C51单片机 通过定时器模拟输出多路PWM

C51单片机 通过定时器模拟输出多路PWM

前言

1. 本博文基于STC89C52RC和keil5 C51开发；
2. 如有不做之处还请多多指教；

需要用到的东西

1. 利用定时器0完成（定时器1也一样）；
2. 利用P1.0~P1.3完成4路PWM的输出（不同的占空比）；

代码如下：

#include <STC89C5xRC.H>#define ENABLE 1
#define DISENABLE 0typedef unsigned int uint16;
typedef unsigned char uchar8;sbit  P1_0 = P1^0;
sbit  P1_1 = P1^1;
sbit  P1_2 = P1^2;
sbit  P1_3 = P1^3;/*
占空比的时间计算：
占空比 = High_Level_Time_P1_x/Cycle；
*/
uchar8 Cycle = 10;					//设置PWM周期：10*定时器溢出周期（100us）= 1000us；
uchar8 High_Level_Time_P1_0 = 0;    //这里四个全局变量控制每个周期内高电平时间；
uchar8 High_Level_Time_P1_1 = 0;
uchar8 High_Level_Time_P1_2 = 0;
uchar8 High_Level_Time_P1_3 = 0;   void Time0_Init(void);void main()
{Time0_Init();while(1);
}/*
定时器的配置：
1.假设单片机晶振频率为12MHz；则定时器累加周期为1us；
2.定时器初值为：9C（十进制的156，即定时器的溢出周期为100us）；
3.定时器0设置成8位自动重装载工作方式；
*/void Time0_Init(void)
{TMOD = 0x02;TH0 = 0x9C;TL0 = 0x9C;TR0 = ENABLE;	ET0 = ENABLE;EA = ENABLE;
}void Timer0_IT() interrupt 1
{ static uchar8 count_P1_0,count_P1_1,count_P1_2,count_P1_3; if(count_P1_0==High_Level_Time_P1_0){P1_0 = 0;}count_P1_0++;if(count_P1_0==Cycle){P1_0= 1;count_P1_0 = 0;}if(count_P1_1==High_Level_Time_P1_1){P1_1 = 1;}count_P1_1++;if(count_P1_1==Cycle){P1_1= 0;count_P1_1 = 1;}if(count_P1_2==High_Level_Time_P1_2){count_P1_2=0;}count_P1_2++;if(count_P1_2==Cycle){P1_2 = 0;count_P1_2=1;}if(count_P1_3==High_Level_Time_P1_3){count_P1_3 = 0;}count_P1_3++;if(count_P1_3==Cycle){P1_3 = 1;count_P1_3= 1;}
}