path: root/libraries/LiquidCrystal/LiquidCrystal.cpp

#include "LiquidCrystal.h"

#include <stdio.h>
#include <string.h>
#include "WProgram.h"

// 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).

// This library has been modified to be compatible with the LeafLabs Maple;
// very conservative timing is used due to problems with delayMicroseconds()
// that should be fixed in the 0.0.7 release of the libmaple. [bnewbold]

LiquidCrystal::LiquidCrystal(uint8 rs, uint8 rw, uint8 enable,
                             uint8 d0, uint8 d1, uint8 d2, uint8 d3,
                             uint8 d4, uint8 d5, uint8 d6, uint8 d7)
{
  init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}

LiquidCrystal::LiquidCrystal(uint8 rs, uint8 enable,
                             uint8 d0, uint8 d1, uint8 d2, uint8 d3,
                             uint8 d4, uint8 d5, uint8 d6, uint8 d7)
{
  init(0, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}

LiquidCrystal::LiquidCrystal(uint8 rs, uint8 rw, uint8 enable,
                             uint8 d0, uint8 d1, uint8 d2, uint8 d3)
{
  init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}

LiquidCrystal::LiquidCrystal(uint8 rs,  uint8 enable,
                             uint8 d0, uint8 d1, uint8 d2, uint8 d3)
{
  init(1, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}

void LiquidCrystal::init(uint8 fourbitmode, uint8 rs, uint8 rw, uint8 enable,
                         uint8 d0, uint8 d1, uint8 d2, uint8 d3,
                         uint8 d4, uint8 d5, uint8 d6, uint8 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;

  for (int i = 0; i < 8 - fourbitmode * 4; i++) {
      pinMode(_data_pins[i], OUTPUT);
  }

  pinMode(_rs_pin, OUTPUT);
  // we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
  if (_rw_pin != 255) {
    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;

  // TODO: bnewbold, re-enable this?
  begin(16, 1);
}

void LiquidCrystal::begin(uint8 cols, uint8 lines, uint8 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
  delay(50);    // Maple mod
  //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 != 255) {
    digitalWrite(_rw_pin, LOW);
  }

  //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);
    delay(5);   // Maple mod
    //delayMicroseconds(4500); // wait min 4.1ms

    // second try
    write4bits(0x03);
    delay(5);   // Maple mod
    //delayMicroseconds(4500); // wait min 4.1ms

    // third go!
    write4bits(0x03);
    delay(1);   // Maple mod
    //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);
    delay(5);   // Maple mod
    //delayMicroseconds(4500);  // wait more than 4.1ms

    // second try
    command(LCD_FUNCTIONSET | _displayfunction);
    delay(1);   // Maple mod
    //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 LiquidCrystal::clear()
{
  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
  delay(2);     // Maple mod
  //delayMicroseconds(2000);  // this command takes a long time!
}

void LiquidCrystal::home()
{
  command(LCD_RETURNHOME);  // set cursor position to zero
  delay(2);     // Maple mod
  //delayMicroseconds(2000);  // this command takes a long time!
}

void LiquidCrystal::setCursor(uint8 col, uint8 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 LiquidCrystal::noDisplay() {
  _displaycontrol &= ~LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal::display() {
  _displaycontrol |= LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

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

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

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

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

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

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

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

// Allows us to fill the first 8 CGRAM locations
// with custom characters
void LiquidCrystal::createChar(uint8 location, uint8 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 LiquidCrystal::command(uint8 value) {
  send(value, LOW);
}

inline void LiquidCrystal::write(uint8 value) {
  send(value, HIGH);
}

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

// write either command or data, with automatic 4/8-bit selection
void LiquidCrystal::send(uint8 value, uint8 mode) {
  digitalWrite(_rs_pin, mode);

  // if there is a RW pin indicated, set it low to Write
  if (_rw_pin != 255) {
    digitalWrite(_rw_pin, LOW);
  }

  if (_displayfunction & LCD_8BITMODE) {
    write8bits(value);
  } else {
    write4bits(value>>4);
    write4bits(value);
  }
}

void LiquidCrystal::pulseEnable(void) {
  // _enable_pin should already be LOW (unless someone else messed
  // with it), so don't sit around waiting for long.
  digitalWrite(_enable_pin, LOW);
  delayMicroseconds(1);

  // Enable pulse must be > 450 ns.  Value chosen here according to
  // the following threads:
  // http://forums.leaflabs.com/topic.php?id=640
  // http://forums.leaflabs.com/topic.php?id=512
  togglePin(_enable_pin);
  delayMicroseconds(1);
  togglePin(_enable_pin);

  // Commands needs > 37us to settle.
  delayMicroseconds(42);
}

void LiquidCrystal::write4bits(uint8 value) {
  for (int i = 0; i < 4; i++) {
    digitalWrite(_data_pins[i], (value >> i) & 0x01);
  }

  pulseEnable();
}

void LiquidCrystal::write8bits(uint8 value) {
  for (int i = 0; i < 8; i++) {
    digitalWrite(_data_pins[i], (value >> i) & 0x01);
  }

  pulseEnable();
}