- /*
- 用STC单片机输出50Hz正弦波,采用软件模拟PWM实现。
- 修改晶振频率需要修改定时器中断时间,频率可能不太准确,适当调整晶振频率以及中断频率。
- P3.2和P3.3口为输出口,用电容滤波后即可
- */
- #include "reg51.h"
- sfr P3M0=0xB2;
- sfr AUXR=0x8E;
- unsigned char code sindata[200] = { //正弦波数据
- 0x80, 0x84, 0x88, 0x8C, 0x90, 0x94, 0x98, 0x9C, 0xA0, 0xA3, 0xA7, 0xAB, 0xAF, 0xB2, 0xB6, 0xBA,
- 0xBD, 0xC1, 0xC4, 0xC7, 0xCB, 0xCE, 0xD1, 0xD4, 0xD7, 0xDA, 0xDD, 0xDF, 0xE2, 0xE4, 0xE7, 0xE9,
- 0xEB, 0xED, 0xEF, 0xF1, 0xF3, 0xF5, 0xF6, 0xF7, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFD, 0xFE, 0xFE,
- 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFD, 0xFD, 0xFC, 0xFB, 0xFA, 0xF9, 0xF7, 0xF6, 0xF5,
- 0xF3, 0xF1, 0xEF, 0xED, 0xEB, 0xE9, 0xE7, 0xE4, 0xE2, 0xDF, 0xDD, 0xDA, 0xD7, 0xD4, 0xD1, 0xCE,
- 0xCB, 0xC7, 0xC4, 0xC1, 0xBD, 0xBA, 0xB6, 0xB2, 0xAF, 0xAB, 0xA7, 0xA3, 0xA0, 0x9C, 0x98, 0x94,
- 0x90, 0x8C, 0x88, 0x84, 0x80, 0x7C, 0x78, 0x74, 0x70, 0x6C, 0x68, 0x64, 0x60, 0x5D, 0x59, 0x55,
- 0x51, 0x4E, 0x4A, 0x46, 0x43, 0x3F, 0x3C, 0x39, 0x35, 0x32, 0x2F, 0x2C, 0x29, 0x26, 0x23, 0x21,
- 0x1E, 0x1C, 0x19, 0x17, 0x15, 0x13, 0x11, 0x0F, 0x0D, 0x0B, 0x0A, 0x09, 0x07, 0x06, 0x05, 0x04,
- 0x03, 0x03, 0x02, 0x02, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06,
- 0x07, 0x09, 0x0A, 0x0B, 0x0D, 0x0F, 0x11, 0x13, 0x15, 0x17, 0x19, 0x1C, 0x1E, 0x21, 0x23, 0x26,
- 0x29, 0x2C, 0x2F, 0x32, 0x35, 0x39, 0x3C, 0x3F, 0x43, 0x46, 0x4A, 0x4E, 0x51, 0x55, 0x59, 0x5D,
- 0x60, 0x64, 0x68, 0x6C, 0x70, 0x74, 0x78, 0x7C
- };
- void InitTimer0(void){ //初始化100us定时器
- TMOD = 0x01;
- TH0 = 0x0F6;
- TL0 = 0x0A0;
- EA = 1;
- ET0 = 1;
- TR0 = 1;
- }
- void set_pwm(unsigned char pwm){ //输出PWM
- unsigned char npwm=~pwm; //反向PWM值
- P3=0xFB; //P3.2输出低电平
- while(pwm--); //正向值替减
- P3=0xF7; //P3.3输出低电平
- while(npwm--); //反向值替减
- }
- unsigned char a=0; //占空比数据,定时器中断修改后在死循环中输出
- unsigned char pc=0; //程序计数器,用于指定数据位置
- void main(){ //入口函数
- AUXR = AUXR|0x80; //设置AUXR寄存器
- P3M0 = 0x0C; //设置P3M0寄存器
- InitTimer0(); //初始化100us定时器
- while(1){ //死循环
- set_pwm(a); //输出PWM数据
- }
- }
- void Timer0Interrupt(void) interrupt 1{ //100us定时器中断
- TH0 = 0x0F6;
- TL0 = 0x0A0;
- a=sindata[pc]; //修改PWM占空比数据,运行结束后会输出给IO口
- pc++; //程序计数器加1
- if(pc > 200){ //程序计数器大于200
- pc=0; //程序计算器清零,防止输出其他无用数据
- }
-
- }
复制代码
|