使用单片机定时器中断控制LED闪烁

ID:1130312 · 发表于 2024-8-13 14:52

想实现的功能是按键第一次按下LED常亮（状态1），第二次按下LED发出SOS信号（状态2）（使用定时器中断控制LED先200ms闪烁三次,再500ms闪烁三次,再200ms闪烁三次，测试过SOS信号是正常的），第三次按下LED常灭（状态3），以此往复。现在出现了三个状态不稳定的情况（有时会直接跳过某个状态而进入下一个状态），请问是什么原因呢？以下是我的单片机代码
# include <STC8.h>
# include <intrins.h>
sbit KEY = P3 ^ 5;
sbit LED = P3 ^ 4;
unsigned int num = 0;
unsigned int LED_flag = 0;
unsigned int SOS_flag = 0;
void Init_IO()
{
P0M1 = 0x00;
P0M0 = 0x00;
P1M1 = 0x00;
P1M0 = 0x00;
P2M1 = 0x00;
P2M0 = 0x00;
P3M1 = 0x00;
P3M0 = 0x00;
P4M1 = 0x00;
P4M0 = 0x00;
P5M1 = 0x00;
P5M0 = 0x00;
P6M1 = 0x00;
P6M0 = 0x00;
P7M1 = 0x00;
P7M0 = 0x00;
}
void Timer0_Init(void)             //20ms@24.000MHz
{
      AUXR &= 0x7F;                      //12T
      TMOD &= 0xF0;
      TL0 = 0xC0;
      TH0 = 0x63;
      EA=1;
      TF0 = 0;
      TR0 = 0;
      ET0 = 1;

}
void Timer0_Isr(void) interrupt 1  //SOS信号
{
      TL0 = 0xC0;
      TH0 = 0x63;
      num++;
  SOS_flag = 1;
}
void display_sos(unsigned char state)
{
  static unsigned char st = 0;
  static unsigned char cnt1 = 0;
      if(state==0)
      {
               cnt1 = 0;
               st = 0;
               num =0;
               TL0 = 0xC0;
               TH0 = 0x63;
               TR0 = 1;//计时开始
      }

      if(SOS_flag==1)
      {
            SOS_flag = 0;
            if( st == 0)//三短
            {
                     if(num == 10)//200ms
                     {

                              num =0;
                              cnt1++;
                              if(cnt1==1)
                              {
                                       LED = 0;
                              }
                              else if(cnt1<=7)
                              {
                                       LED = ~LED;
                              }
                              else if(cnt1>7)
                              {
                                       st = 1;//三短结束，进入下一个状态————三长
                              }
                     }
            }
            if( st == 1)//三长
            {
                     if(num == 25 )//500ms
                     {
                              num =0;
                              cnt1++;
                              if(cnt1<=13)
                              {
                                       LED = ~LED;
                              }
                              else
                              {
                                       st = 2;//三长结束，进入下一个状态————三短
                              }
                     }
            }
            if( st == 2)//三短
            {
                     if(num == 10)//200ms
                     {
                              num =0;
                              cnt1++;
                              if(cnt1<=21)
                              {
                                       LED = ~LED;
                              }
                              else
                              {
                                       st = 3;//三短结束，进入间隔等待
                              }
                     }
            }
            if( st == 3)//每次sos信号间隔一秒
            {
                     if(num == 50)//1s
                     {
                              cnt1++;
                              num =0;
                              if(cnt1>21)
                              {
                                       LED =0;
                                       st = 0;
                                       cnt1=0;
                              }

                     }
            }
      }
}
void display()
{
      static unsigned char state = 0;
if (LED_flag == 0)
{
      LED = 0;
      state = 0;
}
else if (LED_flag == 1)//常亮状态
{
      LED = 1;
                        state = 0;
}
else if (LED_flag == 2)//SOS状态
{
      display_sos(state);
      state = 1;
}
else if (LED_flag == 3)//常灭状态
{
      LED = 0;
                        state = 0;
}


}

void KeyScan()
{
static unsigned char last_key_state = 1;
static unsigned char cnt = 0;

if (KEY != last_key_state)
{
      if (++cnt >= 3)
      {
         if (last_key_state == 0)
         {
            if (++LED_flag >= 3)
            {
                  LED_flag = 0;
            }
         }
         cnt = 0;
         last_key_state = KEY;
      }
}
else
{
      cnt = 0;
}
}
void main()
{
LED = 0;
Init_IO();
Timer0_Init();
while (1)
{
      KeyScan();
      display();

}
}