Using timer 0 to write a stopwatch (comments)

The stopwatch time is set by the timer, and the set time is displayed through the common cathode digital tube.

#include

#define uchar unsigned char

#define uint unsigned int

uchar code table [] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x40}; // Common cathode segment code table

uchar code table_SMG[] = {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07}; //bit selection

//------------------------Variable area------------------------

uchar count ; // count variable

uchar Time_T,Time_f,Time_s; //Contains time variables

//------------------------Function area------------------------

void Delay(uint t);//delay function

void Init_ET_0(); //Timer initialization function 50ms

void Display_SMG(uchar pos , uchar date); //Single digital tube display function (bit selection, segment selection)

void Display_Time(); //Time display function

void Delay(uint t) //delay function

{

while(t--);

}

void Init_ET_0() //Timer initialization function 50ms

{

TMOD = 0x01; //Timer 0 working mode 1

EA = 1; // Enable general interrupt

ET0 = 1; //Turn on the timer switch

TR0 = 1; //Start the timer

TH0 = (65536 - 50000)/256; //Assign initial value to the high eight bits

TL0 = (65536 - 50000)%256; //Assign initial value to the lower eight bits

}

void Servoic_ET_0() interrupt 1 //Timer service function

{

TH0 = (65536 - 50000)/256; //Reinstall the upper eight bits

TL0 = (65536 - 50000)%256; //Reinstall the lower eight bits

count++; //add once every 50ms

if(count == 20) // add 20 times to 1 second

{

Time_s++; //Increase once every 1 second

count = 0; //Release the variable value to make it timely for 50ms

if(Time_s == 60) //When it reaches 60S, add 1

{

Time_f++; // add 1 to the minute

Time_s = 0; //Set s to zero

if(Time_f == 60) //When it reaches 60 minutes, add 1

{

Time_T++; // add 1 to the time

Time_f = 0; //set time to zero

if(Time_T == 24) //When it reaches 24, set the time variable to zero

{

Time_T = 0; //Set the time variable to zero

}

}

}

}

}

void Display_SMG(uchar pos , uchar date) //Single digital tube display function (bit selection, segment selection)

{

P2 = table_SMG [pos]; //Position selection

P1 = date ;//segment selection

Delay(100); // Delay for a short time for dynamic display

}

void Display_Time() //Time display function

{

Display_SMG(7 , table [Time_s%10]); //Display the seconds

Display_SMG(6 , table [Time_s/10]); //Display the tens of seconds (recursive below)

Display_SMG(5 , table [10]); // separator

Display_SMG(4 , table [Time_f%10]);

Display_SMG(3 , table [Time_f/10]);

Display_SMG(2, table[10]);//separator

Display_SMG(1 , table [Time_T%10]);

Display_SMG(0 , table [Time_T/10]);

}

void main()

{

Init_ET_0(); //Timer 0 initialization

while(1)

{

Display_Time(); //Continuously refresh the display time

}

}

The simulation diagram is as follows