I have got a simple 4 digit LED display routine. This is simulated using Proteus simulator. So in the picture you see simplified version of circuit. In real world you might need to strobe digits using transistor keys. Control program is written using WinAVR tool chain.
Bellow is a complete C file
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#include
#include
#include
#include
#include
#include
uint8_t numbers[]={
0b11000000,//0
0b11111001,//1
0b10100100,//2
0b10110000,//3
0b10011001,//4
0b10010010,//5
0b10000010,//6
0b11111000,//7
0b10000000,//8
0b10010000,//9
0b01111111//.
};
uint8_t i;
void initAmega8()
{
PORTD=0xFF; //Port D all to “1″ – LEDS OFF
DDRD=0xFF; //Port D all to output
//Port B control lines to “1″ – Transistors OFF
PORTB &=~((1<<<<
//Port B control lines as output
DDRB |=((1<<<<
}
void sendNumber(uint8_t digit, uint8_t position)
{
//0…9 for digit; 1..4 for position
PORTD=numbers[digit];
PORTB|=_BV(position-1);
_delay_us(100);
PORTB&=~_BV(position-1);
_delay_us(100);
}
int main(void)
{
initAmega8();
while(1)
{
sendNumber(2,1);//LCD display shows “2006″
sendNumber(0,2);
sendNumber(0,3);
sendNumber(6,4);
}
return 0;
}
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