lctech_8digit_7segment_display.ino

//Written for the M5StackC but should work for other micro-controller
//For the LCTECH 8 digit - 7 segment display module
//Finally found a picture of how it is wired, from
//https://libstock.mikroe.com/projects/view/3860/lctech-74hc164-dual-seven-segments-display-demo-max-min-thermometer
//and found a little more information on the 74c164 shift register from here
//http://www.bristolwatch.com/arduino/arduino3.htm
//with a little trial and error I was finally able to get this to work
//thou it is not perfect, and still needs some work it's a start
//Nov 15, 2020 - LeRoy Miller, KD8BXP (c)


int dataPin = 26;
int clockPin = 0;

//This display appears to be inverted, so a 1 is off, and a 0 is on for this list and only this list
byte digit = 0b00000001; // Not used in this sketch, right bit is the lower right display
//this tells which digit to use starting on the lower display right most display is #0 the top left display is #7

byte zero = 0b00000011; //zero no dot
byte one  = 0b10011111; //one no dot
byte two  = 0b00100101; //two no dot
byte three= 0b00001101; //three no dot
byte four = 0b10011001; //four no dot
byte five = 0b01001001; //five no dot
byte six  = 0b11000001; //six no dot
byte seven= 0b00011111; //seven no dot
byte eight= 0b00000001; //eight no dot
byte nine = 0b00011001; //nine no dot

//               ABCDEFGP
void setup() {
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
}

void loop() {

  //Another way to display (used when testing)
 // shiftOut(dataPin, clockPin, LSBFIRST, zero); //segment);
 //shiftOut(dataPin, clockPin, LSBFIRST, digit);
 
 for (int i=0; i<=7; i++) {
  for (int y=0; y<=9; y++) {
    display(y, i, 0); //display(# between 0 & 9, the digit starting on lower display 0 is the right digit, display dot true/false 0,1)
    delay(150);
  }
 }
 
 //Biggest problem with this display, there is no latch, so to display
 //more than one digit you have to continue to write to the display
 //This is just a test to show it, but a better way is needed to do
 
 while(1) {
 display(1,3,0);
 delay(5);
 display(2,2,1);
 delay(5);
 display(4,1,0);
 delay(5);
 display(1,0,0);
 delay(5);
 display(3,7,true);
 delay(5);
 display(1,6,false);
 delay(5);
 display(4,5,false);
 delay(5);
 display(1,4,false);
 delay(5);
 }
 
}

void display(int segment, int numerial, bool dot) {
  switch (segment) {
    case 0:
    if (dot == 1) {bitWrite(zero, 0, 0); } else {bitWrite(zero,0,1);}
        shiftOut(dataPin, clockPin, LSBFIRST, zero); //segment);
    break;
    case 1:
    if (dot == 1) {bitWrite(one, 0, 0); } else {bitWrite(one,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, one); //segment);
    break;
    case 2:
    if (dot == 1) {bitWrite(two, 0, 0); } else {bitWrite(two,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, two); //segment);
    break;
    case 3:
    if (dot == 1) {bitWrite(three, 0, 0); } else {bitWrite(three,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, three); //segment);
    break;
    case 4:
    if (dot == 1) {bitWrite(four, 0, 0); } else {bitWrite(four,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, four); //segment);
    break;
    case 5:
    if (dot == 1) {bitWrite(five, 0, 0); } else {bitWrite(five,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, five); //segment);
    break;
    case 6:
    if (dot == 1) {bitWrite(six, 0, 0); } else {bitWrite(six,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, six); //segment);
    break;
    case 7:
    if (dot == 1) {bitWrite(seven, 0, 0); } else {bitWrite(seven,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, seven); //segment);
    break;
    case 8:
    if (dot == 1) {bitWrite(eight, 0, 0); } else {bitWrite(eight,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, eight); //segment);
    break;
    case 9:
    if (dot == 1) {bitWrite(nine, 0, 0); } else {bitWrite(nine,0,1);}
    shiftOut(dataPin, clockPin, LSBFIRST, nine); //segment);
    break;
    default:
    //nothing
    break;
  }
  shiftOut(dataPin, clockPin, LSBFIRST, 0b00000001 << numerial); // digit);
}