dsp28035 epwm

user5860441

Intellectual 675 points

EPwm1Regs.TBCTL.bit.PRDLD = TB_IMMEDIATE; // Set immediate load
EPwm1Regs.TBPRD = period; // PWM frequency = 1 / perio

这两句是讲epwm文档上的103页的两句。

如果把这两句颠倒那么先前配置的TBPRD就会清0 ，为什么会这样？配置也要讲先后顺序？

6 年多前

0 mangui zhang 6 年多前

Guru 56631 points

周期寄存器配置肯定与上一句无关系可能是其他的配置导致清零了
如下面配置：
void Epwm1_Init(int16 PRD)
{
EPwm1Regs.TBPRD = PRD ; //设置周期
EPwm1Regs.CMPA.half.CMPA = 0; //设置占空比
EPwm1Regs.CMPB = 0;

// Setup TBCLK
EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP; //递增模式
//EPwm1Regs.TBCTL.bit.CTRMODE =TB_COUNT_UPDOWN; //增减模式
EPwm1Regs.TBCTL.bit.PHSEN = TB_DISABLE; // Disable phase loading
EPwm1Regs.TBCTL.bit.PRDLD = TB_SHADOW; // Disable phase loading
EPwm1Regs.TBCTL.bit.SYNCOSEL = TB_SYNC_DISABLE; //
EPwm1Regs.TBPHS.half.TBPHS = 0x0000; // Phase is 0
EPwm1Regs.TBCTR = 0x0000; // Clear counter
EPwm1Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // Clock ratio to SYSCLKOUT
EPwm1Regs.TBCTL.bit.CLKDIV = TB_DIV1; // TBCLK = SYSCLKOUT/(HSPCLKDIV*CLKDIV)

// Setup shadow register load on ZERO
EPwm1Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;
EPwm1Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO;

// 递增模式的动作
EPwm1Regs.AQCTLA.bit.ZRO = AQ_SET; // Set PWM1A on Zero
EPwm1Regs.AQCTLA.bit.CAU = AQ_CLEAR; // Clear PWM1A on event A, up count
EPwm1Regs.AQCTLB.bit.ZRO = AQ_SET; // Set PWM1B on Zero
EPwm1Regs.AQCTLB.bit.CBU = AQ_CLEAR; // Clear PWM1B on event B, up count
}