//#####################################################################
//文件： DSP281x_SysCtrl.c
//说明： 初始化系统控制
//#####################################################################
#include "DSP281x_Device.h"
#include "DSP281x_Examples.h"
#pragma CODE_SECTION(InitFlash, "ramfuncs"); //将InitFlash函数存在ramfuncs中
//InitSysCtrl:初始化系统控制
void InitSysCtrl(void)
{
DisableDog(); //关看门狗
InitPll(0xA); //初始化PLL，用户要根据外部晶振的大小来改变实参
InitPeripheralClocks(); //初始化外设时钟
}
//喂狗子程序，如果用户使用看门狗，就可以调用该子程序
void KickDog(void)
{
EALLOW;
SysCtrlRegs.WDKEY = 0x0055;
SysCtrlRegs.WDKEY = 0x00AA;
EDIS;
}
//关闭看门狗子程序，在初始系统时，或者用户不想使用看门狗，可以调用该程序
void DisableDog(void)
{
EALLOW;
SysCtrlRegs.WDCR= 0x0068;
EDIS;
}
//初始化PLL
void InitPll(Uint16 val)
{
volatile Uint16 iVol;
if (SysCtrlRegs.PLLCR.bit.DIV != val)
{
EALLOW;
SysCtrlRegs.PLLCR.bit.DIV = val;
EDIS;
DisableDog(); //确保在进入下面循环前关闭看门狗
for(iVol= 0; iVol< ( (131072/2)/12 ); iVol++)
{
} //等待周期
}
}
//初始化外设时钟
void InitPeripheralClocks(void)
{
EALLOW;
SysCtrlRegs.HISPCP.all = 0x0001; //设定高速外设时钟预分频值
SysCtrlRegs.LOSPCP.all = 0x0002; //设定低速外设时钟预分频值
//对选定的外设进行外设时钟使能设置
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;
EDIS;
}
//=====================================================================
//本文件内还有一些与flash和CSM相关的子程序，不予列举，有兴趣的读者可以参考TI
//文献sprc097(可以到www.ti.com免费下载)。
//=====================================================================
//---------------------------------------------------------------------------
// Example: InitFlash:
//---------------------------------------------------------------------------
// This function initializes the Flash Control registers
// CAUTION
// This function MUST be executed out of RAM. Executing it
// out of OTP/Flash will yield unpredictable results
void InitFlash(void)
{
EALLOW;
//Enable Flash Pipeline mode to improve performance
//of code executed from Flash.
FlashRegs.FOPT.bit.ENPIPE = 1;
// CAUTION
//Minimum waitstates required for the flash operating
//at a given CPU rate must be characterized by TI.
//Refer to the datasheet for the latest information.
//Set the Random Waitstate for the Flash
FlashRegs.FBANKWAIT.bit.RANDWAIT = 5;
//Set the Paged Waitstate for the Flash
FlashRegs.FBANKWAIT.bit.PAGEWAIT = 5;
// CAUTION
//Minimum cycles required to move between power states
//at a given CPU rate must be characterized by TI.
//Refer to the datasheet for the latest information.
//For now use the default count
//Set number of cycles to transition from sleep to standby
FlashRegs.FSTDBYWAIT.bit.STDBYWAIT = 0x01FF;
//Set number of cycles to transition from standby to active
FlashRegs.FACTIVEWAIT.bit.ACTIVEWAIT = 0x01FF;
EDIS;
//Force a pipeline flush to ensure that the write to
//the last register configured occurs before returning.
asm(" RPT #7 || NOP");
}
//---------------------------------------------------------------------------
// Example: CsmUnlock:
//---------------------------------------------------------------------------
// This function unlocks the CSM. User must replace 0xFFFF's with current
// password for the DSP. Returns 1 if unlock is successful.
#define STATUS_FAIL 0
#define STATUS_SUCCESS 1
Uint16 CsmUnlock()
{
volatile Uint16 temp;
// Load the key registers with the current password. The 0xFFFF's are dummy
// passwords. User should replace them with the correct password for the DSP.
EALLOW;
CsmRegs.KEY0 = 0xFFFF;
CsmRegs.KEY1 = 0xFFFF;
CsmRegs.KEY2 = 0xFFFF;
CsmRegs.KEY3 = 0xFFFF;
CsmRegs.KEY4 = 0xFFFF;
CsmRegs.KEY5 = 0xFFFF;
CsmRegs.KEY6 = 0xFFFF;
CsmRegs.KEY7 = 0xFFFF;
EDIS;
// Perform a dummy read of the password locations
// if they match the key values, the CSM will unlock
temp = CsmPwl.PSWD0;
temp = CsmPwl.PSWD1;
temp = CsmPwl.PSWD2;
temp = CsmPwl.PSWD3;
temp = CsmPwl.PSWD4;
temp = CsmPwl.PSWD5;
temp = CsmPwl.PSWD6;
temp = CsmPwl.PSWD7;
// If the CSM unlocked, return succes, otherwise return
// failure.
if (CsmRegs.CSMSCR.bit.SECURE == 0) return STATUS_SUCCESS;
else return STATUS_FAIL;
}
//===========================================================================
// No more.
//===========================================================================