TwiLiquidCrystal.cpp

/*
  Library created in February 2021
  by Arnaud Ouvrier (http://www.arnaudouvrier.fr)

  This is free and unencumbered software released into the public domain.
  For more information, see http://unlicense.org/ or
  the accompanying (un)LICENSE file

  https://github.com/arnakazim/TwiLiquidCrystal-library
*/

#include "Arduino.h"
#include "Wire.h"
#include "TwiLiquidCrystal.h"

TwiLiquidCrystal::TwiLiquidCrystal(uint8_t address) {
  _i2cLcdAddress = address;
}

void TwiLiquidCrystal::setRowOffsets(int row1, int row2, int row3, int row4) {
  _rowOffsets[0] = row1;
  _rowOffsets[1] = row2;
  _rowOffsets[2] = row3;
  _rowOffsets[3] = row4;
}

// write a byte to the I2C bus
size_t TwiLiquidCrystal::write(uint8_t byte) {
  _ctrlRegister |= RS_BIT; // Set register to DATA
  sendCmd(byte);
  _ctrlRegister &= ~RS_BIT; // Reset register to INSTRUCTION

  return 1;
}

void TwiLiquidCrystal::send(uint8_t byte) {
  Wire.beginTransmission(_i2cLcdAddress);
  Wire.write(byte);
  Wire.endTransmission();
}

// Set the state of a bit in the Control register
void TwiLiquidCrystal::setCtrlRegisterBit(uint8_t bit, bool state) {
  if(state) _ctrlRegister |= bit;
  else _ctrlRegister &= ~bit;
}

void TwiLiquidCrystal::setDsplRegisterBit(uint8_t bit, bool state) {
  if(state) _dsplRegister |= bit;
  else _dsplRegister &= ~bit;
}

void TwiLiquidCrystal::setEntryModeBit(uint8_t bit, bool state) {
  if(state) _modeRegister |= bit;
  else _modeRegister &= ~bit;
}

// Merge the command quartet with the control command (BL EN RW RS)
void TwiLiquidCrystal::sendQuartet(uint8_t data) {
  data |= _ctrlRegister;

  send(data);
  send(data | EN_BIT); // pulse enable
  delayMicroseconds(1);
  send(data);
  delayMicroseconds(42);
}

// Take a command byte and split it in two quartets (LCD in 4 bit mode)
void TwiLiquidCrystal::sendCmd(uint8_t data) {
  sendQuartet(data & DATA_PORTION);
  sendQuartet((data << 4) & DATA_PORTION);
}

// Initialization routine to set the LCD to 4 bit mode
void TwiLiquidCrystal::initializationRoutine() {
  // Init in 8-bit
  // LiquidCrystal was outputing 0x30 4500µs - 0x30 4500µs 0x30 150µs
  // The datasheet for the HD44780  says 0x30 4100µs - 0x30 100µs 0x30 no delay...
  // (HD44780U datasheet, page 45)
  // It also may be optionnal, useful only when "the power supply conditions for correctly operating the internal reset circuit are not met"
  sendQuartet(LCD_FUNCTIONSET | LCD_FUNCTIONSET_DL_BIT);
  delayMicroseconds(4200);
  sendQuartet(LCD_FUNCTIONSET | LCD_FUNCTIONSET_DL_BIT); 
  delayMicroseconds(110);
  sendQuartet(LCD_FUNCTIONSET | LCD_FUNCTIONSET_DL_BIT); 

  // set in 4-bit mode (Function set)
  sendQuartet(LCD_FUNCTIONSET);
}

void TwiLiquidCrystal::setBacklight(bool state) {
  setCtrlRegisterBit(BL_BIT, state);
  send(_ctrlRegister);
}

// set the function register
// bytemode = 0 -> 4-bit mode; twoLines = 1 -> 2 lines; font = 0 -> 5x8 dots, 1 = 5x10
void TwiLiquidCrystal::setFctnRegister(uint8_t bytemode, uint8_t twoLines, uint8_t font) {
  _fctnRegister = 0 | (bytemode << 4) | (twoLines << 3) | (font << 2);
  sendCmd(LCD_FUNCTIONSET | _fctnRegister);
}

void TwiLiquidCrystal::setDsplControl(uint8_t display, uint8_t cursor, uint8_t blink) {
  _dsplRegister = 0 | (display << 2) | (cursor << 1) | blink;
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}

void TwiLiquidCrystal::setEntryMode(uint8_t increment, uint8_t shift) {
  _modeRegister = 0 | (increment << 1) | shift;
  sendCmd(LCD_ENTRYMODESET | _modeRegister);
}

void TwiLiquidCrystal::setCursor(uint8_t col, uint8_t row) {
  if ((row >= _rows) | (row >= 4)) {
    row = _rows - 1; 
  }
	sendCmd(LCD_SETDDRAMADDR | (col + _rowOffsets[row]));
}

// Clear the display
void TwiLiquidCrystal::clear() {
  sendCmd(LCD_CLEARDISPLAY);
  delay(2);
}

// Set cursor to 0;0 position
void TwiLiquidCrystal::home() {
  sendCmd(LCD_RETURNHOME);
  delay(2);
}

// Setting up and initializig the LCD 
void TwiLiquidCrystal::begin(uint8_t cols, uint8_t rows, uint8_t font) {
  Wire.begin();

  _cols = cols;
  _rows = rows;
  _font = font;

  // set rows start address
  // On a 16x2:
  //  line 1, screen 1 [0x00 ; 0x0F]
  //  line 2, screen 1 [0x40 ; 0x4F]
  //  line 1, screen 2 [0x10 ; 0x1F]
  //  line 2, screen 2 [0x50 ; 0x5F]
  // On a 20x4 (only one screen, HD44780 can only store 80 characters):
  // (Remark: on a 20x4, incrementing the cursor col give this result:
  //   Line 1 -> Line 3 -> Line 2 -> Line 4)
  //  line 1, screen 1 [0x00 ; 0x13]
  //  line 2, screen 1 [0x40 ; 0x53]
  //  line 3, screen 1 [0x14 ; 0x27]
  //  line 4, screen 1 [0x54 ; 0x67]
  setRowOffsets(0x00, 0x40, 0x00 + cols, 0x40 + cols);

  
  delay(1000); // LCD power up time

  send(0x00); // clear data line
  initializationRoutine();

  // first params(byte) = 0 -> Always 4bit
  setFctnRegister(0, (rows != 1), font);

  clear();
  setDsplControl(1, 0, 0);
  setEntryMode(1, 0);
  home();
}

void TwiLiquidCrystal::createChar(uint8_t index, uint8_t character[]) {
    index &= 0x7; // 7 editable characters

    sendCmd(LCD_SETCGRAMADDR | (index << 3));
    _ctrlRegister |= RS_BIT; // Set register to DATA
    for (uint8_t i=0; i<8; i++) {
      sendCmd(character[i]);
    }
    _ctrlRegister &= ~RS_BIT; // Reset register to INSTRUCTION
}

void TwiLiquidCrystal::selectScreen(uint8_t index) {
  home();

  for (uint8_t i = 0; i < index * _cols; i++) {
    sendCmd(LCD_CURSORSHIFT | LCD_CURSORSHIFT_SC_BIT);
  }
}

void TwiLiquidCrystal::backlight() {
  setBacklight(true);
}

void TwiLiquidCrystal::noBacklight() {
  setBacklight(false);
}

void TwiLiquidCrystal::display() {
  setDsplRegisterBit(LCD_DISPLAYCONTROL_D_BIT, true);
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}

void TwiLiquidCrystal::noDisplay() {
  setDsplRegisterBit(LCD_DISPLAYCONTROL_D_BIT, false);
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}

void TwiLiquidCrystal::blink(){
  setDsplRegisterBit(LCD_DISPLAYCONTROL_B_BIT, true);
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}
    
void TwiLiquidCrystal::noBlink() {
  setDsplRegisterBit(LCD_DISPLAYCONTROL_B_BIT, false);
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}

void TwiLiquidCrystal::cursor() {
  setDsplRegisterBit(LCD_DISPLAYCONTROL_C_BIT, true);
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}

void TwiLiquidCrystal::noCursor() {
  setDsplRegisterBit(LCD_DISPLAYCONTROL_C_BIT, false);
  sendCmd(LCD_DISPLAYCONTROL | _dsplRegister);
}

void TwiLiquidCrystal::leftToRight() {
  setEntryModeBit(LCD_ENTRYMODESET_ID_BIT, true);
  sendCmd(LCD_ENTRYMODESET | _modeRegister);
}

// This is for text that flows Right to Left
void TwiLiquidCrystal::rightToLeft() {
  setEntryModeBit(LCD_ENTRYMODESET_ID_BIT, false);
  sendCmd(LCD_ENTRYMODESET | _modeRegister);
}

void TwiLiquidCrystal::autoscroll(void) {
  setEntryModeBit(LCD_ENTRYMODESET_S_BIT, true);
  sendCmd(LCD_ENTRYMODESET | _modeRegister);
}

// This will 'left justify' text from the cursor
void TwiLiquidCrystal::noAutoscroll(void) {
  setEntryModeBit(LCD_ENTRYMODESET_S_BIT, false);
  sendCmd(LCD_ENTRYMODESET | _modeRegister);
}

void TwiLiquidCrystal::scrollDisplayLeft(void) {
  sendCmd(LCD_CURSORSHIFT | LCD_CURSORSHIFT_SC_BIT);
}

void TwiLiquidCrystal::scrollDisplayRight(void) {
  sendCmd(LCD_CURSORSHIFT | LCD_CURSORSHIFT_RL_BIT | LCD_CURSORSHIFT_SC_BIT);
}

void TwiLiquidCrystal::command(uint8_t value) {
  sendCmd(value);
}