PortsLCD.cpp

#include "PortsLCD.h"
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#if ARDUINO>=100
#include <Arduino.h> // Arduino 1.0
#else
#include <WProgram.h> // Arduino 0022
#endif

void LiquidCrystalBase::begin(byte cols, byte lines, byte dotsize) {
  if (lines > 1) {
    _displayfunction |= LCD_2LINE;
  }
  _numlines = lines;
  _currline = 0;

  // for some 1 line displays you can select a 10 pixel high font
  if ((dotsize != 0) && (lines == 1)) {
    _displayfunction |= LCD_5x10DOTS;
  }

  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
  // according to datasheet, we need at least 40ms after power rises above 2.7V
  // before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
  delayMicroseconds(50000); // can't use delay, may get called before main!

  // Now we pull both RS and R/W low to begin commands
  config();
  
  //put the LCD into 4 bit or 8 bit mode
  if (! (_displayfunction & LCD_8BITMODE)) {
    // this is according to the hitachi HD44780 datasheet
    // figure 24, pg 46

    // we start in 8bit mode, try to set 4 bit mode
    write4bits(0x03);
    delayMicroseconds(4500); // wait min 4.1ms

    // second try
    write4bits(0x03);
    delayMicroseconds(4500); // wait min 4.1ms
    
    // third go!
    write4bits(0x03); 
    delayMicroseconds(150);

    // finally, set to 8-bit interface
    write4bits(0x02); 
  } else {
    // this is according to the hitachi HD44780 datasheet
    // page 45 figure 23

    // Send function set command sequence
    command(LCD_FUNCTIONSET | _displayfunction);
    delayMicroseconds(4500);  // wait more than 4.1ms

    // second try
    command(LCD_FUNCTIONSET | _displayfunction);
    delayMicroseconds(150);

    // third go
    command(LCD_FUNCTIONSET | _displayfunction);
  }

  // finally, set # lines, font size, etc.
  command(LCD_FUNCTIONSET | _displayfunction);  

  // turn the display on with no cursor or blinking default
  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;  
  display();

  // clear it off
  clear();

  // Initialize to default text direction (for romance languages)
  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
  // set the entry mode
  command(LCD_ENTRYMODESET | _displaymode);

}

/********** high level commands, for the user! */
void LiquidCrystalBase::clear()
{
  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
  delayMicroseconds(2000);  // this command takes a long time!
}

void LiquidCrystalBase::home()
{
  command(LCD_RETURNHOME);  // set cursor position to zero
  delayMicroseconds(2000);  // this command takes a long time!
}

void LiquidCrystalBase::setCursor(byte col, byte row)
{
  int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
  if ( row > _numlines ) {
    row = _numlines-1;    // we count rows starting w/0
  }
  
  command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
}

/// Turn the display on/off (quickly)
void LiquidCrystalBase::noDisplay() {
  _displaycontrol &= ~LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystalBase::display() {
  _displaycontrol |= LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

/// Turns the underline cursor on/off
void LiquidCrystalBase::noCursor() {
  _displaycontrol &= ~LCD_CURSORON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystalBase::cursor() {
  _displaycontrol |= LCD_CURSORON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

/// Turn on and off the blinking cursor
void LiquidCrystalBase::noBlink() {
  _displaycontrol &= ~LCD_BLINKON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystalBase::blink() {
  _displaycontrol |= LCD_BLINKON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

/// These commands scroll the display without changing the RAM
void LiquidCrystalBase::scrollDisplayLeft(void) {
  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void LiquidCrystalBase::scrollDisplayRight(void) {
  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}

/// This is for text that flows Left to Right
void LiquidCrystalBase::leftToRight(void) {
  _displaymode |= LCD_ENTRYLEFT;
  command(LCD_ENTRYMODESET | _displaymode);
}

/// This is for text that flows Right to Left
void LiquidCrystalBase::rightToLeft(void) {
  _displaymode &= ~LCD_ENTRYLEFT;
  command(LCD_ENTRYMODESET | _displaymode);
}

/// This will 'right justify' text from the cursor
void LiquidCrystalBase::autoscroll(void) {
  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
  command(LCD_ENTRYMODESET | _displaymode);
}

/// This will 'left justify' text from the cursor
void LiquidCrystalBase::noAutoscroll(void) {
  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
  command(LCD_ENTRYMODESET | _displaymode);
}

/// Allows us to fill the first 8 CGRAM locations
/// with custom characters
void LiquidCrystalBase::createChar(byte location, byte charmap[]) {
  location &= 0x7; // we only have 8 locations 0-7
  command(LCD_SETCGRAMADDR | (location << 3));
  for (int i=0; i<8; i++) {
    write(charmap[i]);
  }
}

/*********** mid level commands, for sending data/cmds */

inline void LiquidCrystalBase::command(byte value) {
  send(value, LOW);
}

inline WRITE_RESULT LiquidCrystalBase::write(byte value) {
  send(value, HIGH);
#if ARDUINO >= 100 && !defined(__AVR_ATtiny84__) && !defined(__AVR_ATtiny85__) && !defined(__AVR_ATtiny44__) && !defined(__AVR_ATtiny45__)
  return 1;
#endif
}

// When the display powers up, it is configured as follows:
//
// 1. Display clear
// 2. Function set: 
//    DL = 1; 8-bit interface data 
//    N = 0; 1-line display 
//    F = 0; 5x8 dot character font 
// 3. Display on/off control: 
//    D = 0; Display off 
//    C = 0; Cursor off 
//    B = 0; Blinking off 
// 4. Entry mode set: 
//    I/D = 1; Increment by 1 
//    S = 0; No shift 
//
// Note, however, that resetting the Arduino doesn't reset the LCD, so we
// can't assume that its in that state when a sketch starts (and the
// LiquidCrystal constructor is called).

LiquidCrystal::LiquidCrystal(byte rs, byte rw, byte enable,
	     byte d0, byte d1, byte d2, byte d3, byte d4, byte d5, byte d6, byte d7)
{
  init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}

LiquidCrystal::LiquidCrystal(byte rs, byte enable,
	     byte d0, byte d1, byte d2, byte d3, byte d4, byte d5, byte d6, byte d7)
{
  init(0, rs, -1, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}

LiquidCrystal::LiquidCrystal(byte rs, byte rw, byte enable,
	     byte d0, byte d1, byte d2, byte d3)
{
  init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}

LiquidCrystal::LiquidCrystal(byte rs,  byte enable,
	     byte d0, byte d1, byte d2, byte d3)
{
  init(1, rs, -1, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}

void LiquidCrystal::init(byte fourbitmode, byte rs, byte rw, byte enable,
			 byte d0, byte d1, byte d2, byte d3, byte d4, byte d5, byte d6, byte d7)
{
  _rs_pin = rs;
  _rw_pin = rw;
  _enable_pin = enable;
  
  _data_pins[0] = d0;
  _data_pins[1] = d1;
  _data_pins[2] = d2;
  _data_pins[3] = d3; 
  _data_pins[4] = d4;
  _data_pins[5] = d5;
  _data_pins[6] = d6;
  _data_pins[7] = d7; 

  pinMode(_rs_pin, OUTPUT);
  // we can save 1 pin by not using RW. Indicate by passing -1 instead of pin#
  if (_rw_pin != -1) { 
    pinMode(_rw_pin, OUTPUT);
  }
  pinMode(_enable_pin, OUTPUT);
  
  if (fourbitmode)
    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
  else 
    _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
  
  begin(16, 1);  
}

/************ low level data pushing commands **********/

void LiquidCrystal::config() {
  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
  // according to datasheet, we need at least 40ms after power rises above 2.7V
  // before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
  delayMicroseconds(50000); 
  // Now we pull both RS and R/W low to begin commands
  digitalWrite(_rs_pin, LOW);
  digitalWrite(_enable_pin, LOW);
  if (_rw_pin != -1) { 
    digitalWrite(_rw_pin, LOW);
  }
}

/// write either command or data, with automatic 4/8-bit selection
void LiquidCrystal::send(byte value, byte mode) {
  digitalWrite(_rs_pin, mode);

  // if there is a RW pin indicated, set it low to Write
  if (_rw_pin != -1) { 
    digitalWrite(_rw_pin, LOW);
  }
  
  if (_displayfunction & LCD_8BITMODE) {
    write8bits(value); 
  } else {
    write4bits(value>>4);
    write4bits(value);
  }
}

void LiquidCrystal::pulseEnable(void) {
  digitalWrite(_enable_pin, LOW);
  delayMicroseconds(1);    
  digitalWrite(_enable_pin, HIGH);
  delayMicroseconds(1);    // enable pulse must be >450ns
  digitalWrite(_enable_pin, LOW);
  delayMicroseconds(100);   // commands need > 37us to settle
}

void LiquidCrystal::write4bits(byte value) {
  for (int i = 0; i < 4; i++) {
    pinMode(_data_pins[i], OUTPUT);
    digitalWrite(_data_pins[i], (value >> i) & 0x01);
  }

  pulseEnable();
}

void LiquidCrystal::write8bits(byte value) {
  for (int i = 0; i < 8; i++) {
    pinMode(_data_pins[i], OUTPUT);
    digitalWrite(_data_pins[i], (value >> i) & 0x01);
  }
  
  pulseEnable();
}

enum {
  MCP_IODIR, MCP_IPOL, MCP_GPINTEN, MCP_DEFVAL, MCP_INTCON, MCP_IOCON,
  MCP_GPPU, MCP_INTF, MCP_INTCAP, MCP_GPIO, MCP_OLAT
};

// bits 0..3 and D4..D7, the rest is connected as follows
#define MCP_BACKLIGHT   0x80
#define MCP_ENABLE      0x40
#define MCP_OTHER       0x20
#define MCP_REGSEL      0x10

LiquidCrystalI2C::LiquidCrystalI2C (const PortI2C& p, byte addr)
    : device (p, addr) {
  _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
  begin(16, 2);  
}

void LiquidCrystalI2C::backlight() {
    device.send();
    device.write(MCP_IODIR);
    device.write(0); // IODIR: all outputs
    device.stop();
}

void LiquidCrystalI2C::noBacklight() {
    device.send();
    device.write(MCP_IODIR);
    device.write(MCP_BACKLIGHT); // IODIR: all outputs, except backlight
    device.stop();
}

/************ low level data pushing commands **********/

void LiquidCrystalI2C::config() {
  // IOCON: SEQOP = 1, ODR = 1, rest zero
  device.send();
  device.write(MCP_IOCON);
  device.write(0x24);
  device.stop();
  backlight(); // start with backlight on
}

/// write either command or data, with automatic 4/8-bit selection
void LiquidCrystalI2C::send(byte value, byte mode) {
  if (mode != 0)
    mode = MCP_REGSEL;
  write4bits((value >> 4) | mode);
  write4bits((value & 0x0F) | mode);
}

void LiquidCrystalI2C::write4bits(byte value) {
  value |= MCP_BACKLIGHT | MCP_ENABLE;
  device.send();
  device.write(MCP_GPIO);
  device.write(value);
  device.write(value ^ MCP_ENABLE);
  device.write(value);
  device.stop();
}