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【求助】PIC18F46K22---PWM问题

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mcumail|  楼主 | 2017-2-22 21:32 | 显示全部楼层 |阅读模式
我写的PWM程序,一直没有仿真成功,哪位大神能点播一下,谢谢!
#include <xc.h>
#include"config.h"
#define _XTAL_FREQ 4000000
#define INT8U unsigned char
#define INT16U unsigned int
void Init_PWM();
void PWM_OUT(INT16U PwmOut);
//__delay_ms();
//__delay_us();
//*******主程序***********
void main()
{

    INT16U x0 = 512;
    Init_PWM();

    while(1)
    {
        PWM_OUT(x0);
    }
}

void Init_PWM()
{
    TRISCbits.RC2 = 1; //RC2/CCP1设置为禁止输出
    ANSELCbits.ANSC2 = 0;  //使能数字输出功能
//    CCPTMRS0bits.C1TSEL1 = 0;   
//    CCPTMRS0bits.C1TSEL0 = 0;
    CCPTMRS0bits.C1TSEL = 0x0;   //0000 0000 CPP1 PWM使用TMR2
    PR2 = 124;  //定时器初值:PR2=[500/(4*0.25*4)]-1=124=0x7C
   
//    CCP1CONbits.CCP1M3 = 1;
//    CCP1CONbits.CCP1M2 = 1;
//    CCP1CONbits.CCP1M1 = 0;
//    CCP1CONbits.CCP1M0 = 0;
    CCP1CONbits.CCP1M = 0xC; //0000 1100 设置为PWM模式
   
    CCP1CONbits.DC1B1 = 0;
    CCP1CONbits.DC1B0 = 0;
    CCPR1L = 0x80;           //0000 00[10 0000 00]00 初始占空比50%
   
    PIR1bits.TMR2IF = 0;  //清零中断标志位
//    T2CONbits.T2CKPS1 = 0;
//    T2CONbits.T2CKPS0 = 1;
    T2CONbits.T2CKPS = 0x1; //TMR2选择四分频
    T2CONbits.TMR2ON = 1; //开定时器开   
    TRISCbits.RC2 = 0; //RC2/CCP1设置为输出
//    PIE1bits.TMR2IE = 1;
//    INTCONbits.GIE = 1;
}
void PWM_OUT(INT16U PwmOut)
{
    CCP1CONbits.DC1B1 = (bit)(PwmOut >> 1);
    CCP1CONbits.DC1B0 = (bit)PwmOut;
    CCPR1L = (INT8U)(PwmOut >> 2);
}
//***********************************************************************************************************************************
//===================================配置位设置=========================================================
// CONFIG1H
#pragma config FOSC = XT        // Oscillator Selection bits (XT oscillator)
#pragma config PLLCFG = OFF     // 4X PLL Enable (Oscillator used directly)
#pragma config PRICLKEN = ON    // Primary clock enable bit (Primary clock is always enabled)
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config IESO = OFF       // Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)

// CONFIG2L
#pragma config PWRTEN = ON      // Power-up Timer Enable bit (Power up timer enabled)
#pragma config BOREN = NOSLP    // Brown-out Reset Enable bits (Brown-out Reset enabled in hardware only and disabled in Sleep mode (SBOREN is disabled))
#pragma config BORV = 285       // Brown Out Reset Voltage bits (VBOR set to 2.85 V nominal)

// CONFIG2H
#pragma config WDTEN = SWON     // Watchdog Timer Enable bits (WDT is controlled by SWDTEN bit of the WDTCON register)
#pragma config WDTPS = 1        // Watchdog Timer Postscale Select bits (1:1)

// CONFIG3H
#pragma config CCP2MX = PORTB3  // CCP2 MUX bit (CCP2 input/output is multiplexed with RB3)
#pragma config PBADEN = ON      // PORTB A/D Enable bit (PORTB<5:0> pins are configured as analog input channels on Reset)
#pragma config CCP3MX = PORTB5  // P3A/CCP3 Mux bit (P3A/CCP3 input/output is multiplexed with RB5)
#pragma config HFOFST = OFF     // HFINTOSC Fast Start-up (HFINTOSC output and ready status are delayed by the oscillator stable status)
#pragma config T3CMX = PORTC0   // Timer3 Clock input mux bit (T3CKI is on RC0)
#pragma config P2BMX = PORTD2   // ECCP2 B output mux bit (P2B is on RD2)
#pragma config MCLRE = EXTMCLR  // MCLR Pin Enable bit (MCLR pin enabled, RE3 input pin disabled)

// CONFIG4L
#pragma config STVREN = ON      // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
#pragma config LVP = ON         // Single-Supply ICSP Enable bit (Single-Supply ICSP enabled if MCLRE is also 1)
#pragma config XINST = OFF      // Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))

// CONFIG5L
#pragma config CP0 = OFF        // Code Protection Block 0 (Block 0 (000800-003FFFh) not code-protected)
#pragma config CP1 = OFF        // Code Protection Block 1 (Block 1 (004000-007FFFh) not code-protected)
#pragma config CP2 = OFF        // Code Protection Block 2 (Block 2 (008000-00BFFFh) not code-protected)
#pragma config CP3 = OFF        // Code Protection Block 3 (Block 3 (00C000-00FFFFh) not code-protected)

// CONFIG5H
#pragma config CPB = OFF        // Boot Block Code Protection bit (Boot block (000000-0007FFh) not code-protected)
#pragma config CPD = OFF        // Data EEPROM Code Protection bit (Data EEPROM not code-protected)

// CONFIG6L
#pragma config WRT0 = OFF       // Write Protection Block 0 (Block 0 (000800-003FFFh) not write-protected)
#pragma config WRT1 = OFF       // Write Protection Block 1 (Block 1 (004000-007FFFh) not write-protected)
#pragma config WRT2 = OFF       // Write Protection Block 2 (Block 2 (008000-00BFFFh) not write-protected)
#pragma config WRT3 = OFF       // Write Protection Block 3 (Block 3 (00C000-00FFFFh) not write-protected)

// CONFIG6H
#pragma config WRTC = OFF       // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected)
#pragma config WRTB = OFF       // Boot Block Write Protection bit (Boot Block (000000-0007FFh) not write-protected)
#pragma config WRTD = OFF       // Data EEPROM Write Protection bit (Data EEPROM not write-protected)

// CONFIG7L
#pragma config EBTR0 = OFF      // Table Read Protection Block 0 (Block 0 (000800-003FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR1 = OFF      // Table Read Protection Block 1 (Block 1 (004000-007FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR2 = OFF      // Table Read Protection Block 2 (Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks)
#pragma config EBTR3 = OFF      // Table Read Protection Block 3 (Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks)

// CONFIG7H
#pragma config EBTRB = OFF      // Boot Block Table Read Protection bit (Boot Block (000000-0007FFh) not protected from table reads executed in other blocks)
//================================================================================================================================================================

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Latin_newday| | 2017-2-23 11:40 | 显示全部楼层

#pragma config MCLRE = EXTMCLR  // MCLR Pin Enable bit (MCLR pin enabled, RE3 input pin disabled)
设置为MCLR功能,Pin脚却没接上拉5V,那不是一直复位?

INT16U x0 = 512;
PR2 = 124;  //定时器初值:PR2=[500/(4*0.25*4)]-1=124=0x7C
明明周期设置的是500,你却设置pwm输出512,比较条件永远不成立,就不可能出PWM波形了
此处应该设置为0-500之间的值。

    while(1)
    {
        PWM_OUT(x0);
    }

PWM设置好后,不需要一直设置,这样可能造成PWM波形抖动。


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参与人数 1威望 +3 收起 理由
mcumail + 3 很给力!
mcumail|  楼主 | 2017-2-23 14:33 | 显示全部楼层
本帖最后由 mcumail 于 2017-2-23 16:39 编辑
Latin_newday 发表于 2017-2-23 11:40
#pragma config MCLRE = EXTMCLR  // MCLR Pin Enable bit (MCLR pin enabled, RE3 input pin disabled)
...

感谢指点,是我对手册理解的不够,受教了!

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michaellengleng| | 2017-2-24 18:08 | 显示全部楼层
高手在民间啊

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