// --------------------------------------------------------------------------- // Created by Francisco Malpartida on 20/08/11. // Copyright 2011 - Under creative commons license 3.0: // Attribution-ShareAlike CC BY-SA // // This software is furnished "as is", without technical support, and with no // warranty, express or implied, as to its usefulness for any purpose. // // Thread Safe: No // Extendable: Yes // // @file LiquidCrystal.cpp // This file implements a basic liquid crystal library that comes as standard // in the Arduino SDK. // // @brief // This is a basic implementation of the LiquidCrystal library of the // Arduino SDK. The original library has been reworked in such a way that // this class implements the all methods to command an LCD based // on the Hitachi HD44780 and compatible chipsets using the parallel port of // the LCD (4 bit and 8 bit). // // The functionality provided by this class and its base class is identical // to the original functionality of the Arduino LiquidCrystal library. // // // @author F. Malpartida - fmalpartida@gmail.com // --------------------------------------------------------------------------- #include #include #include #if (ARDUINO < 100) #include #else #include #endif #include "LiquidCrystal.h" // CONSTANT definitions // --------------------------------------------------------------------------- #define LCD_NOBACKLIGHT 0xFF // LCD driver configuration (4bit or 8bit driver control) #define LCD_4BIT 1 #define LCD_8BIT 0 // STATIC helper functions // --------------------------------------------------------------------------- // CONSTRUCTORS // --------------------------------------------------------------------------- LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7) { init(LCD_8BIT, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7); } LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7) { init(LCD_8BIT, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7); } LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3) { init(LCD_4BIT, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0); } LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3) { init(LCD_4BIT, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0); } // Contructors with backlight control LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7, uint8_t backlightPin, t_backlighPol pol) { init(LCD_8BIT, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7); setBacklightPin ( backlightPin, pol ); } LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7, uint8_t backlightPin, t_backlighPol pol) { init(LCD_8BIT, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7); setBacklightPin ( backlightPin, pol ); } LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t backlightPin, t_backlighPol pol) { init(LCD_4BIT, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0); setBacklightPin ( backlightPin, pol ); } LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t backlightPin, t_backlighPol pol) { init(LCD_4BIT, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0); setBacklightPin ( backlightPin, pol ); } // PUBLIC METHODS // --------------------------------------------------------------------------- /************ low level data pushing commands **********/ // // send void LiquidCrystal::send(uint8_t value, uint8_t mode) { // Only interested in COMMAND or DATA digitalWrite( _rs_pin, ( mode == DATA ) ); // if there is a RW pin indicated, set it low to Write // --------------------------------------------------- if (_rw_pin != 255) { digitalWrite(_rw_pin, LOW); } if ( mode != FOUR_BITS ) { if ( (_displayfunction & LCD_8BITMODE ) ) { writeNbits(value, 8); } else { writeNbits ( value >> 4, 4 ); writeNbits ( value, 4 ); } } else { writeNbits ( value, 4 ); } waitUsec ( EXEC_TIME ); // wait for the command to execute by the LCD } // // setBacklightPin void LiquidCrystal::setBacklightPin ( uint8_t pin, t_backlighPol pol ) { pinMode ( pin, OUTPUT ); // Difine the backlight pin as output _backlightPin = pin; _polarity = pol; setBacklight(BACKLIGHT_OFF); // Set the backlight low by default } // // setBackligh void LiquidCrystal::setBacklight ( uint8_t value ) { // Check if there is a pin assigned to the backlight // --------------------------------------------------- if ( _backlightPin != LCD_NOBACKLIGHT ) { // Check if the pin is associated to a timer, i.e. PWM // --------------------------------------------------- if(digitalPinToTimer(_backlightPin) != NOT_ON_TIMER) { // Check for control polarity inversion // --------------------------------------------------- if ( _polarity == POSITIVE ) { analogWrite ( _backlightPin, value ); } else { analogWrite ( _backlightPin, 255 - value ); } } // Not a PWM pin, set the backlight pin for POSI or NEG // polarity // -------------------------------------------------------- else if (((value > 0) && (_polarity == POSITIVE)) || ((value == 0) && (_polarity == NEGATIVE))) { digitalWrite( _backlightPin, HIGH); } else { digitalWrite( _backlightPin, LOW); } } } // PRIVATE METHODS // --------------------------------------------------------------------------- // init void LiquidCrystal::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7) { uint8_t i; // Initialize the IO pins // ----------------------- _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; // Initialize the IO port direction to OUTPUT // ------------------------------------------ for ( i = 0; i < 4; i++ ) { pinMode ( _data_pins[i], OUTPUT ); } // Initialize the rest of the ports if it is an 8bit controlled LCD // ---------------------------------------------------------------- if ( !fourbitmode ) { for ( i = 4; i < 8; 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); // Initialise displaymode functions to defaults: LCD_1LINE and LCD_5x8DOTS // ------------------------------------------------------------------------- if (fourbitmode) _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS; else _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS; // 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); } // Initialise the backlight pin no nothing _backlightPin = LCD_NOBACKLIGHT; _polarity = POSITIVE; } // // pulseEnable void LiquidCrystal::pulseEnable(void) { // There is no need for the delays, since the digitalWrite operation // takes longer. digitalWrite(_enable_pin, HIGH); waitUsec(1); // enable pulse must be > 450ns digitalWrite(_enable_pin, LOW); } // // write4bits void LiquidCrystal::writeNbits(uint8_t value, uint8_t numBits) { for (uint8_t i = 0; i < numBits; i++) { digitalWrite(_data_pins[i], (value >> i) & 0x01); } pulseEnable(); }