请教关于dspic33ev64gs502的PWM问题

关于dspic33ev64gs502的PWM问题

/*
* File:   main.c
* Author: jack
*
* Created on 2018?8?1?, ??8:38
*/
// FSEC






#include "xc.h"
#include "p33EP64GS502.h"
_FOSCSEL(FNOSC_FRC)
_FOSC(FCKSM_CSECMD & OSCIOFNC_ON)
_FWDT(WDTEN_OFF)
_FICD(ICS_PGD2 & JTAGEN_OFF)
_FDEVOPT(PWMLOCK_OFF)


int main(void)
{
    // Configure Oscillator to operate the device at 68 MHz
   // Fosc = Fin*M/(N1*N2), Fcy = Fosc/2
   // Fosc = 7.37*(76)/(2*2)= ~140Mhz for Fosc, Fcy = 70 MHz


   // Configure PLL prescaler, PLL postscaler, PLL divisor
   PLLFBD             = 74;   // M = PLLFBD + 2
   CLKDIVbits.PLLPOST =  0;   // N1 = 2
   CLKDIVbits.PLLPRE  =  0;   // N2 = 2


   __builtin_write_OSCCONH(0x01);     // New Oscillator selection FRC w/ PLL
   __builtin_write_OSCCONL(0x01);     // Enable Switch


   while(OSCCONbits.COSC != 0b001);    // Wait for Osc. to switch to FRC w/ PLL
   while(OSCCONbits.LOCK != 1);        // Wait for PLL to Lock


   // Setup the ADC and PWM clock for 120MHz
   /* Setup for the Auxiliary clock to use the FRC as the REFCLK */
   // ((FRC * 16) / APSTSCLR ) = (7.37MHz * 16) / 1 = 117.9MHz


   ACLKCONbits.FRCSEL   = 1;          // FRC provides input for Auxiliary PLL (x16)
   ACLKCONbits.SELACLK  = 1;          // Aux Osc. provides clock source for PWM & ADC
   ACLKCONbits.APSTSCLR = 7;          // Divide Auxiliary clock by 1
   ACLKCONbits.ENAPLL   = 1;          // Enable Auxiliary PLL


   while(ACLKCONbits.APLLCK != 1);  // Wait for Auxiliary PLL to Lock
//   __delay_us(50);                  // Errata#1 (reference:DS80000656A)


   
   ANSELB = 0x0000;//????
   ANSELA = 0x0000;//????
   IOCON1 =0xC800;
IOCON2 = IOCON3 = 0xC800;
/* Set Independent Time Bases and Phase, Edge-Aligned Mode and Independent Duty Cycles */
PWMCON1 = PWMCON2 = PWMCON3 = 0x0000;
/* Configure Faults */
FCLCON2 = FCLCON1 = FCLCON3 = 0x0003;
/* 1:1 Prescaler */
PTCON2 = 0x0000;
/* Enable PWM Module */
PTCON = 0x8000;
PTPER = 6281;     //200K     // Buck/Boost converter switching Frequency (350 kHz)
PHASE1 = 0;
PHASE2 = 0;
PHASE3 = 0;//300;
/* Set Duty Cycles */
PDC1 = 240;
PDC2 = 240;
PDC3 = 240;
/* Set Dead Time Values */
DTR1 = 0;
DTR2 = 0;
DTR3 = 0;
ALTDTR1 = 0;
ALTDTR2 = 0;
ALTDTR3 = 0;
PTCONbits.PTEN = 1;     // Enable the PWM




    while(1)
    {
        
    }                       // End of While loop
}





















































































代码是使用例程改的，pwm波形很混乱，占空比和频率都不对。不知道哪里出了问题。求大神指导。。。。