Romilly Cocking
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I2CTextLCD
Driver for a Text LCD using a PCF8574 over I2C
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TextLCD.h
00001 /* mbed TextLCD Library, for a 4-bit LCD based on HD44780 00002 * Copyright (c) 2007-2010, sford 00003 * 00004 * Permission is hereby granted, free of charge, to any person obtaining a copy 00005 * of this software and associated documentation files (the "Software"), to deal 00006 * in the Software without restriction, including without limitation the rights 00007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 00008 * copies of the Software, and to permit persons to whom the Software is 00009 * furnished to do so, subject to the following conditions: 00010 * 00011 * The above copyright notice and this permission notice shall be included in 00012 * all copies or substantial portions of the Software. 00013 * 00014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 00015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 00016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 00017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 00018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 00019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 00020 * THE SOFTWARE. 00021 */ 00022 00023 #ifndef MBED_TEXTLCD_H 00024 #define MBED_TEXTLCD_H 00025 00026 #include "mbed.h" 00027 00028 #define E_ON 0x10 00029 #define RS_ON 0x80 00030 00031 /** A TextLCD interface for driving 4-bit HD44780-based LCDs 00032 * 00033 * Currently supports 16x2, 20x2 and 20x4 panels 00034 * 00035 * @code 00036 * #include "mbed.h" 00037 * #include "TextLCD.h" 00038 * 00039 * TextLCD lcd(p10, p12, p15, p16, p29, p30); // rs, e, d0-d3 00040 * 00041 * int main() { 00042 * lcd.printf("Hello World!\n"); 00043 * } 00044 * @endcode 00045 */ 00046 class TextLCD : public Stream { 00047 public: 00048 00049 /** LCD panel format */ 00050 enum LCDType { 00051 LCD16x2 /**< 16x2 LCD panel (default) */ 00052 , LCD16x2B /**< 16x2 LCD panel alternate addressing */ 00053 , LCD20x2 /**< 20x2 LCD panel */ 00054 , LCD20x4 /**< 20x4 LCD panel */ 00055 }; 00056 00057 /** Create a TextLCD interface 00058 * 00059 * @param rs Instruction/data control line 00060 * @param e Enable line (clock) 00061 * @param d0-d3 Data lines 00062 * @param type Sets the panel size/addressing mode (default = LCD16x2) 00063 */ 00064 TextLCD(PinName sda, PinName scl, int i2cAddress = 0x40, LCDType type = LCD16x2); 00065 00066 #if DOXYGEN_ONLY 00067 /** Write a character to the LCD 00068 * 00069 * @param c The character to write to the display 00070 */ 00071 int putc(int c); 00072 00073 /** Write a formated string to the LCD 00074 * 00075 * @param format A printf-style format string, followed by the 00076 * variables to use in formating the string. 00077 */ 00078 int printf(const char* format, ...); 00079 #endif 00080 00081 /** Locate to a screen column and row 00082 * 00083 * @param column The horizontal position from the left, indexed from 0 00084 * @param row The vertical position from the top, indexed from 0 00085 */ 00086 void locate(int column, int row); 00087 00088 /** Clear the screen and locate to 0,0 */ 00089 void cls(); 00090 00091 int rows(); 00092 int columns(); 00093 00094 protected: 00095 00096 // Stream implementation functions 00097 virtual int _putc(int value); 00098 virtual int _getc(); 00099 00100 int address(int column, int row); 00101 void character(int column, int row, int c); 00102 void writeByte(int value, bool rs); 00103 void writeCommand(int command); 00104 void writeData(int data); 00105 void writeNibble(int value, bool rs); 00106 void writeI2CByte(int data); 00107 00108 LCDType _type; 00109 int _rs; 00110 I2C _i2c; 00111 int _i2cAddress; 00112 00113 int _column; 00114 int _row; 00115 }; 00116 00117 #endif
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