T2做精确时钟

2019-04-15 18:02发布

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T2做精确时钟 52定时器/计数器T2一些寄存器的地址 //52，定时器T2 sfr     T2MOD = 0xC9;                            //T2MOD地址 sfr16  RCAP2 = 0xCA;                   //RCAP2地址   //sfr              T2CON = 0xC8;          //T2CON地址 //sfr              RCAP2L= 0xCA; //sfr              RCAP2H= 0xCB; //sfr              TH2   = 0xCD; //sfr              TL2   = 0xCC; //sfr              TR2   = 0xC8^2; //sfr              TF2   = 0xC8^7;   //T2初始化函数 void Timer2_Init(void) { TH2   = 0x4c;                     //65536-46080，设置初值46080，晶振22.1184MHz，定时25ms TL2   = 0x00;                      //65536-46080， RCAP2H = 0x4c;                  //TH2重装值 RCAP2L = 0x00;                   //TL2重装值   T2CON = 0x04;                    //T2工作模式，16位自动装载定时器方式 T2MOD = 0x10;                            //自动装载向上计数 IE    |= 0xa0; TR2   = 1; }   //T2中断处理函数 void Timer2(void) interrupt 5 { TF2 = 0;                                          // 溢出标志必须由软件清零 //EXF2 = 0;                                      // 捕获标志必须由软件清零        T2_Cycle++; if(T2_Cycle == 40)                        //循环40次，每次25ms，定时1s {            T2_Cycle = 0 ;                        T2_S++ ;              if(T2_S == 60)            {                     T2_S = 0;                       T2_M++;                       if(T2_M == 60)                     {                              T2_M = 0;                              T2_H++;                                                                     if(T2_H == 24)                              {                                        T2_H = 0;                               }                     }            } } } 以上是T2工作在自重载方式下的定时器，只要晶振很精确，T2做时钟就可以做到很精确，它的初值由硬件自重载，没有延迟，即使中断没有及时响应，计数器也正常计数。

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