//--------------------------------------------------------------------------

// Example: InitPeripheralClocks:

//---------------------------------------------------------------------------

// This function initializes the clocks to the peripheral modules.

// First the high and low clock prescalers are set

// Second the clocks are enabled to each peripheral.

// To reduce power, leave clocks to unused peripherals disabled

// Note: If a peripherals clock is not enabled then you cannot

// read or write to the registers for that peripheral

void InitPeripheralClocks(void)

{

 //等同汇编指令#define  EALLOW asm(" EALLOW")；原来TI的DSP为了提高安全性能，

//将很多关键寄存器作了保护处理。通过状态寄存器1（ST1）的位6设置与复位，来决定是否

//允许DSP指令对关键寄存器进行操作。这些关键寄存器包括：器件仿真寄存器、FLASH寄存

//器、CSM寄存器、PIE矢量表、系统控制寄存器、GPIOMux寄存器等等。

   EALLOW;

// HISPCP/LOSPCP prescale register settings, normally it will be set to default values

   SysCtrlRegs.HISPCP.all = 0x0001;  //High speed clock = SYSCLKOUT/2=75MHZ

   SysCtrlRegs.LOSPCP.all = 0x0002;

// Peripheral clock enables set for the selected peripherals.使能一些外设时钟：EVA,EVB,SCIA,

// SCIB ,MCBSP,SPI,ECAN,ADC的时钟被使能，通常为了降低功耗，没用到的外设，时钟关闭

   SysCtrlRegs.PCLKCR.bit.EVAENCLK=1;

   SysCtrlRegs.PCLKCR.bit.EVBENCLK=1;

   SysCtrlRegs.PCLKCR.bit.SCIAENCLK=1;

   SysCtrlRegs.PCLKCR.bit.SCIBENCLK=1;

   SysCtrlRegs.PCLKCR.bit.MCBSPENCLK=1;

   SysCtrlRegs.PCLKCR.bit.SPIENCLK=1;

   SysCtrlRegs.PCLKCR.bit.ECANENCLK=1;

   SysCtrlRegs.PCLKCR.bit.ADCENCLK=1;

//等同#define  EDIS   asm(" EDIS")，清除状态寄存器1的C6位，来防止杂散代码或指针破坏寄存器内容。

   EDIS;

}

转自《C2000手册》