Hey ppl, i need to make a countdown timer with two 7-seg display, that start count at 30 seconds and ends in 0 seconds. What components i will need ?
And any one got ideias how code will be in C Language?

thx for help

 

Just hooked up the 2 7 segment displays to the IO ports of the 8051 via transistor array ULN2803, and the switches to any other IO ports.


unsigned char lookUpTable(unsigned char displayNumber);

void 1SecDelay();

void main(){

// Display 30​

digitTenthPort=lookUpTable(3);​

digitUnitPort=lookUpTable(0);​

if (startSwitch==PRESSED){​

for(x=30;x>-1;x--){​

digitTenthPort=lookUpTable(x/10);​

digitUnitPort=lookUpTable(x%10);​

1SecDelay()​

}​

}​

}

}