test
Dependents: Nucleo_read_analog_value
Diff: TextLCD.cpp
- Revision:
- 0:e6225ada294a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TextLCD.cpp Mon Mar 07 03:37:06 2016 +0000 @@ -0,0 +1,198 @@ +/* mbed I2CTextLCD Library, for a 4-bit LCD driven by I2C and a PCF8574 + * Copyright (c) 2007-2010, sford, rcocking + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +/* This is a hack of Simon Ford's direct-driven TextLCD code. +* It should be refactored to extract a common superclass +* but my C++ isn't yet good enough :) +* +* The code assumes the following connections between the PCF8574 +* and the LCD +* +* nc - D0 +* nc - D1 +* nc - D2 +* nc - D3 +* P0 - D4 +* P1 - D5 +* P2 - D6 +* P3 - D7 +* P4 - E +* P5 - nc +* P6 - nc +* P7 - RS +* gnd - R/W +* +* D0-3 of the LCD are not connected because we work in 4-bit mode +* R/W is hardwired to gound, as we only ever write to the LCD +* A0-2 on the PCF8574 can be set in any combination; you will need to modify +* the I2C address in the I2CTextLCD constructor. +* Remember that the mbed uses 8-bit addresses, which should be +* in the range 0x40-0x4E for the PCF8574 +*/ +#include "TextLCD.h" +#include "mbed.h" + + +TextLCD::TextLCD(PinName sda, PinName scl, int i2cAddress, LCDType type) : _i2c(sda, scl), _i2cAddress(i2cAddress) , _type(type){ + // _i2cAddress = i2cAddress; + writeByte(E_ON,false); + wait(0.015); // Wait 15ms to ensure powered up + + // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus) + for (int i=0; i<3; i++) { + writeByte(0x3, false); + wait(0.00164); // this command takes 1.64ms, so wait for it + } + writeByte(0x2, false); // 4-bit mode + wait(0.000040f); // most instructions take 40us + + writeCommand(0x28); // Function set 001 BW N F - - + writeCommand(0x0C); + writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes + cls(); +} + +void TextLCD::character(int column, int row, int c) { + int a = address(column, row); + writeCommand(a); + writeData(c); +} + +void TextLCD::cls() { + writeCommand(0x01); // cls, and set cursor to 0 + wait(0.00164f); // This command takes 1.64 ms + locate(0, 0); +} + +void TextLCD::locate(int column, int row) { + _column = column; + _row = row; +} + +int TextLCD::_putc(int value) { + if (value == '\n') { + _column = 0; + _row++; + if (_row >= rows()) { + _row = 0; + } + } else { + character(_column, _row, value); + _column++; + if (_column >= columns()) { + _column = 0; + _row++; + if (_row >= rows()) { + _row = 0; + } + } + } + return value; +} + +int TextLCD::_getc() { + return -1; +} + +void TextLCD::writeI2CByte(int data) { + // equivalent to writeI2CByte + char cmd[1]; + cmd[0] = data; + _i2c.write(_i2cAddress, cmd, 1); +} + +void TextLCD::writeNibble(int data, bool rs) { + data = data << 4; + data |= BL_ON; // E on + if (rs) { + data = data | RS_ON; // set rs bit + } + data |= E_ON; // E on + writeI2CByte(data); + data ^= E_ON; // E off + //wait_us(1); + wait(0.000001f); // most instructions take 40us + writeI2CByte(data); + wait(0.001f); // most instructions take 40us + // wait_us(1000); +} + +void TextLCD::writeByte(int data, bool rs) { + writeNibble(data >> 4, rs); + writeNibble(data & 0x0F, rs); +} + +void TextLCD::writeCommand(int command) { + // equivalent to ard commandWrite + writeByte(command, false); +} + +void TextLCD::writeData(int data) { + + writeByte(data, true); +} + +int TextLCD::address(int column, int row) { + switch (_type) { + case LCD20x4: + switch (row) { + case 0: + return 0x80 + column; + case 1: + return 0xc0 + column; + case 2: + return 0x94 + column; + case 3: + return 0xd4 + column; + } + case LCD16x2B: + return 0x80 + (row * 40) + column; + case LCD16x2: + case LCD20x2: + default: + return 0x80 + (row * 0x40) + column; + } +} + +int TextLCD::columns() { + switch (_type) { + case LCD20x4: + case LCD20x2: + return 20; + case LCD16x2: + case LCD16x2B: + default: + return 16; + } +} + +int TextLCD::rows() { + switch (_type) { + case LCD20x4: + return 4; + case LCD16x2: + case LCD16x2B: + case LCD20x2: + default: + return 2; + } +}