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TI大神,我现在是用pwm1的的PWM1A和pwm2的PWM2A和PWM2B,pwm1计数方式是TB_COUNT_UP(单调递增模式),pwm2用的是TB_COUNT_UPDOWN(增减模式),因为pwm2我需要有死区互补的脉冲来驱动,pwm1和pwm2都是200Khz的平率,现在我怎么能让pwm1和pwm2同步起来,调试了一天了,一直不行,请大师指点一下,怎么怎么配置了呢?可以同步吗?
TI大神,您好,我是如下这样配置的:
void InitPwm(void)
{
EALLOW;
SysCtrlRegs.PCLKCR0.bit.TBCLKSYNC = 0; // Stop all the TB clocks
EDIS;
//========================
// EPWM Module 1 config
EPwm1Regs.TBPRD = 150;//600; // Period = 1200 TBCLK counts
EPwm1Regs.TBPHS.half.TBPHS = 0; // Set Phase register to zero
EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UPDOWN; // Symmetrical mode
EPwm1Regs.TBCTL.bit.PHSEN = TB_DISABLE; // Master module
EPwm1Regs.TBCTL.bit.PRDLD = TB_SHADOW;
EPwm1Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // Clock ratio to SYSCLKOUT
EPwm1Regs.TBCTL.bit.CLKDIV = TB_DIV1;
EPwm1Regs.TBCTL.bit.SYNCOSEL = TB_CTR_ZERO; // Sync down-stream module
EPwm1Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
//EPwm1Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO; // load on CTR=Zero
//EPwm1Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO; // load on CTR=Zero
EPwm1Regs.AQCTLA.bit.CAU = AQ_CLEAR;//AQ_SET; // set actions for EPWM1A
EPwm1Regs.AQCTLA.bit.CAD = AQ_SET;//AQ_CLEAR;
//EPwm1Regs.AQCTLB.bit.CBU = AQ_SET; // set actions for EPWM1B
//EPwm1Regs.AQCTLB.bit.CBD = AQ_CLEAR;
// EPWM Module 2 config
EPwm2Regs.TBPRD = 150;//600; // Period = 1200 TBCLK counts
EPwm2Regs.TBPHS.half.TBPHS = 0; // Set Phase register to zero
EPwm2Regs.TBCTL.bit.CTRMODE = TB_COUNT_UPDOWN; // Symmetrical mode
EPwm2Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // Clock ratio to SYSCLKOUT
EPwm2Regs.TBCTL.bit.CLKDIV = TB_DIV1; // Slow just to observe on the scope
//EPwm2Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Slave module
//EPwm2Regs.TBCTL.bit.PRDLD = TB_SHADOW;
EPwm2Regs.TBCTL.bit.SYNCOSEL = TB_SYNC_IN; // sync flow-through
EPwm2Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Slave module
EPwm2Regs.TBCTL.bit.PRDLD = TB_SHADOW;
EPwm2Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm2Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm2Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO; // load on CTR=Zero
EPwm2Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO; // load on CTR=Zero
EPwm2Regs.AQCTLA.bit.CAU = AQ_CLEAR;//AQ_SET; // set actions for EPWM2A
EPwm2Regs.AQCTLA.bit.CAD = AQ_SET;//AQ_CLEAR;
EPwm2Regs.AQCTLB.bit.CBU = AQ_SET; // set actions for EPWM2B
EPwm2Regs.AQCTLB.bit.CBD = AQ_CLEAR;
EPwm1Regs.TBCTR = 0x0000;
//Run Time (Note: Example execution of one run-time instance)
//===========================================================
EPwm1Regs.CMPA.half.CMPA = SOURCE_EDAGE_PWM_MIN;//400; // adjust duty for output EPWM1A
// EPwm1Regs.CMPB = 100;//200; // adjust duty for output EPWM1B
EPwm2Regs.CMPA.half.CMPA = SOURCE_EDAGE_PWM_MIN;//500; // adjust duty for output EPWM2A
EPwm2Regs.CMPB = SOURCE_EDAGE_PWM_MIN;//300; // adjust duty for output EPWM2B
// Active Low complementary PWMs - setup the deadband
EPwm2Regs.DBCTL.bit.OUT_MODE = DB_FULL_ENABLE;
EPwm2Regs.DBCTL.bit.POLSEL = DB_ACTV_HIC;
EPwm2Regs.DBCTL.bit.IN_MODE = DBA_ALL;
EPwm2Regs.DBRED = 11;//EPWM2_MIN_DB;
EPwm2Regs.DBFED = 11;//EPWM2_MIN_DB;
EALLOW;
SysCtrlRegs.PCLKCR0.bit.TBCLKSYNC = 1; // Start all the timers synced
EDIS;
}
现在运行出来的结果是没有pwm1模块的1A和pwm2的2A没有真正的同步起来,两个上升沿还有35ns的一个时间差,我想请教一个您,这个时间差是怎么来的,我怎么可以配置成没有误差的同步,我感觉我现在没有同步起来,感觉只是启动起来了,看了半天手册没有搞明白是怎么回事了?
您好,大i神,我死区配置去掉还是不同步,总有一个时间差大约40ns左右吧,这是我示波器测出来的,黄色pwm1模块的波形,蓝色和紫色是pwm2模块的波形,一个是上升沿比较,一个下降沿的比较,您看看,我是不是可以通过配置EPwm2Regs.TBPHS.half.TBPHS 的值来进行同步处理呢?这个寄存器是用作干嘛的了呢?是不是计数器到周期值后从这个寄存器来读取初始值了呢?
你好,这个问题我碰到过,研究了很长时间才解决的。主要是同步脉冲来时上一级TB已经计数而下一级寄存器更新需要时间,所以有2个脉冲的固定误差。如果你只有一块芯片多路PWM需要同步,其实完全可以不用同步脉冲,各PWM一起给时钟就能自动同步的。你可以加我QQ1209738940,再详细探讨
正如楼上所说,使能同步信号会有一个或是两个的PWM时钟周期的误差。如果您是定频控制,两个PWM之间也没有相位角,可以不需要这个功能,同时使能PWM模块的时钟就可以实现同步。
如果是变频控制或是两个PWM模块间需要插入固定的或是给定的相位角的时候,需要时钟同步这个功能。