Use of “Case” in 8051

To use this code, fix a Common Cathode type 7-segment LED display on a breadboard and connect its pins to PORT2 in following sequence P2^0 – a, P2^1 – b, P2^2 – c, P2^3 – d, P2^4 – e, P2^5 – f, P2^6 – g (P2^7 should be left open) and then connect the GROUND terminal of the display to -ve terminal of your 8051 microcontroller dev. board.

The Code

#include <reg51.h> // reg52 header file included
#include "delay.c" // customised delay file included
#define Display P2 // PORT2 is assigned to 'Display'

void main()	// main function started
{ // opening brace of main function

int i; // variable for counting 10 cases
Display=0xFF; // display shows '8' initially
delay(200);

while(1)
{
for(i=0;i<11;i++)
{
delay(50);

/* Display connection details with PORT2
PORT2 pins --> 7  6  5  4  3  2  1  0  	
displ pins --> X  g  f  e  d  c  b  a
*/	

switch(i)
{
case 0: 
Display=0x3F; // '0' is dispalyed
break;

case 1:
Display=0x06; // '1' is dispalyed
break;

case 2:
Display=0x5B; // '2' is dispalyed
break;

case 3:
Display=0x4F; // '3' is dispalyed
break;

case 4:
Display=0x66; // '4' is dispalyed
break;

case 5:
Display=0x6D; // '5' is dispalyed
break;

case 6:
Display=0x7D; // '6' is dispalyed
break;

case 7:
Display=0x07; // '7' is dispalyed
break;

case 8:
Display=0x7F; // '8' is dispalyed
break;

case 9:
Display=0x6F; // '9' is dispalyed
break;
} // switch closed
} // 'for' loop closed

} // while closed
} // main function closed

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