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LiquidCrystal_SR3W.h
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LiquidCrystal_SR3W.h
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// ---------------------------------------------------------------------------
// Created by Francisco Malpartida on 7.3.2012.
// 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_SR3W.h
// This file implements a basic liquid crystal library that comes as standard
// in the Arduino SDK but using a generic SHIFT REGISTER extension board.
//
// @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 a 3 wire latching
// shift register. While it has been tested with a 74HC595N shift register
// it should also work with other latching shift registers such as the MC14094
// and the HEF4094
//
// This particular driver has been created as generic as possible to enable
// users to configure and connect their LCDs using just 3 digital IOs from the
// AVR or Arduino, and connect the LCD to the outputs of the shiftregister
// in any configuration. The library is configured by passing the IO pins
// that control the strobe, data and clock of the shift register and a map
// of how the shiftregister is connected to the LCD.
//
//
// +--------------------------------------------+
// | MCU |
// | IO1 IO2 IO3 |
// +----+-------------+-------------+-----------+
// | | |
// | | |
// +----+-------------+-------------+-----------+
// | Strobe Data Clock |
// | 8-bit shift/latch register | 74HC595N
// | Qa0 Qb1 Qc2 Qd3 Qe4 Qf5 Qg6 Qh7 |
// +----+----+----+----+----+----+----+----+----+
// | | | | | | |
// |11 |12 |13 |14 |6 |5 |4 (LCD pins)
// +----+----+----+----+----+----+----+----+----+
// | DB4 DB5 DB6 DB7 E Rw RS |
// | LCD Module |
//
// NOTE: Rw is not used by the driver so it can be connected to GND.
//
// 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
// ---------------------------------------------------------------------------
#ifndef _LIQUIDCRYSTAL_SR3W_H_
#define _LIQUIDCRYSTAL_SR3W_H_
#include <inttypes.h>
#include "LCD.h"
#include "FastIO.h"
class LiquidCrystal_SR3W : public LCD
{
public:
/*!
@method
@abstract Class constructor.
@discussion Initializes class variables and defines the IO driving the
shift register. The constructor does not initialize the LCD.
Default configuration:
Shift register LCD
QA - 0 DB4
QB - 1 DB5
QC - 2 DB6
QD - 3 DB7
QE - 4 E
QF - 5
QG - 6 Rs
GND Rw
@param strobe[in] digital IO connected to shiftregister strobe pin.
@param data[in] digital IO connected to the shiftregister data pin.
@param clk[in] digital IO connected to the shiftregister clock pin.
*/
LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe);
// Constructor with backlight control
LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe,
uint8_t backlighPin, t_backlighPol pol);
/*!
@method
@abstract Class constructor.
@discussion Initializes class variables and defines the control lines of
the LCD and the shiftregister. The constructor does not initialize the LCD.
@param strobe[in] digital IO connected to shiftregister strobe pin.
@param data[in] digital IO connected to shiftregister data pin.
@param clk[in] digital IO connected to shiftregister clock pin.
@param En[in] LCD En (Enable) pin connected to SR output pin.
@param Rw[in] LCD Rw (Read/write) pin connected to SR output pin.
@param Rs[in] LCD Rs (Reg Select) pin connected to SR output pin.
@param d4[in] LCD data 4 pin map to the SR output pin.
@param d5[in] LCD data 5 pin map to the SR output pin.
@param d6[in] LCD data 6 pin map to the SR output pin.
@param d7[in] LCD data 7 pin map to the SR output pin.
*/
LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe,
uint8_t En, uint8_t Rw, uint8_t Rs,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7 );
// Constructor with backlight control
LiquidCrystal_SR3W( uint8_t data, uint8_t clk, uint8_t strobe,
uint8_t En, uint8_t Rw, uint8_t Rs,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7,
uint8_t backlighPin, t_backlighPol pol);
/*!
@function
@abstract Send a particular value to the LCD.
@discussion Sends a particular value to the LCD for writing to the LCD or
as an LCD command.
Users should never call this method.
@param value[in] Value to send to the LCD.
@param mode[in] DATA - write to the LCD CGRAM, COMMAND - write a
command to the LCD.
*/
virtual void send(uint8_t value, uint8_t mode);
/*!
@function
@abstract Sets the pin to control the backlight.
@discussion Sets the pin in the device to control the backlight. This device
doesn't support dimming backlight capability.
@param value: pin mapped on the 74HC595N (0, .., 7) for (Qa0, .., Qh7)
respectively.
@param pol: polarity POSITIVE|NEGATIVE.
*/
void setBacklightPin ( uint8_t value, t_backlighPol pol );
/*!
@function
@abstract Switch-on/off the LCD backlight.
@discussion Switch-on/off the LCD backlight.
The setBacklightPin has to be called before setting the backlight for
this method to work. @see setBacklightPin.
@param value: backlight mode (HIGH|LOW)
*/
void setBacklight ( uint8_t value );
private:
/*!
@method
@abstract Initializes the LCD class
@discussion Initializes the LCD class and IO expansion module.
*/
int init(uint8_t data, uint8_t clk, uint8_t strobe,
uint8_t Rs, uint8_t Rw, uint8_t En,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
/*!
@method
@abstract Writes an 4 bit value to the LCD.
@discussion Writes 4 bits (the least significant) to the LCD control data lines.
@param value[in] Value to write to the LCD
@param more[in] Value to distinguish between command and data.
COMMAND == command, DATA == data.
*/
void write4bits(uint8_t value, uint8_t mode);
/*!
@function
@abstract load into the shift register a byte
@discussion loads into the shift register a byte
@param value[in]: value to be loaded into the shiftregister.
*/
void loadSR(uint8_t value);
fio_bit _strobe; // shift register strobe pin
fio_register _strobe_reg; // SR strobe pin MCU register
fio_bit _data; // shift register data pin
fio_register _data_reg; // SR data pin MCU register
fio_bit _clk; // shift register clock pin
fio_register _clk_reg; // SR clock pin MCU register
uint8_t _En; // LCD expander word for enable pin
uint8_t _Rw; // LCD expander word for R/W pin
uint8_t _Rs; // LCD expander word for Register Select pin
uint8_t _data_pins[4]; // LCD data lines
uint8_t _backlightPinMask; // Backlight IO pin mask
uint8_t _backlightStsMask; // Backlight status mask
};
#endif