/*  Dot matrix control Scrolling
    Tutorial: https://www.electronoobs.com/eng_arduino_tut56.php
    Schematic: https://www.electronoobs.com/eng_arduino_tut56_sch1.php
    LedControl library: https://www.electronoobs.com/eng_arduino_ledcontrol.php
*/

#include <LedControl.h>   //LedControl library: https://www.electronoobs.com/ledcontrol.php
#include "charLUT.h"

const int numDevices = 4;      // number of MAX7219s used
const long scrollDelay = 40;   // adjust scrolling speed
unsigned long bufferLong [14] = {0};
const unsigned char scrollText[] PROGMEM = {"     Hello World !!!     "};

LedControl lc = LedControl(11, 13, 10, numDevices); // DATA | CLK | CS/LOAD | number of matrices

// for test, scrolls entire font list
void scrollFont() {
  for (int counter = 0x20; counter < 0x80; counter++) {
    loadBufferLong(counter);
    delay(50);
  }
}

// Scroll Message
void scrollMessage(const unsigned char * messageString) {
  int counter = 0;
  int myChar = 0;
  do {
    // read back a char
    myChar =  pgm_read_byte_near(messageString + counter);
    if (myChar != 0) {
      loadBufferLong(myChar);
    }
    counter++;
  }
  while (myChar != 0);
}

// Load character into scroll buffer
void loadBufferLong(int ascii) {
  if (ascii >= 0x20 && ascii <= 0x7F) {
    for (int a = 0; a < 7; a++) {               // Loop 7 times for a 5x7 font
      unsigned long c = pgm_read_byte_near(font5x7 + ((ascii - 0x20) * 8) + a);     // Index into character table to get row data
      unsigned long x = bufferLong [a * 2];   // Load current scroll buffer
      x = x | c;                              // OR the new character onto end of current
      bufferLong [a * 2] = x;                 // Store in buffer
    }
    byte count = pgm_read_byte_near(font5x7 + ((ascii - 0x20) * 8) + 7);    // Index into character table for kerning data
    for (byte x = 0; x < count; x++) {
      rotateBufferLong();
      printBufferLong();
      delay(scrollDelay);
    }
  }
}

// Rotate the buffer
void rotateBufferLong() {
  for (int a = 0; a < 7; a++) {             // Loop 7 times for a 5x7 font
    unsigned long x = bufferLong [a * 2];   // Get low buffer entry
    byte b = bitRead(x, 31);                // Copy high order bit that gets lost in rotation
    x = x << 1;                             // Rotate left one bit
    bufferLong [a * 2] = x;                 // Store new low buffer
    x = bufferLong [a * 2 + 1];             // Get high buffer entry
    x = x << 1;                             // Rotate left one bit
    bitWrite(x, 0, b);                      // Store saved bit
    bufferLong [a * 2 + 1] = x;             // Store new high buffer
  }
}

// Display Buffer on LED matrix
void printBufferLong() {
  for (int a = 0; a < 7; a++) {             // Loop 7 times for a 5x7 font
    unsigned long x = bufferLong [a * 2 + 1]; // Get high buffer entry
    byte y = x;                             // Mask off first character
    lc.setRow(3, a, y);                     // Send row to relevent MAX7219 chip
    x = bufferLong [a * 2];                 // Get low buffer entry
    y = (x >> 24);                          // Mask off second character
    lc.setRow(2, a, y);                     // Send row to relevent MAX7219 chip
    y = (x >> 16);                          // Mask off third character
    lc.setRow(1, a, y);                     // Send row to relevent MAX7219 chip
    y = (x >> 8);                           // Mask off forth character
    lc.setRow(0, a, y);                     // Send row to relevent MAX7219 chip
  }
}

void setup()  {
  for (int x = 0; x < numDevices; x++)  {
    lc.shutdown(x, false);      //The MAX72XX is in power-saving mode on startup
    lc.setIntensity(x, 8);      // Set the brightness to default value
    lc.clearDisplay(x);         // and clear the display
  }
}

void loop() {
  scrollMessage(scrollText);
  //scrollFont();
}