/* 单片机测频 程序 下到 20hz 上到 29k */
/*如果想要测更高频率可用模拟开关加分频器*/

/*说明： 头文件中调用的“lcd1602.h”只需要把我发的lcd1602的子程序做一个h文件即可*/

＃i nclude "AT89X52.h"
＃i nclude "stdio.h"
＃i nclude " absacc.h "
＃i nclude
＃i nclude
＃i nclude "lcd1602.h"

sbit F_in=P1^0;

bit int_flag;
unsigned int frequency;

void Display(void);
void Mcu_init(void);
void Measure_F(void);
void Measure_T(void);
void Frequency_Measure(void);

void main()
{ 
 Mcu_init(); 
 while(1)    
 {
  Frequency_Measure();
  Display();
 }
}

void time0(void)  interrupt 1 
{
 int_flag=1;
}

void Frequency_Measure(void)   
{
 if(frequency<2000)  
  Measure_T();
 else if(frequency>=2000)
  Measure_F();
}

void Measure_F(void)
{
 bit state_old=0,state_new=0;
 unsigned int f_count=0;  
 int_flag=0;
 TH0=-50000/256;
 TL0=-50000%256;
 TR0=1;
 while(1) 
 {
  state_new=F_in;
  if(state_old!=state_new) 
   f_count++;
  state_old=state_new;
  if(int_flag)
  {
   TR0=0; 
   frequency=f_count*10;
   return;
  }
 }
}

void Measure_T(void)
{
 bit state_old=0,state_new=0;
 unsigned char temp_flag=0;
 unsigned int t_count;
 
 TH0=0;
 TL0=0;
    while(1)
    {
     state_new=F_in; 
        if(state_old&&!state_new) 
        {
         temp_flag++;
         TR0=1;
        }
        if(temp_flag==2)
        {
         TR0=0;
         t_count=TH0*256+TL0; 
         frequency=1000000/t_count; 
         return;
        }
        state_old=state_new;
 }
}

void Display(void)
{
 unsigned char a,b,c,d,e;
 
 a=frequency/10000;
 b=frequency%10000/1000;
 c=frequency%1000/100;
 d=frequency%100/10;
 e=frequency%10;
 LCD_string(LINE1,0,"F-measure:"); 
 
 LCD_char(LINE1,0x0b,a 0x30);
 LCD_char(LINE1,0x0c,b 0x30);
 LCD_char(LINE1,0x0d,c 0x30);
 LCD_char(LINE1,0x0e,d 0x30);
 LCD_char(LINE1,0x0f,e 0x30);
 
 if(frequency<2000) 
  LCD_string(LINE2,0,"Now is measure T"); 
 else
  LCD_string(LINE2,0,"Now is measure F"); 
}

void Mcu_init(void)
{
 EA=1;
 ET0=1;
 TR0=1;
 TMOD=0x01;  
 TH0=-(50000/256); 
 TL0=-(50000%256);
 LCD_init();
 LCD_string(LINE1,0x00,"                        ");
 LCD_string(LINE1,0x00,"                        ");
}