This document defines functions for displaying numeric values on a 7-segment display using an Arduino. It sets latch, clock, and data pins as outputs to control the display. The disNum() function takes in a numeric value, position, and decimal flag and outputs the corresponding 7-segment display value. The showNum() function takes a double value, converts it to long, extracts each digit, and calls disNum() to display the number on the 7-segment display one position at a time.

1. int latchPin = 13;//ST_CP
int clockPin = 12;//SH_CP
int dataPin = 11; //DS
// define latch, clock and datapin
void setup ()
{
pinMode(latchPin,OUTPUT);
pinMode(clockPin,OUTPUT);
pinMode(dataPin,OUTPUT);
//set these three pins to output
}
//Display function (display word, display position, display if have
//decimal point)
void disNum(int Num_Qua, int Num_Pos, int Num_Dec)
{
int Num_Qua_B = 0;
int Num_Pos_B = 0;
switch (Num_Qua)
{
case 0:Num_Qua_B = 192;break;
case 1:Num_Qua_B = 249;break;
case 2:Num_Qua_B = 164;break;
case 3:Num_Qua_B = 176;break;
case 4:Num_Qua_B = 153;break;
case 5:Num_Qua_B = 146;break;
case 6:Num_Qua_B = 130;break;
case 7:Num_Qua_B = 248;break;

2. case 8:Num_Qua_B = 128;break;
case 9:Num_Qua_B = 144;break;
default: Num_Qua_B = 255;break;
};
//this value convert to binary, which is adcdefg need to light up
switch (Num_Pos)
{
case 1:Num_Pos_B = 1;break;
case 2:Num_Pos_B = 2;break;
case 3:Num_Pos_B = 4;break;
case 4:Num_Pos_B = 8;break;
case 5:Num_Pos_B = 16;break;
case 6:Num_Pos_B = 32;break;
case 7:Num_Pos_B = 64;break;
case 8:Num_Pos_B = 128;break;
default: Num_Pos_B = 0;break;
};
//this value convert to binary, which is the one light up now.
if (Num_Dec == 1)
{
Num_Qua_B = Num_Qua_B + 128;
};
//========================================
digitalWrite(latchPin,LOW);
// set latch to low tolet the display ready to receive data
int L = Num_Qua_B; int R = Num_Pos_B;
shiftOut(dataPin,clockPin,MSBFIRST,R);
shiftOut(dataPin,clockPin,MSBFIRST,L);

3. digitalWrite(latchPin,HIGH); //restore to high TTL back
//========================================
delayMicroseconds(100);
}
//this is the display number function
void showNum(double number)
// use double instead of int, int is not longer enough
{
long num = number;
int ShowDec [8];
for (int x = 1; x < 9; x++)
{
ShowDec [x] = 0;
}
//creat the array for decimal point, 0 is not to display, 1 is to display
if (num < 10000000){
if (num < 1000000){num = number*100; ShowDec[6]=1;ShowDec[7]=0;}
else{
num = number*10; ShowDec[7]=1;
}
}
//simple decimal point for two number display
int ShowNumber [8];
ShowNumber[1] = (num/10000000)%10;
ShowNumber[2]= (num/1000000)%10;

4. ShowNumber[3] = (num/100000)%10;
ShowNumber[4] = (num/10000)%10;
ShowNumber[5] = (num/1000)%10;
ShowNumber[6] = (num/100)%10;
ShowNumber[7] = (num/10)%10;
ShowNumber[8]= (num/1)%10;
//get every number and store in the arrary
int dectest = 0;
for (int x = 1; x<8; x++)
{
if ((dectest == 0)and(ShowNumber[x] == 0))
{
ShowNumber[x] = 11;
}
else
{
dectest = 1;
}
}
//check if there is a "0" on the left front, if yes we ignore it
disNum(ShowNumber[1],1,ShowDec[1]);
disNum(ShowNumber[2],2,ShowDec[2]);
disNum(ShowNumber[3],3,ShowDec[3]);
disNum(ShowNumber[4],4,ShowDec[4]);

5. disNum(ShowNumber[5],5,ShowDec[5]);
disNum(ShowNumber[6],6,ShowDec[6]);
disNum(ShowNumber[7],7,ShowDec[7]);
disNum(ShowNumber[8],8,ShowDec[8]);
//display number in sequency, flashing fast
}
void loop()
{
showNum(80600000);//simple function to display to number
}