dsp28335呼吸灯代码

以下是DSP28335呼吸灯的代码：

#include "DSP2833x_Device.h"
#include "DSP2833x_Examples.h"

#define PWM_PERIOD 37500
//PWM 周期为 150MHz/(2*PWM_PERIOD) = 1KHz

Uint16 duty = 0;
Uint16 step = 1;

interrupt void epwm1_isr(void)
{
    EPwm1Regs.CMPA.half.CMPA = duty;
    duty += step;
    if(duty >= PWM_PERIOD || duty <= 0)
        step = -step;
    EPwm1Regs.ETCLR.bit.INT = 1;
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP3;
}

void Init_EPwm1(void)
{
    EPwm1Regs.TBPRD = PWM_PERIOD - 1;
    EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UPDOWN;
    EPwm1Regs.TBCTL.bit.PHSEN = TB_DISABLE;
    EPwm1Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1;
    EPwm1Regs.TBCTL.bit.CLKDIV = TB_DIV1;
    EPwm1Regs.TBCTL.bit.SYNCOSEL = TB_CTR_ZERO;
    EPwm1Regs.CMPA.half.CMPA = 0;
    EPwm1Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
    EPwm1Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;
    EPwm1Regs.AQCTLA.bit.CAU = AQ_SET;
    EPwm1Regs.AQCTLA.bit.CAD = AQ_CLEAR;
    EPwm1Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO;
    EPwm1Regs.ETSEL.bit.INTEN = 1;
    EPwm1Regs.ETPS.bit.INTPRD = ET_1ST;
}

void main(void)
{
    InitSysCtrl();
    InitPieCtrl();
    IER = M_INT3;
    Init_EPwm1();
    EINT;
    ERTM;
    while(1);
}

这段代码使用了DSP28335的EPWM模块来实现呼吸灯的效果。在中断服务函数中，改变PWM的占空比，从而控制LED的亮度。在主函数中，初始化系统、中断控制器、EPWM模块，并开启中断。