epwm频率问题

只看该作者 · 2018-6-22 14:24

#define EPWM1_TIMER_TBPRD  2000  // Period register
#define EPWM1_MAX_CMPA    1950
#define EPWM1_MIN_CMPA    50
#define EPWM1_MAX_CMPB    1950
#define EPWM1_MIN_CMPB    50
这个1950和50是啥意思，下面的程序分频是为什么，频率是按2000那个算还是分频之后算啊？小白求教啊
EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP; // Count up
EPwm1Regs.TBPRD = EPWM1_TIMER_TBPRD;    // Set timer period
EPwm1Regs.TBCTL.bit.PHSEN = TB_DISABLE; // Disable phase loading
EPwm1Regs.TBPHS.half.TBPHS = 0x0000;    // Phase is 0
EPwm1Regs.TBCTR = 0x0000;                // Clear counter
EPwm1Regs.TBCTL.bit.HSPCLKDIV = TB_DIV2; // Clock ratio to SYSCLKOUT
EPwm1Regs.TBCTL.bit.CLKDIV = TB_DIV2;

// 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;

// Set Compare values
EPwm1Regs.CMPA.half.CMPA = EPWM1_MIN_CMPA; // Set compare A value
EPwm1Regs.CMPB = EPWM1_MIN_CMPB;             // Set Compare B value

// Set actions
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

// Interrupt where we will change the Compare Values
EPwm1Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO;    // Select INT on Zero event
EPwm1Regs.ETSEL.bit.INTEN = 1;             // Enable INT
EPwm1Regs.ETPS.bit.INTPRD = ET_3RD;          // Generate INT on 3rd event

// Information this example uses to keep track
// of the direction the CMPA/CMPB values are
// moving, the min and max allowed values and
// a pointer to the correct ePWM registers
epwm1_info.EPwm_CMPA_Direction = EPWM_CMP_UP; // Start by increasing CMPA & CMPB
epwm1_info.EPwm_CMPB_Direction = EPWM_CMP_UP;
epwm1_info.EPwmTimerIntCount = 0;          // Zero the interrupt counter
epwm1_info.EPwmRegHandle = &EPwm1Regs;       // Set the pointer to the ePWM module
epwm1_info.EPwmMaxCMPA = EPWM1_MAX_CMPA;    // Setup min/max CMPA/CMPB values
epwm1_info.EPwmMinCMPA = EPWM1_MIN_CMPA;
epwm1_info.EPwmMaxCMPB = EPWM1_MAX_CMPB;
epwm1_info.EPwmMinCMPB = EPWM1_MIN_CMPB;