pwm.rar_PWM 50hz_pwm_pwm 50hz_测量占空比

#include "reg52.h" unsigned char code Duan[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f, 0x6f,0X76,0X3e,0x55,0x37,0x77,0x5e,0x72}; unsigned char Data_Buffer[4]={1,2,0,0}; unsigned char Pwm_out=50;//范围:10-90,步长为5 unsigned char Pwm_in=0; unsigned char th0_1,tl0_1,th0_0,tl0_0; sbit P10=P1^0; sbit P11=P1^1; sbit P12=P1^2; sbit P13=P1^3; sbit P23=P2^3; sbit P32=P3^2; sbit DOWN=P2^2; sbit UP=P2^1; bit flag=0; bit G_flag=0; //1:PWM正在输出高电平，0：PWM正在输出低电平 void Comute_pwmout() { float t; unsigned int x; t=20; t=t*Pwm_out/100;//计算高\低宽度时间ms为单位 t=t*921.6; t=65535-t; x=t; th0_1=x/256; tl0_1=x%256; t=20; t=t*(100-Pwm_out)/100;//计算高\低宽度时间ms为单位 t=t*921.6; t=65535-t; x=t; th0_0=x/256; tl0_0=x%256; Data_Buffer[0]=Pwm_out/10; Data_Buffer[1]=Pwm_out%10; } void main() { unsigned char Bit=0; unsigned int xx=100,yy=0; float t; bit x=1,y=1,z=1; Comute_pwmout(); TMOD=0x11; TH0=th0_1; TL0=tl0_1; TR0=1; ET0=1; EA=1; IT0=1; EX0=1; TH1=0; TL1=0; TR1=1; while(1) { if(UP==1)x=1;//pwm增加 else if(x==1) { x=0; Pwm_out+=5; if(Pwm_out>90)Pwm_out=90; Comute_pwmout(); } if(DOWN==1)y=1;//pwm减小 else if(y==1) { y=0; if(Pwm_out>10) Pwm_out-=5; Comute_pwmout(); } if(P32==0)z=1; else if(z==1)//P32上升沿 { z=0; TH1=0; //重新置0 TL1=0; TR1=1; } if(flag)//重新计算频率 { flag=0; xx=TH1*256+TL1; if(xx<yy-20||xx>yy+20)//PWM基本不变时，不用重新计算 { yy=xx; t=xx; t=t/921.6;//计算高电平的时间，MS为单位 t=t*(100/20);//周期为20MS,计算百分比 Pwm_in=t; Data_Buffer[2]=Pwm_in/10;//计算的频率在后两位数码管显示 Data_Buffer[3]=Pwm_in%10; } } Bit++;//数码管扫描 if(Bit>=4)Bit=0; P1|=0x0f; P0=Duan[Data_Buffer[Bit]]; switch(Bit) { case 0: P10=0;break; case 1: P11=0;break; case 2: P12=0;break; case 3: P13=0;break; } } } void timer0() interrupt 1 //方波发生定时器 { if(G_flag==0)//输出PWM的低电平 { TH0=th0_0; TL0=tl0_0;P23=0;G_flag=1; } else //输出PWM的高电平 { TH0=th0_1; TL0=tl0_1;P23=1;G_flag=0; } P32=P23;//实际当中应用线连接 } void int0() interrupt 0 //外部中断，P32作测频。 { flag=1; //需要更新PWM值 TR1=0;//下降沿,停止计数 }