dsPIC33F之Center_Aligned_PWM

/**************************************************************************************
*  ?2008 Microchip Technology Inc.                                         
*                                                                           
*  FileName:              Center_Aligned_PWM.c                                    
*  Dependencies:          Header (.h) files if applicable, see below        
*  Processor:             dsPIC33FJ46GS610                                  
*  Compiler:              MPLAB?C30 v3.02 or higher                        
*  IDE:                   MPLAB?IDE v8.36.02 or later                         
*  Hardware Dependencies: explorer 16 board		             
*                                                                           
*  SOFTWARE LICENSE AGREEMENT:                                              
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* Description:                                                              
* This program sets up the PWM module for center aligned mode operation. The 
* PWM1 outputs are configured to produce a 400kHz PWM signal with independent 
* duty cycle. PWM1H produces 50% duty cycle and PWM1L produces 25% duty cycle.
* PWM2 outputs are configured to produce 400kHz PWM in complementary mode. The 
* duty cycle of PWM2 is 50%. 
*                                                                           
*                                                                           
*****************************************************************************/

#include "p33FJ64GS610.h"

/* Configuration Bit Settings */
_FOSCSEL(FNOSC_FRC)
_FOSC(FCKSM_CSECMD & OSCIOFNC_ON)
_FWDT(FWDTEN_OFF)
_FPOR(FPWRT_PWR128 )
_FICD(ICS_PGD1 & JTAGEN_OFF)

void init_PWM(void);

int main()
{
    /* Configure Oscillator to operate the device at 40Mhz
	   Fosc= Fin*M/(N1*N2), Fcy=Fosc/2
 	   Fosc= 7.37*(43)/(2*2)=80Mhz for Fosc, Fcy = 40Mhz */

	/* Configure PLL prescaler, PLL postscaler, PLL divisor */
	PLLFBD=41; 	/* M = PLLFBD + 2 */
	CLKDIVbits.PLLPOST=0;   /* N1 = 2 */
	CLKDIVbits.PLLPRE=0;    /* N2 = 2 */

    __builtin_write_OSCCONH(0x01);		/* New Oscillator FRC w/ PLL */
    __builtin_write_OSCCONL(0x01);  		/* Enable Switch */
      
	while(OSCCONbits.COSC != 0b001);	/* Wait for new Oscillator to become FRC w/ PLL */  
    while(OSCCONbits.LOCK != 1);		/* Wait for Pll to Lock */
	/* Now setup the ADC and PWM clock for 120MHz
	   ((FRC * 16) / APSTSCLR ) = (7.37 * 16) / 1 = ~ 120MHz*/

	ACLKCONbits.FRCSEL = 1;		/* FRC provides input for Auxiliary PLL (x16) */
	ACLKCONbits.SELACLK = 1;		/* Auxiliary Oscillator 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 */
    
	init_PWM();
    
    while(1);                   		/* Infinite Loop */
}

void init_PWM()
{
    
    /* ~~~~~~~~~~~~~~~~~~~~~~ PWM1 Configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */    
    IOCON1bits.PENH = 1;   			/* PWM1H is controlled by PWM module */
    IOCON1bits.PENL = 1;   			/* PWM1L is controlled by PWM module */
    IOCON1bits.PMOD = 3;   			/* Select Independent Output PWM mode */

    PWMCON1bits.CAM = 1;                    /* Select Center-aligned mode */
    PWMCON1bits.ITB = 1;                    /* Select Independent timebase mode (required for
                                               center-aligned mode) */
	
    PHASE1 = 1202;             		/* In Center-aligned mode the effective period of 
                                               the PWM signal is twice of the value in the 
                                               PHASEx register. So to obtain signal of 400kHz
                                               (or 2.5us period), the PHASE1 register should be
                                               configured for a period of 1.25us.
                                               PHASE1 = ((1.25us) / 1.04ns) = 1202. So effective
                                               period is 2.5us. */

    SPHASE1 = 1202;             		/* In Center-aligned mode the effective period of 
                                               the PWM signal is twice of the value in the 
                                               SPHASEx register. So to obtain signal of 400kHz
                                               (or 2.5us period), the SPHASE1 register should be
                                               configured for a period of 1.25us.
                                               SPHASE1 = ((1.25us) / 1.04ns) = 1202. So effective
                                               period is 2.5us. */
                                               
    PDC1 = 601;                 	/* In Center-aligned mode the effective duty cycle of 
                                               the PWM signal is twice of the value in the 
                                               PDCx register. To achieve 50% duty cycle configure
                                               PDCx register to 0.625us.
                                               PDC1 = ((0.625us) / 1.04ns) = 601. */
    
    SDC1 = 301;                 	/* In Center-aligned mode the effective duty cycle of 
                                               the PWM signal is twice of the value in the 
                                               SDCx register. To achieve 25% duty cycle configure
                                               PDCx register to 0.312us.
                                               PDC2 = ((0.312us) / 1.04ns) = 301. */
    

    /* ~~~~~~~~~~~~~~~~~~~~~~ PWM2 Configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */    
    IOCON2bits.PENH = 1;   			/* PWM1H is controlled by PWM module */
    IOCON2bits.PENL = 1;   			/* PWM1L is controlled by PWM module */
    IOCON2bits.PMOD = 0;   			/* Select Complementary Output PWM mode */

    PWMCON2bits.CAM = 1;                    /* Select Center-aligned mode */
    PWMCON2bits.ITB = 1;                    /* Select Independent timebase mode (required for
                                               center-aligned mode) */
	
    ALTDTR2 = 63;    			/* ALTDeadtime = (65ns / 1.04ns) where 65ns is desired deadtime
                                               When in center-aligned mode only use ALTDTRx */           
                         
    PHASE2 = 1202;             		/* In Center-aligned mode the effective period of 
                                               the PWM signal is twice of the value in the 
                                               PHASEx register. So to obtain signal of 400kHz
                                               (or 2.5us period), the PHASE1 register should be
                                               configured for a period of 1.25us.
                                               PHASE1 = ((1.25us) / 1.04ns) = 1202. So effective
                                               period is 2.5us. */

                                             
    PDC2 = 601;                 		/* In Center-aligned mode the effective duty cycle of 
                                               the PWM signal is twice of the value in the 
                                               PDCx register. To achieve 50% duty cycle configure
                                               PDCx register to 0.625us.
                                               PDC1 = ((0.625us) / 1.04ns) = 601. */
    

    PTCONbits.PTEN = 1;			  /* Enable the PWM Module */
}