//Author: Vivekanand Dhakane
//updated on: 10 June 2020
//https://oledtutorials.blogspot.com/2020/06/tutorial-2-using-glcd-font-creator-for.html
#include <Wire.h>

#define OLED_I2c_ADDRESS       0x3d//   0x3C
// registers Addresses
#define COMMAND_REG    0x80  // B1000 0000
#define DATA_REG       0x40  // B0100 0000
// commands
#define ON_CMD                0xAF
#define NORMAL_DISPLAY_CMD    0xA6//  INVERT B/W = 0xA7
#define PAGE_ADDRESSING_MODE  0x02 //

#define Char_Verticle_Pages_Required 2
#define Char_Horizontal_Columns_Required 16

/*
//---- 2LINE CHESS BOARD -----
  byte data[] = {0x33, 0x33, 0x33, 0x33, 0xCC, 0xCC, 0xCC,
               0xCC, 0x33, 0x33, 0x33, 0x33, 0xCC, 0xCC,
               0xCC, 0xCC, 0x33, 0x33, 0x33, 0x33, 0xCC,
               0xCC, 0xCC, 0xCC, 0x33, 0x33, 0x33, 0x33,
               0xCC, 0xCC, 0xCC, 0xCC };
//===================
*/

//---------- Big 2 ------------
 byte data[] = {0x0D, 0x00, 0x00, 0x00, 0x00, 0x0C, 0xE0, 0x0E, 0xF0, 
                0x06, 0xF8, 0x03, 0xFC, 0x03, 0xDC, 0x03, 0xCE, 0x03,
                0xC7, 0x03, 0xC3, 0x83, 0xC3, 0xFF, 0xC1, 0x7E, 0xC0,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00};


//================= 
void setup() {
  oled_begin();
  setCursor(0, 0);

  //send data in array to display
  for (int j = 0; j < Char_Horizontal_Columns_Required; j++)  //
  {

    for (int i = 0; i < Char_Verticle_Pages_Required; i++)  //(int i = 0; i < Char_Verticle_Pages_Required; i++)
    {
      setCursor(j, i);
      writeData(data[j * Char_Verticle_Pages_Required + i]);  //writeData(data[j * Char_Verticle_Pages_Required + i]);
    }
  }
}


void loop() {
  // put your main code here, to run repeatedly:

}

void oled_begin()
{
  Wire.begin(); // join i2c bus (address optional for master)
  turnON();
  NormalDisplayMode();
  setPageMode();
  writeCommand(0x8d); //Charge Pump
  writeCommand(0x14);
  clearFullDisplay();
}


void writeCommand(byte command) {
  Wire.beginTransmission(OLED_I2c_ADDRESS); // begin transmitting  (OLED_I2c_ADDRESS=0x3C)
  Wire.write(COMMAND_REG);                  // Command Reg Address (COMMAND_REG     =0x80 )
  Wire.write(command);                      // Command to be excuted
  Wire.endTransmission();                   // stop transmitting
}

void writeData(byte data) {
  Wire.beginTransmission(OLED_I2c_ADDRESS); // begin transmitting   (OLED_I2c_ADDRESS=0x3C)
  Wire.write(DATA_REG);                     //Data Reg Address      (DATA_REG        =0x40)
  Wire.write(data);                         //Write data
  Wire.endTransmission();                   // stop transmitting
}

void turnON() {
  writeCommand(ON_CMD);
}
void NormalDisplayMode() {

  writeCommand(NORMAL_DISPLAY_CMD);

}

void setPageMode() {
  byte addressingMode = PAGE_ADDRESSING_MODE;
  writeCommand(0x20);        //set addressing mode
  writeCommand(PAGE_ADDRESSING_MODE);   //set page addressing mode
}



//clearFullDisplay()
// In this function we are setting X,Y=0
// then write data on 128 column and
// then change page and do same till 7th page
void clearFullDisplay() {
  for (byte page = 0; page < 8; page++) {

    setCursor(0, page);
    for (byte column = 0; column < 128; column++) { //clear all columns
      writeData(0x00);
    }

  }
  setCursor(0, 0);
}

void setCursor(byte X, byte Y) {
  writeCommand(0x00 + (X & 0x0F));        //set column lower address
  writeCommand(0x10 + ((X >> 4) & 0x0F)); //set column higher address
  writeCommand(0xB0 + Y);                 //set page address

}