使用TLE984X系列MCU进行产品开发-电子发烧友网

使用TLE984X系列MCU进行产品开发，开发过程中参考官方例程配置SCU-CGU函数。 CGU全称为Clock Generation Unit(时钟产生单元)，使用官方工具箱配置时钟，模式为内部振荡器PLL，产生25MHz时钟信号。配置完成后，生成工程文件，可找遍了整个工程文件，也没有看到SCU初始化单元是怎么被执行的。下面是部分代码：

int main(void)
{
  /* Initialization of hardware modules based on Config Wizard configuration */
  TLE_Init();//函数初始化，包含SCU初始化函数

  /*****************************************************************************
  ** Place your application code here                                         **
  *****************************************************************************/
  
  
  /*****************************************************************************
  ** Main endless loop                                                        **
  *****************************************************************************/
  for (;;)
  {
    /* Main watchdog1 (WDT1) service */
//    (void)WDT1_Service();

    /***************************************************************************
    ** Place your application code here                                       **
    ***************************************************************************/
  }

void TLE_Init(void)
{
//#ifdef RTE_DEVICE_SDK_SCU
  SCU_Init();//SCU初始化函数
//#endif
//#ifdef RTE_DEVICE_SDK_PMU
  PMU_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_ADC1
//  ADC1_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_ADC2
//  ADC2_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_CCU6
//  CCU6_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_GPT12E
//  GPT12E_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_TRX
  TRX_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_HS
//  HS1_Init();
//#if (UC_FEAT_HS > 1u)
//  HS2_Init();
//#endif
//#endif
//#ifdef RTE_DEVICE_SDK_LS
//  LS1_Init();
//  LS2_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_MON
//  MONx_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_PORT
  PORT_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_SSC
//  SSC1_Init();
//  SSC2_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_TIMER2X
  TIMER2_Init();
  TIMER21_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_UART
//  UART1_Init();
//  UART2_Init();
//#endif
//#ifdef RTE_DEVICE_SDK_INT
//  INT_Init();
//#endif
}

void SCU_Init(void)
{
  /***************************************************************************
   ** System Clock Output Control                                           **
   ***************************************************************************/
  SCU->COCON.reg = (uint32) (SCU_COCON);

 /***************************************************************************
  ** Module Pin Select                                                     **
  **************************************************************************/
#ifdef SCU_MODPISEL
  SCU->MODPISEL.reg = (uint32) SCU_MODPISEL;
#endif
#ifdef SCU_MODPISEL1
  SCU->MODPISEL1.reg = (uint8) SCU_MODPISEL1;
#endif
#ifdef SCU_MODPISEL2
  SCU->MODPISEL2.reg = (uint8) SCU_MODPISEL2;
#endif
#ifdef SCU_MODPISEL3
  SCU->MODPISEL3.reg = (uint8) SCU_MODPISEL3;
#endif
  SCU->GPT12PISEL.reg = (uint8) SCU_GPT12PISEL;
}

第三段代码中，只是配置了fsys的分频及选择外部中断口，没有任何关于时钟源的选择及时钟配置相关的代码。百思不得其解（对启动文件未曾了解），使用keil工具进行Debug，将断点打在PC初始位置，PC：0x00000000，按下F10单步调试，指针会在当前汇编代码中逐步执行，且PC会跳转至SystemInit函数中执行。

PC初始化

SCU配置初始化函数

void SCU_ClkInit(void)
{
  sint32 int_was_mask;
  /* disable all interrupts                */
  int_was_mask = CMSIS_Irq_Dis();
  /***************************************************************************
   ** NVM Protection Control                                                **
   **************************************************************************/
#if (SCU_NVM_BOOT_PROT == 1u)
  (void)user_nvm_protect_set((uint32) SCU_NVM_PROT_PW, NVM_PASSWORD_SEGMENT_BOOT);
#endif
#if (SCU_NVM_CODE_PROT == 1u)
  (void)user_nvm_protect_set((uint32) SCU_NVM_PROT_PW, NVM_PASSWORD_SEGMENT_CODE);
#endif
#if (SCU_NVM_DATA_PROT == 1u)
  (void)user_nvm_protect_set((uint32) SCU_NVM_PROT_PW, NVM_PASSWORD_SEGMENT_DATA);
#endif
 /***************************************************************************
  ** PLL/SYSCLK Control                                                    **
  **************************************************************************/
  SCU->NMICON.bit.NMIPLL = 0u;

  /* enable XTAL1/2 pins */
  SCU_OpenPASSWD();
  SCU->MODPISEL1.reg = (uint32)(SCU_MODPISEL1 & SCU_MODPISEL1_XTAL12EN_Msk);
  SCU->PASSWD.reg = PASSWD_Close;

  /* select LP_CLK */
  SCU_OpenPASSWD();
  SCU->SYSCON0.bit.SYSCLKSEL = 2u;
  SCU_ClosePASSWD();

  /* Oscillator Select */
  SCU_OpenPASSWD();
  SCU->OSC_CON.reg = (uint32)SCU_OSC_CON;//
  SCU_ClosePASSWD();

  SCU_OpenPASSWD();
  SCU->PLL_CON.reg = (uint32) SCU_PLL_CON;
  SCU_ClosePASSWD();

  SCU_OpenPASSWD();
  SCU->CMCON1.reg = (uint32) SCU_CMCON1;
  SCU_ClosePASSWD();

  SCU->PLL_CON.bit.RESLD = 1u;
  /* set PLL_CON.bit.VCOBYP=0 */
  SCU->PLL_CON.reg=(SCU->PLL_CON.reg&~SCU_PLL_CON_VCOBYP_Msk)|SCU_PLL_CON_UNPROT_VCOBYP_Msk;
  /* set PLL_CON.bit.OSCDISC=0 */
  SCU->PLL_CON.reg=(SCU->PLL_CON.reg&~SCU_PLL_CON_OSCDISC_Msk)|SCU_PLL_CON_UNPROT_OSCDISC_Msk;

  while (u1_Field_Rd32(&SCU->PLL_CON.reg, (uint8)SCU_PLL_CON_LOCK_Pos, SCU_PLL_CON_LOCK_Msk) == (uint8)0)
  {
  }

  SCU_OpenPASSWD();
  /* 0u << 6u */
  SCU->SYSCON0.reg = 0u;//PLL OUT signal
  SCU_ClosePASSWD();

  SCU->NMISRCLR.bit.FNMIPLLC = 1u;
  
  /***************************************************************************
   ** Analog Clock Control                                                  **
   ***************************************************************************/

  /* set factor for MI_CLK and Filt_CLK*/
  SCU->APCLK.reg = (uint32) SCU_APCLK;

  /* apply setting by toggling APCLK_SET */
  SCU_OpenPASSWD();
  SCU->APCLK_CTRL.bit.APCLK_SET = 1u;
  SCU_ClosePASSWD();
  CMSIS_NOP();
  SCU_OpenPASSWD();
  SCU->APCLK_CTRL.bit.APCLK_SET = 0u;
  SCU_ClosePASSWD();

  /* enable interrupts                     */
  if (int_was_mask == 0)
  {
    CMSIS_Irq_En();
  }
}

Reset_Handler   PROC
                EXPORT  Reset_Handler               [WEAK]
                IMPORT  SystemInit
                IMPORT  __main
                LDR     R0, =SystemInit       
                BLX     R0
                LDR     R0, =__main
                BX      R0
                ENDP