2812DSP实验指导书(2)

实验三、cpu定时器实验

该实验以中断的方式，标记定时器中断的次数，根据不同的次数，点亮不同的灯。原程序如下：

/*************************头文件*********************************/ #include \ // DSP281x Headerfile Include File #include \ // DSP281x Examples Include File

/*************************定义函数说明***************************/ // Prototype statements for functions found within this file. interrupt void cpu_timer0_isr(void); 声明中断服务程序。

void ConfigCpuTimer(struct CPUTIMER_VARS *Timer, float Freq, float Period); 该函数在DSp281x_cputimers.c中定义 CpuTimer0也在该文件中定义。

/*************************主程序*********************************/

CpuTimer0是CPUTIMER_VARS的一个对象，CPUTIMER_VARS是一个结构体，在DSp281x_cputimers.h中定义。 void main(void) {

InitSysCtrl(); DINT; 关中断

InitPieCtrl();

// Disable CPU interrupts and clear all CPU interrupt flags: IER = 0x0000; IFR = 0x0000;

// Initialize the PIE vector table with pointers to the shell Interrupt

InitPieVectTable();

EALLOW; // This is needed to write to EALLOW protected registers PieVectTable.TINT0 = &cpu_timer0_isr;

将外设中断向量表中的int0，设置为cpu定时器中断服务程序的地址。 EDIS; // This is needed to disable write to EALLOW protected registers

InitCpuTimers(); // For this example, only initialize the Cpu Timers

// Configure CPU-Timer 0 to interrupt every second: // 100MHz CPU Freq, 1 second Period (in uSeconds) ConfigCpuTimer(&CpuTimer0, 100, 1000000); StartCpuTimer0();

是一个宏定义，在DSp281x_cputimers.h中定义。 // Enable CPU INT1 which is connected to CPU-Timer 0:

IER |= M_INT1;

// Enable TINT0 in the PIE: Group 1 interrupt 7 PieCtrlRegs.PIEIER1.bit.INTx7 = 1;

// Enable global Interrupts and higher priority real-time debug events: EINT; // Enable Global interrupt INTM

ERTM; // Enable Global realtime interrupt DBGM

for(;;) {

if(CpuTimer0.InterruptCount<1) {

asm(\ asm(\

*(int *)0x2200=0x0081; }

else if(CpuTimer0.InterruptCount<2) {

asm(\ asm(\

*(int *)0x2200=0x0042; }

else if(CpuTimer0.InterruptCount<3) {

asm(\ asm(\

*(int *)0x2200=0x0024; }

else if(CpuTimer0.InterruptCount<4) {

asm(\ asm(\

*(int *)0x2200=0x0018; }

else if(CpuTimer0.InterruptCount<5) {

asm(\ asm(\

*(int *)0x2200=0x0024; }

else if(CpuTimer0.InterruptCount<6) {

asm(\

asm(\

*(int *)0x2200=0x0042; }

else if(CpuTimer0.InterruptCount<7) {

asm(\ asm(\

*(int *)0x2200=0x0081; } else {

CpuTimer0.InterruptCount = 0; } } }

interrupt void cpu_timer0_isr(void) {

CpuTimer0.InterruptCount++;

// Acknowledge this interrupt to receive more interrupts from group 1 PieCtrlRegs.PIEACK.all = PIEACK_GROUP1; }

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