K20DX256VHL7 内部时钟设置问题请教

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K20DX256VHL7用PE生成的，内部参考时钟FEI模式FLL到42M，时钟总是不对！串口打印出来的一直是乱码。求大神指导下内部参考时钟到底应该如何设置？
void __init_hardware(void)
{

  /*** !!! Here you can place your own code before PE initialization using property "User code before PE initialization" on the build options tab. !!! ***/

  /*** ### MK20DX256VLH7 "Cpu" init code ... ***/
  /*** PE initialization code after reset ***/
  SCB_VTOR = (uint32_t)(&__vect_table); /* Set the interrupt vector table position */
  /* Disable the WDOG module */
  /* WDOG_UNLOCK: WDOGUNLOCK=0xC520 */
  WDOG_UNLOCK = WDOG_UNLOCK_WDOGUNLOCK(0xC520); /* Key 1 */
  /* WDOG_UNLOCK: WDOGUNLOCK=0xD928 */
  WDOG_UNLOCK = WDOG_UNLOCK_WDOGUNLOCK(0xD928); /* Key 2 */
  /* WDOG_STCTRLH: ??=0,DISTESTWDOG=0,BYTESEL=0,TESTSEL=0,TESTWDOG=0,??=0,??=1,WAITEN=1,STOPEN=1,DBGEN=0,ALLOWUPDATE=1,WINEN=0,IRQRSTEN=0,CLKSRC=1,WDOGEN=0 */
  WDOG_STCTRLH = WDOG_STCTRLH_BYTESEL(0x00) |
                 WDOG_STCTRLH_WAITEN_MASK |
                 WDOG_STCTRLH_STOPEN_MASK |
                 WDOG_STCTRLH_ALLOWUPDATE_MASK |
                 WDOG_STCTRLH_CLKSRC_MASK |
                 0x0100U;

  /* System clock initialization */
  /* SIM_CLKDIV1: OUTDIV1=0,OUTDIV2=1,??=0,??=0,??=0,??=0,OUTDIV4=3,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
  SIM_CLKDIV1 = SIM_CLKDIV1_OUTDIV1(0x00) |
                SIM_CLKDIV1_OUTDIV2(0x01) |
                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,OUTDIV2=1,??=0,??=0,??=0,??=0,OUTDIV4=3,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
  SIM_CLKDIV1 = SIM_CLKDIV1_OUTDIV1(0x00) |
                SIM_CLKDIV1_OUTDIV2(0x01) |
                SIM_CLKDIV1_OUTDIV4(0x03); /* Update system prescalers */
  /* SIM_SOPT2: PLLFLLSEL=0 */
  SIM_SOPT2 &= (uint32_t)~(uint32_t)(SIM_SOPT2_PLLFLLSEL_MASK); /* Select FLL 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 */
  /* Switch to FEI Mode */
  /* MCG_C1: CLKS=0,FRDIV=0,IREFS=1,IRCLKEN=1,IREFSTEN=0 */
  MCG_C1 = MCG_C1_CLKS(0x00) |
           MCG_C1_FRDIV(0x00) |
           MCG_C1_IREFS_MASK |
           MCG_C1_IRCLKEN_MASK;
  /* MCG_C2: LOCRE0=0,??=0,RANGE0=0,HGO0=0,EREFS0=0,LP=0,IRCS=0 */
  MCG_C2 = MCG_C2_RANGE0(0x00);
  /* MCG_C4: DMX32=0,DRST_DRS=1 */
  MCG_C4 = (uint8_t)((MCG_C4 & (uint8_t)~(uint8_t)(
            MCG_C4_DMX32_MASK |
            MCG_C4_DRST_DRS(0x02)
           )) | (uint8_t)(
            MCG_C4_DRST_DRS(0x01)
           ));
  /* OSC_CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */
  OSC_CR = OSC_CR_ERCLKEN_MASK;
  /* MCG_C7: OSCSEL=0 */
  MCG_C7 &= (uint8_t)~(uint8_t)(MCG_C7_OSCSEL_MASK);
  /* MCG_C5: ??=0,PLLCLKEN0=0,PLLSTEN0=0,PRDIV0=0 */
  MCG_C5 = MCG_C5_PRDIV0(0x00);
  /* 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 internal reference clock. */
  }
  while((MCG_S & 0x0CU) != 0x00U) {    /* Wait until output of the FLL is selected */
  }
  /*** End of PE initialization code after reset ***/

  /*** !!! Here you can place your own code after PE initialization using property "User code after PE initialization" on the build options tab. !!! ***/

}

我知道答案 目前已有2人回答

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FSL_TICS_ZP

你可以先通过BUS clock引脚输出时钟频率，看看具体频率是多少？

aaa999kk

设置内部时钟, 要看频率, 最好先去看看示众配置方法