EEPW论坛

#include  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; }