177 lines
6.3 KiB
C++
177 lines
6.3 KiB
C++
// ---------------------------------------------------------------------------
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// Created by Francisco Malpartida on 20/08/11.
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// Copyright 2011 - Under creative commons license 3.0:
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// Attribution-ShareAlike CC BY-SA
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//
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// This software is furnished "as is", without technical support, and with no
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// warranty, express or implied, as to its usefulness for any purpose.
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//
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// Thread Safe: No
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// Extendable: Yes
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//
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// @file LiquidCrystal_SR.h
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// Connects an LCD using 2 or 3 pins from the Arduino, via an 8-bit
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// ShiftRegister (SR from now on).
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//
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// @brief
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// This is a port of the ShiftRegLCD library from raron and ported to the
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// LCD library.
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//
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// The functionality provided by this class and its base class is identical
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// to the original functionality of the Arduino LiquidCrystal library and can
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// be used as such.
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//
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// Modified to work serially with the shiftOut() function, an 8-bit
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// unlatched, no-tristate, unidirectional SIPO (Serial-In-Parallel-Out)
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// shift register (IE a very simple SR), and an LCD in 4-bit mode.
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// Any such shift register should do (pref. 74LS family IC's for 2-wire).
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// I used 74LS164, for the reason that's what I had at hand.
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//
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// Connection description:
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//
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// SR output:
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// Bit #0 - N/C - not connected, used to hold a zero
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// Bit #1 - N/C
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// Bit #2 - connects to RS (Register Select) on the LCD
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// Bits #3-6 - connects to LCD data inputs D4 - D7.
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// Bit #7 - enables the LCD enable-puls (via the diode-resistor AND "gate")
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//
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// 2 or 3 Pins required from the Arduino for Data, Clock and (optional) Enable
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// If not using Enable, the Data pin will be used for the enable signal.
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// 2 wire mode can be indicated by:
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// - ommitting the enable pin in constructor
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// - defining the same pin for Enable as for Data in constructor
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// - by using the token TWO_WIRE for the enable pin.
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//
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// Data and Clock outputs/pins goes to the shiftregister.
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// LCD RW-pin hardwired to LOW (only writing to LCD).
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// Busy Flag (BF, data bit D7) is not read.
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//
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// Original project homepage: http://code.google.com/p/arduinoshiftreglcd/
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//
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//
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// History
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// 2012.03.29 bperrybap - can now eliminate enable pin in constructor for two wire mode.
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// 2011.10.29 fmalpartida - adaption of the library to the LCD class hierarchy.
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// 2011.07.02 Fixed a minor flaw in setCursor function. No functional change,
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// just a bit more memory efficient.
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// Thanks to CapnBry (from google code and github) who noticed it.
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// URL to his version of shiftregLCD:
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// https://github.com/CapnBry/HeaterMeter/commit/c6beba1b46b092ab0b33bcbd0a30a201fd1f28c1
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// 2009.07.30 raron - minor corrections to the comments.
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// Fixed timing to datasheet safe. Fixed keyword highlights.
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// 2009.07.28 Mircho / raron - a new modification to the schematics, and a
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// more streamlined interface
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// 2009.07.27 Thanks to an excellent suggestion from mircho at the Arduiono
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// playgrond forum, the number of wires now required is only two!
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// 2009.07.25 raron - Fixed comments. I really messed up the comments before
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// posting this, so I had to fix it.
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// Renamed a function, but no improvements or functional changes.
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// 2009.07.23 Incorporated some proper initialization routines
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// inspired (lets say copy-paste-tweaked) from LiquidCrystal
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// library improvements from LadyAda.
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// 2009.05.23 raron - first version, but based mostly (as in almost verbatim)
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// on the "official" LiquidCrystal library.
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//
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//
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//
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// @author F. Malpartida - fmalpartida@gmail.com
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// ---------------------------------------------------------------------------
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#ifndef _LIQUIDCRYSTAL_SR_
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#define _LIQUIDCRYSTAL_SR_
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#include <inttypes.h>
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#include "LCD.h"
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#include "FastIO.h"
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// two-wire indicator constant
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// ---------------------------------------------------------------------------
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#define TWO_WIRE 204
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#define SR_RS_BIT 0x04
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#define SR_EN_BIT 0x80
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class LiquidCrystal_SR : public LCD
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{
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public:
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/*!
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@method
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@abstract LCD SHIFT REGISTER constructors.
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@discussion Defines the pin assignment that the LCD will have.
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The constructor does not initialize the LCD. Assuming 1 line 8 pixel high
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font.
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@param srdata[in] pin for shiftregister data line.
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@param srclock[in] pin for shiftregister clock line.
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@param enable[in] optional direct enable pin for the LCD
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*/
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LiquidCrystal_SR ( uint8_t srdata, uint8_t srclock, uint8_t enable=TWO_WIRE );
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/*!
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@function
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@abstract Send a particular value to the LCD.
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@discussion Sends a particular value to the LCD for writing to the LCD or
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as an LCD command using the shift register.
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Users should never call this method.
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@param value[in] Value to send to the LCD.
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@result mode LOW - write to the LCD CGRAM, HIGH - write a command to
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the LCD.
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*/
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virtual void send(uint8_t value, uint8_t mode);
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/*!
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@function
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@abstract Sets the pin to control the backlight.
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@discussion Sets the pin in the device to control the backlight.
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@warning Currently not supported
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@param mode: backlight mode (HIGH|LOW)
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@param pol: backlight polarity
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*/
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void setBacklightPin ( uint8_t pin, t_backlighPol pol );
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/*!
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@function
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@abstract Switch-on/off the LCD backlight.
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@discussion Switch-on/off the LCD backlight.
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The setBacklightPin has to be called before setting the backlight for
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this method to work. @see setBacklightPin.
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@param mode: backlight mode (HIGH|LOW)
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*/
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void setBacklight ( uint8_t mode );
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private:
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/*!
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@method
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@abstract Initializes the LCD pin allocation
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@discussion Initializes the LCD pin allocation and configuration.
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*/
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void init ( uint8_t srdata, uint8_t srclock, uint8_t enable, uint8_t lines,
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uint8_t font );
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/*!
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* @method
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* @abstract takes care of shifting and the enable pulse
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*/
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void shiftIt (uint8_t val);
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uint8_t _enable_pin; // Enable Pin
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uint8_t _two_wire; // two wire mode
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fio_register _srDataRegister; // Serial Data pin
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fio_bit _srDataBit;
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fio_register _srClockRegister; // Clock Pin
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fio_bit _srClockBit;
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fio_register _srEnableRegister; // Enable Pin
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fio_bit _srEnableBit;
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};
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#endif
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