Two different period countdown timers that can show or hide seconds (based on 8051)

Functions implemented by the program:

1. After the experiment box is powered on, the two timers start timing, but no display is given.

2. If the "display seconds" command is sent to 8051, a specified countdown timer will display the seconds.

3. If the "hide seconds" command is sent to 8051, the specified countdown timer will be hidden for the specified number of seconds.

#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 the received command

int tcount = 0; //Record the number of 5ms intervals passed

int sec1 = 15, sec2 = 25; // countdown initial value

int sec1_ = 0, sec2_ = 0; //Real-time changes

int en1 = 0, en2 = 0; //Two timer seconds display flags, default is not displayed

void T0_INT() interrupt 1 //timer0 interrupt, triggered every 5ms

{

TR0 = 0; // turn off timer0

TH0 = 0xEC;

TL0 = 0x78; //65536 - 5000 = 60536

if(tcount % 4 == 0)

{

if(en1 == 1)

{

//Display the single digit (first countdown timer)

P2 = 0; // P2 = 0 -> (P24, P23, P22) = (0, 0, 0) -> the first number from the right lights up

P0 = DIG_CODE[sec1_ % 10];

}

tcount++;

}

else if(tcount % 4 == 1)

{

if(en1 == 1)

{

//Display the ten digits (first countdown timer)

P2 = 1 << 2; //P2 = 0000 0100 -> (P24, P23, P22) = (0, 0, 1) -> the second digit from the right lights up

P0 = DIG_CODE[sec1_ / 10];

}

tcount++;

}

else if(tcount % 4 == 2)

{

if(en2 == 1)

{

//Display the single digit (second countdown timer)

P2 = 100 << 2; //P2 = 0001 0000 -> (P24, P23, P22) = (1, 0, 0) -> the fifth number from the right lights up

P0 = DIG_CODE[sec2_ % 10];

}

tcount++;

}

else if(tcount % 4 == 3)

{

if(en2 == 1)

{

//Display the tens digit (second countdown timer)

P2 = 101 << 2; //P2 = 0001 0100 -> (P24, P23, P22) = (1, 0, 1) -> the sixth digit from the right lights up

P0 = DIG_CODE[sec2_ / 10];

}

tcount++;

}

if(tcount == 200)

{

tcount = 0;

if(-- sec1_ == -1)

{

sec1_ = sec1;

}

if(-- sec2_ == -1)

{

sec2_ = sec2;

}

}

TR0 = 1; //Restart timer0

}

int main()

{

int i = 0;

P2 = 111 << 2; //Select the first number from the left

P0 = 0; // Digital tube off

TMOD = 0x21;

SCON = 0x50; //Set serial communication format

TH0 = 0xEC;

TL0 = 0x78; //65536 - 5000 = 60536 = EC78H

TH1 = 0xE6;

TL1 = 0xE6;

IE = 0x82;

TR0 = 1; // turn on timer0

TR1 = 1; // turn on timer1

while(1)

{

if(RI == 1) //If data is received

{

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, "Show countdown 1st.E") == 0) //Show countdown 1st.E command

{

en1 = 1;

}

else if(strcmp(buf, "Hide countdown 1st.E") == 0) //Hide countdown 1st.E command

{

en1 = 0;

}

else if(strcmp(buf, "Show countdown 2nd.E") == 0) //Show countdown 2nd.E command

{

en2 = 1;

}

else if(strcmp(buf, "Hide countdown 2nd.E") == 0) //Hide countdown 2nd.E command

{

en2 = 0;

}

}

}

}

return 0;

}