EEPW论坛

#include <intrins.h>  
unsigned char tmp;  
sbit led0=P0^0;                           //指示灯0      
sbit led1=P0^1;                           //指示灯1      
sbit led2=P0^2;                           //指示灯2      
unsigned long PeriodCnt = 0; //PWM 周期计数值   
unsigned char HighRH = 0; //高电平重载值的高字节   
unsigned char HighRL = 0; //高电平重载值的低字节   
unsigned char LowRH = 0; //低电平重载值的高字节   
unsigned char LowRL = 0; //低电平重载值的低字节   
unsigned char T1RH = 0; //T1 重载值的高字节   
unsigned char T1RL = 0; //T1 重载值的低字节     
  
void ConfigPWM(unsigned int fr, unsigned char dc);   
void init();   //串口初始化  
void main()  
{                          
  
           init();  
          while(1)  
          {           
                  if(RI==1)                     //是否有数据到来  
                  {  
                   RI = 0;  
                  tmp = SBUF;                   //暂存接收到的数据  
                switch(tmp){  
case'1':    //前进  
EA=1;                                            
ConfigPWM(100, 10);   
while(1);  
break;  
default:     //停止  
   led0=1;   
                led1=1;                                 
                led2=1;  
             break;  
                                       }        
          }  
}  
void init()        //串口初始化  
{  
                   ES=0;                                                                       //关中断  
                     SCON = 0x50;                       位，1位停止位，无奇偶校验），波特率可变  
                     TMOD = 0x20;                          
          TH1=TL1=0xFD;                                
          PCON &= 0x7f;                     
          TR1 = 1;                                                                  
                     TI=0;                                                                        
                     RI=0;                     
                  
               ES=1;  
}  
  
/* 配置并启动 PWM，fr-频率，dc-占空比 */   
void ConfigPWM(unsigned int fr, unsigned char dc){   
    unsigned int high, low;   
    unsigned long tmp;        
    tmp = (11059200/12) / fr; //计算一个周期所需的计数值   
    high = (tmp*dc) / 100; //计算高电平所需的计数值   
    low = tmp - high; //计算低电平所需的计数值   
    high = 65536 - high + 12; //计算高电平的重载值并补偿中断延时   
    low = 65536 - low + 12;//计算低电平的重载值并补偿中断延时   
      
    HighRH = (unsigned char)(high>>8); //高电平重载值拆分为高低字节   
    HighRL = (unsigned char)high;   
    LowRH = (unsigned char)(low>>8); //低电平重载值拆分为高低字节   
    LowRL = (unsigned char)low;   
      
    TMOD &= 0xF0; //清零 T0 的控制位   
    TMOD |= 0x01; //配置 T0 为模式 1   
    TH0 = HighRH; //加载 T0 重载值   
    TL0 = HighRL;   
    ET0 = 1; //使能 T0 中断   
    TR0 = 1; //启动 T0   
    led0 = 0;   
led1=0;   
}   
  
/* T0 中断服务函数，产生 PWM 输出 */  
void InterruptTimer0() interrupt 1{   
  
led2=0;   
    }