Segments_From_Serial.ino

/*
 Controlling large 7-segment displays via serial
 By: Nathan Seidle, SparkFun Electronics
 Modified: Alasdair Allan, Babilim Light Industries
 
 Original: February 25th, 2015
 Modifications: February 3rd, 2017
 
 License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).

 Here's how to hook up the Arduino pins to the Large Digit Driver IN

 Arduino pin 6 -> CLK (Green on the 6-pin cable)
 5 -> LAT (Blue)
 7 -> SER on the IN side (Yellow)
 5V -> 5V (Orange)
 Power Arduino with 12V and connect to Vin -> 12V (Red)
 GND -> GND (Black)

 There are two connectors on the Large Digit Driver. 'IN' is the input side that should be connected to
 your microcontroller (the Arduino). 'OUT' is the output side that should be connected to the 'IN' of addtional
 digits.

 Each display will use about 150mA with all segments and decimal point on.

*/

#include <EEPROM.h>

byte segmentClock = 6;
byte segmentLatch = 5;
byte segmentData = 7;
String readString;

int addr = 0;

void setup() {
  Serial.begin(9600);
  Serial.println("Network Counter");

  pinMode(segmentClock, OUTPUT);
  pinMode(segmentData, OUTPUT);
  pinMode(segmentLatch, OUTPUT);

  digitalWrite(segmentClock, LOW);
  digitalWrite(segmentData, LOW);
  digitalWrite(segmentLatch, LOW);

  int n = EEPROM.read(addr);
  showNumber(n);

}

void loop() {
  while (Serial.available()) {
    char c = Serial.read();  
    readString += c; 
    delay(2); 
  }
  if (readString.length() >0) {
    Serial.println(readString);  
    int n = readString.toInt();  
    showNumber(n);
    EEPROM.update(addr, n);
    readString = "";
  }
}

void showNumber(float value) {
  int number = abs(value); 

  for (byte x = 0 ; x < 2 ; x++) {
    int remainder = number % 10;
    postNumber(remainder, false);
    number /= 10;
  }

  digitalWrite(segmentLatch, LOW);
  digitalWrite(segmentLatch, HIGH); 
}

void postNumber(byte number, boolean decimal) {

#define a  1<<0
#define b  1<<6
#define c  1<<5
#define d  1<<4
#define e  1<<3
#define f  1<<1
#define g  1<<2
#define dp 1<<7

  byte segments;

  switch (number) {
    case 1: segments = b | c; break;
    case 2: segments = a | b | d | e | g; break;
    case 3: segments = a | b | c | d | g; break;
    case 4: segments = f | g | b | c; break;
    case 5: segments = a | f | g | c | d; break;
    case 6: segments = a | f | g | e | c | d; break;
    case 7: segments = a | b | c; break;
    case 8: segments = a | b | c | d | e | f | g; break;
    case 9: segments = a | b | c | d | f | g; break;
    case 0: segments = a | b | c | d | e | f; break;
    case ' ': segments = 0; break;
    case 'c': segments = g | e | d; break;
    case '-': segments = g; break;
  }

  if (decimal) segments |= dp;

  for (byte x = 0 ; x < 8 ; x++) {
    digitalWrite(segmentClock, LOW);
    digitalWrite(segmentData, segments & 1 << (7 - x));
    digitalWrite(segmentClock, HIGH); 
  }
}