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; }