求大神赐教如何改变下面程序pwm的输出频率（最好给出详细的思路步骤）

ID:235126 · 发表于 2017-10-14 17:34

#include "reg51.h"

#define CYCLE 0x1000L    //定义PWM周期(最大值为32767)
#define DUTY 10L       //定义占空比为10%

#define PWMC       (*(unsigned int  volatile xdata *)0xfff0)
#define PWMCH    (*(unsigned char volatile xdata *)0xfff0)
#define PWMCL    (*(unsigned char volatile xdata *)0xfff1)
#define PWMCKS    (*(unsigned char volatile xdata *)0xfff2)
#define PWM2T1    (*(unsigned int  volatile xdata *)0xff00)
#define PWM2T1H    (*(unsigned char volatile xdata *)0xff00)
#define PWM2T1L    (*(unsigned char volatile xdata *)0xff01)
#define PWM2T2    (*(unsigned int  volatile xdata *)0xff02)
#define PWM2T2H    (*(unsigned char volatile xdata *)0xff02)
#define PWM2T2L    (*(unsigned char volatile xdata *)0xff03)
#define PWM2CR    (*(unsigned char volatile xdata *)0xff04)
#define PWM3T1    (*(unsigned int  volatile xdata *)0xff10)
#define PWM3T1H    (*(unsigned char volatile xdata *)0xff10)
#define PWM3T1L    (*(unsigned char volatile xdata *)0xff11)
#define PWM3T2    (*(unsigned int  volatile xdata *)0xff12)
#define PWM3T2H    (*(unsigned char volatile xdata *)0xff12)
#define PWM3T2L    (*(unsigned char volatile xdata *)0xff13)
#define PWM3CR    (*(unsigned char volatile xdata *)0xff14)
#define PWM4T1    (*(unsigned int  volatile xdata *)0xff20)
#define PWM4T1H    (*(unsigned char volatile xdata *)0xff20)
#define PWM4T1L    (*(unsigned char volatile xdata *)0xff21)
#define PWM4T2    (*(unsigned int  volatile xdata *)0xff22)
#define PWM4T2H    (*(unsigned char volatile xdata *)0xff22)
#define PWM4T2L    (*(unsigned char volatile xdata *)0xff23)
#define PWM4CR    (*(unsigned char volatile xdata *)0xff24)
#define PWM5T1    (*(unsigned int  volatile xdata *)0xff30)
#define PWM5T1H    (*(unsigned char volatile xdata *)0xff30)
#define PWM5T1L    (*(unsigned char volatile xdata *)0xff31)
#define PWM5T2    (*(unsigned int  volatile xdata *)0xff32)
#define PWM5T2H    (*(unsigned char volatile xdata *)0xff32)
#define PWM5T2L    (*(unsigned char volatile xdata *)0xff33)
#define PWM5CR    (*(unsigned char volatile xdata *)0xff34)
#define PWM6T1    (*(unsigned int  volatile xdata *)0xff40)
#define PWM6T1H    (*(unsigned char volatile xdata *)0xff40)
#define PWM6T1L    (*(unsigned char volatile xdata *)0xff41)
#define PWM6T2    (*(unsigned int  volatile xdata *)0xff42)
#define PWM6T2H    (*(unsigned char volatile xdata *)0xff42)
#define PWM6T2L    (*(unsigned char volatile xdata *)0xff43)
#define PWM6CR    (*(unsigned char volatile xdata *)0xff44)
#define PWM7T1    (*(unsigned int  volatile xdata *)0xff50)
#define PWM7T1H    (*(unsigned char volatile xdata *)0xff50)
#define PWM7T1L    (*(unsigned char volatile xdata *)0xff51)
#define PWM7T2    (*(unsigned int  volatile xdata *)0xff52)
#define PWM7T2H    (*(unsigned char volatile xdata *)0xff52)
#define PWM7T2L    (*(unsigned char volatile xdata *)0xff53)
#define PWM7CR    (*(unsigned char volatile xdata *)0xff54)

sfr PIN_SW2 = 0xba;

sfr P0M1 = 0x93;
sfr P0M0 = 0x94;
sfr P1M1 = 0x91;
sfr P1M0 = 0x92;
sfr P2M1 = 0x95;
sfr P2M0 = 0x96;
sfr P3M1 = 0xb1;
sfr P3M0 = 0xb2;
sfr P4M1 = 0xb3;
sfr P4M0 = 0xb4;
sfr P5M1 = 0xC9;
sfr P5M0 = 0xCA;
sfr P6M1 = 0xCB;
sfr P6M0 = 0xCC;
sfr P7M1 = 0xE1;
sfr P7M0 = 0xE2;

sfr PWMCFG  = 0xf1;
sfr PWMCR = 0xf5;
sfr PWMIF = 0xf6;
sfr PWMFDCR = 0xf7;

void main()
{
P0M0 = 0x00;
P0M1 = 0x00;
P1M0 = 0x00;
P1M1 = 0x00;
P2M0 = 0x00;
P2M1 = 0x00;
P3M0 = 0x00;
P3M1 = 0x00;
P4M0 = 0x00;
P4M1 = 0x00;
P5M0 = 0x00;
P5M1 = 0x00;
P6M0 = 0x00;
P6M1 = 0x00;
P7M0 = 0x00;
P7M1 = 0x00;

PIN_SW2 |= 0x80;             //使能访问XSFR
PWMCFG = 0x00;                //配置PWM的输出初始电平为低电平
PWMCKS = 0x00;                //选择PWM的时钟为Fosc/(0+1)
PWMC = CYCLE;                //设置PWM周期
PWM2T1 = 0x0000;             //设置PWM2第1次反转的PWM计数
PWM2T2 = CYCLE * DUTY / 100; //设置PWM2第2次反转的PWM计数
                                 //占空比为(PWM2T2-PWM2T1)/PWMC
PWM2CR = 0x00;                //选择PWM2输出到P3.7,不使能PWM2中断
PWMCR = 0x01;                //使能PWM信号输出
PWMCR |= 0x80;                //使能PWM模块
PIN_SW2 &= ~0x80;

while (1);
}

ID:111634 · 发表于 2017-10-15 21:14

本帖最后由 zl2168 于 2017-10-15 21:17 编辑

介绍你一个参考案例

直流电机正反转及PWM调速
先Proteus仿真一下，确认有效。

实例100 直流电机正反转及调速.rar (44.12 KB, 下载次数: 33)

以上摘自张志良编著《80C51单片机仿真设计实例教程——基于Keil C和Proteus》清华大学出版社ISBN 978-7-302-41682-1，内有常用的单片机应用100案例，用于仿真实验操作，电路与程序真实可靠可信可行。书中电路和程序设计有详细说明，程序语句条条有注解。仿真电路和Hex文件能在清华出版社网站免费下载，程序源代码只能到书上看了。到图书馆借，或到新华书店翻阅，或到网上书店打折购买。

ID:235126 · 发表于 2017-10-16 20:12

zl2168 发表于 2017-10-15 21:14
介绍你一个参考案例
直流电机正反转及PWM调速
先Proteus仿真一下，确认有效。

多谢答主解答

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求大神赐教如何改变下面程序pwm的输出频率（最好给出详细的思路步骤）

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