Notes

// Program to make a quiz buzzer using seven segment

#include<reg51.h>
unsigned int digi_val[10]={0x40,0xF9,0x24,0x30,0x19,0x12,0x02,0xF8,0x00,0x10}; // Hex value corresponding to the digits 0 to 9
sbit output_on_pin = P3^0; // Enable pin to enable the seven segment.
sbit stop_pin = P3^1; // Stop pin to reset the buzzer.
sbit buzzer_pin=P0^0; // Buzzer pin to sound the buzzer.
int flag;

void delay() // Time delay function
{
int i,j;
for(i=0;i<200;i++)
for(j=0;j<1275;j++);
}

void display(unsigned int current_dig) // Function to display the resultant digit on the seven segment and sound the buzzer.
{
P2=digi_val[current_dig];
output_on_pin = 1;
buzzer_pin=0;
delay();
buzzer_pin=1;
while(stop_pin != 0);
}

void buzzer() //Function to monitor the input switches
{
flag = 0;
while(1)
{
while (P1 == 0xFF);

while (P1 == 0xFE) //Check if switch 1 is pressed
{
flag = 1;
display(1);
}

while (P1 == 0xFD) //Check if switch 2 is pressed
{
flag = 2;
display(2);
}

while (P1 == 0xFB ) //Check if switch 3 is pressed
{
flag = 3;
display(3);
}

while (P1 == 0xF7 ) //Check if switch 4 is pressed
{
flag = 4;
display(4);
}

while (P1 == 0xEF ) //Check if switch 5 is pressed
{
flag = 5;
display(5);
}

while (P1 == 0xDF) //Check if switch 6 is pressed
{
flag = 6;
display(6);
}

while (P1 == 0xBF ) //Check if switch 7 is pressed
{
flag = 7;
display(7);
}

while (P1 == 0x7F ) //Check if switch 8 is pressed
{
flag = 8;
display(8);
}

P1 = 0xFF;
stop_pin = 1;
output_on_pin = 0;
}
}

void main()
{
output_on_pin=0;
stop_pin = 1;
P1 = 0xFF;
buzzer();

}