Electronic clock based on 8051 (Version 1.1)

Functions implemented by the program:

1. After the experimental box is powered on, the current time is not displayed.

2. After sending "Start.E" to 8051, the electronic clock starts working and displays the current time (hours, minutes, seconds).

3. After sending "Stop.E" to 8051, the electronic clock stops working and hides the current time.

#include <STC89C5xRC.H>

#include

unsigned char code DIG_CODE[10] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f}; //The corresponding digital tube displays 0~9

char buf[30]; //Store received data

int tcount = 0; //Record the number of 2ms intervals passed

int hour = 23, minute = 59, second = 55;

void T0_INT() interrupt 1 //timer0 interrupt, triggered every 2ms

{

TR0 = 0; // turn off timer0

TH0 = 0xF8;

TL0 = 0x30;//65536 - 2000 = 63536 = F830H

if(tcount % 6 == 0)

{

// Seconds digit

P2 = 0; //The first number from the right is bright

P0 = DIG_CODE[second % 10];

tcount ++;

}

else if(tcount % 6 == 1)

{

//Tens of seconds

P2 = 1 << 2; //The second number from the right is lit

P0 = DIG_CODE[second / 10];

tcount ++;

}

else if(tcount % 6 == 2)

{

//Minutes digit

P2 = 2 << 2;

P0 = DIG_CODE[minute % 10];

tcount ++;

}

else if(tcount % 6 == 3)

{

//Tens of minutes

P2 = 3 << 2;

P0 = DIG_CODE[minute / 10];

tcount ++;

}

else if(tcount % 6 == 4)

{

//Hour digit

P2 = 4 << 2;

P0 = DIG_CODE[hour % 10];

tcount ++;

}

else if(tcount % 6 == 5)

{

//Tens of hours

P2 = 5 << 2;

P0 = DIG_CODE[hour / 10];

tcount ++;

}

if(tcount == 500) //2ms * 500 = 1000ms = 1s -> 1s time is up

{

tcount = 0;

second ++;

if(second == 60)

{

second = 0;

minute ++;

if(minute == 60)

{

minute = 0;

hour ++;

if(hour == 24)

{

hour = 0;

}

}

}

}

TR0 = 1; //Restart timer0

}

int main()

{

int i;

P2 = 111 << 2;

P0 = 0; // All digital tubes are off

TMOD = 0x21;

SCON = 0x50; //Set serial communication format

TH0 = 0xF8;

TL0 = 0x30;

TH1 = 0xE6;

TL1 = 0xE6;

IE = 0x82;

TR0 = 0; //Do not start timer0 yet

TR1 = 1; // Turn on timer1 to generate baud rate

while(1)

{

if(RI == 1) //Receive data

{

RI = 0;

buf[i++] = SBUF; //Receive data from the serial port

buf[i] = ''; //Manually add the end of string mark

if(i == 29) //Prevent array access out of bounds

{

i = 0;

}

if(buf[i - 1] == 'E') // reach the end

{

i = 0;

if(strcmp(buf, "Start.E") == 0) //Start.E command-> start the clock

{

TR0 = 1; //Start timer 0

}

else if(strcmp(buf, "Stop.E") == 0) //Stop.E command-> turn off the clock

{

TR0 = 0; // turn off timer 0

P2 = 111 << 2;

P0 = 0; // Clear Ping

}

}

}

}

return 0;

}