  21 and 128 are given in the manual

  MCG_ATCVH = (unsigned char)((ATCV >> 8) & 0x00FF);           // Line added

  MCG_ATCVL = (unsigned char)(ATCV & 0x00FF);                      // Line added

  MCG_SC = MCG_SC_ATMS_MASK;     //  internal 4MHz clock

  MCG_SC = MCG_SC_ATME_MASK | MCG_SC_ATMS_MASK;     // Activate Trim internal 4MHz clock

  while (MCG_SC & MCG_SC_ATME_MASK && !(MCG_SC & MCG_SC_ATMF_MASK)){}

I hope it will be usefull for some one.