Wim Huiskamp
Updated for more display types. Fixed memoryaddress confusion in address() method. Added new getAddress() method. Added support for UDCs, Backlight control and other features such as control through I2C and SPI port expanders and controllers with native I2C and SPI interfaces. Refactored to fix issue with pins that are default declared as NC.
Dependents: GPSDevice TestTextLCD SD to Flash Data Transfer DrumMachine ... more
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TextLCD
by 
Simon Ford
Example
Hello World! for the TextLCD
#include "mbed.h"
#include "TextLCD.h"
// Host PC Communication channels
Serial pc(USBTX, USBRX); // tx, rx
// I2C Communication
I2C i2c_lcd(p28,p27); // SDA, SCL
// SPI Communication
SPI spi_lcd(p5, NC, p7); // MOSI, MISO, SCLK
//TextLCD lcd(p15, p16, p17, p18, p19, p20); // RS, E, D4-D7, LCDType=LCD16x2, BL=NC, E2=NC, LCDTCtrl=HD44780
//TextLCD_SPI lcd(&spi_lcd, p8, TextLCD::LCD40x4); // SPI bus, 74595 expander, CS pin, LCD Type
TextLCD_I2C lcd(&i2c_lcd, 0x42, TextLCD::LCD20x4); // I2C bus, PCF8574 Slaveaddress, LCD Type
//TextLCD_I2C lcd(&i2c_lcd, 0x42, TextLCD::LCD16x2, TextLCD::WS0010); // I2C bus, PCF8574 Slaveaddress, LCD Type, Device Type
//TextLCD_SPI_N lcd(&spi_lcd, p8, p9); // SPI bus, CS pin, RS pin, LCDType=LCD16x2, BL=NC, LCDTCtrl=ST7032_3V3
//TextLCD_I2C_N lcd(&i2c_lcd, ST7032_SA, TextLCD::LCD16x2, NC, TextLCD::ST7032_3V3); // I2C bus, Slaveaddress, LCD Type, BL=NC, LCDTCtrl=ST7032_3V3
int main() {
pc.printf("LCD Test. Columns=%d, Rows=%d\n\r", lcd.columns(), lcd.rows());
for (int row=0; row<lcd.rows(); row++) {
int col=0;
pc.printf("MemAddr(Col=%d, Row=%d)=0x%02X\n\r", col, row, lcd.getAddress(col, row));
// lcd.putc('-');
lcd.putc('0' + row);
for (col=1; col<lcd.columns()-1; col++) {
lcd.putc('*');
}
pc.printf("MemAddr(Col=%d, Row=%d)=0x%02X\n\r", col, row, lcd.getAddress(col, row));
lcd.putc('+');
}
// Show cursor as blinking character
lcd.setCursor(TextLCD::CurOff_BlkOn);
// Set and show user defined characters. A maximum of 8 UDCs are supported by the HD44780.
// They are defined by a 5x7 bitpattern.
lcd.setUDC(0, (char *) udc_0); // Show |>
lcd.putc(0);
lcd.setUDC(1, (char *) udc_1); // Show <|
lcd.putc(1);
}
Handbook page
More info is here
TextLCD.cpp
- Committer:
- wim
- Date:
- 2013-02-10
- Revision:
- 14:0c32b66b14b8
- Parent:
- 13:24506ba22480
- Child:
- 15:b70ebfffb258
File content as of revision 14:0c32b66b14b8:
/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
* Copyright (c) 2007-2010, sford, http://mbed.org
* 2013, v01: WH, Added LCD types, fixed LCD address issues, added Cursor and UDCs
* 2013, v02: WH, Added I2C and SPI bus interfaces
*
* 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.
*/
#include "TextLCD.h"
#include "mbed.h"
TextLCD::TextLCD(PinName rs, PinName e,
PinName d4, PinName d5, PinName d6, PinName d7,
LCDType type): _rs(rs), _e(e),
_d(d4, d5, d6, d7),
_cs(NC),
_type(type) {
_busType = _PinBus;
_init();
}
TextLCD::TextLCD(I2C *i2c, char deviceAddress, LCDType type) :
_rs(NC), _e(NC), _d(NC),
_cs(NC),
_i2c(i2c),
_type(type) {
_slaveAddress = deviceAddress;
_busType = _I2CBus;
// Init the portexpander bus
_lcd_bus = 0x80;
// write the new data to the portexpander
_i2c->write(_slaveAddress, &_lcd_bus, 1);
_init();
}
TextLCD::TextLCD(SPI *spi, PinName cs, LCDType type) :
_rs(NC), _e(NC), _d(NC),
_spi(spi),
_cs(cs),
_type(type) {
_busType = _SPIBus;
// Setup the spi for 8 bit data, low steady state clock,
// rising edge capture, with a 500KHz or 1MHz clock rate
_spi->format(8,0);
_spi->frequency(500000);
//_spi.frequency(1000000);
// Init the portexpander bus
_lcd_bus = 0x80;
// write the new data to the portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
_init();
}
/* Init the LCD controller
* 4-bit mode, number of lines, no cursor etc
* Clear display
*/
void TextLCD::_init() {
// _e = 1;
// _rs = 0; // command mode
_setEnable(true);
_setRS(false); // command mode
// wait(0.015); // Wait 15ms to ensure powered up
wait_ms(15); // 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);
// wait(0.00164); // this command takes 1.64ms, so wait for it
wait_ms(10); // this command takes 1.64ms, so wait for it
}
_writeByte(0x2); // 4-bit mode
// wait(0.000040f); // most instructions take 40us
wait_us(40); // most instructions take 40us
// Display is now in 4-bit mode
switch (_type) {
case LCD8x1:
_writeCommand(0x20); // Function set 001 BW N F - -
// N=0 (1 line)
// F=0 (5x7 dots font)
break;
case LCD24x4:
// Special mode for KS0078
_writeCommand(0x2A); // Function set 001 BW N RE DH REV
// N=1 (Dont care for KS0078)
// RE=0 (Extended Regs, special mode for KS0078)
// DH=1 (Disp shift, special mode for KS0078)
// REV=0 (Reverse, special mode for KS0078)
_writeCommand(0x2E); // Function set 001 BW N RE DH REV
// N=1 (Dont care for KS0078)
// RE=1 (Ena Extended Regs, special mode for KS0078)
// DH=1 (Disp shift, special mode for KS0078)
// REV=0 (Reverse, special mode for KS0078)
_writeCommand(0x09); // Ext Function set 0000 1 FW BW NW
// FW=0 (5-dot font, special mode for KS0078)
// BW=0 (Cur BW invert disable, special mode for KS0078)
// NW=1 (4 Line, special mode for KS0078)
_writeCommand(0x2A); // Function set 001 BW N RE DH REV
// N=1 (Dont care for KS0078)
// RE=0 (Dis. Extended Regs, special mode for KS0078)
// DH=1 (Disp shift, special mode for KS0078)
// REV=0 (Reverse, special mode for KS0078)
break;
default:
_writeCommand(0x28); // Function set 001 BW N F - -
// N=1 (2 lines)
// F=0 (5x7 dots font)
// - (Don't care)
break;
}
_writeCommand(0x06); // Entry Mode 0000 01 CD S
// Cursor Direction and Display Shift
// CD=1 (Cur incr)
// S=0 (No display shift)
// _writeCommand(0x0C); // Display Ctrl 0000 1 D C B
// // Display On, Cursor Off, Blink Off
setCursor(TextLCD::CurOff_BlkOff);
cls();
}
void TextLCD::_character(int column, int row, int c) {
int addr = getAddress(column, row);
_writeCommand(0x80 | addr);
_writeData(c);
}
void TextLCD::cls() {
_writeCommand(0x01); // cls, and set cursor to 0
// wait(0.00164f); // This command takes 1.64 ms
wait_ms(10); // The CLS command takes 1.64 ms.
// Since we are not using the Busy flag, Lets be safe and take 10 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::_setEnable(bool value) {
switch(_busType) {
case _PinBus :
if (value)
_e = 1; // Set E bit
else
_e = 0; // Reset E bit
break;
case _I2CBus :
if (value)
_lcd_bus |= D_LCD_E; // Set E bit
else
_lcd_bus &= ~D_LCD_E; // Reset E bit
// write the new data to the portexpander
_i2c->write(_slaveAddress, &_lcd_bus, 1);
break;
case _SPIBus :
if (value)
_lcd_bus |= D_LCD_E; // Set E bit
else
_lcd_bus &= ~D_LCD_E; // Reset E bit
// write the new data to the portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
break;
}
}
void TextLCD::_setRS(bool value) {
switch(_busType) {
case _PinBus :
if (value)
_rs = 1; // Set RS bit
else
_rs = 0; // Reset RS bit
break;
case _I2CBus :
if (value)
_lcd_bus |= D_LCD_RS; // Set RS bit
else
_lcd_bus &= ~D_LCD_RS; // Reset RS bit
// write the new data to the portexpander
_i2c->write(_slaveAddress, &_lcd_bus, 1);
break;
case _SPIBus :
if (value)
_lcd_bus |= D_LCD_RS; // Set RS bit
else
_lcd_bus &= ~D_LCD_RS; // Reset RS bit
// write the new data to the portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
break;
}
}
void TextLCD::_setData(int value) {
int data;
switch(_busType) {
case _PinBus :
_d = value & 0x0F; // Write Databits
break;
case _I2CBus :
data = value & 0x0F;
if (data & 0x01)
_lcd_bus |= D_LCD_D4; // Set Databit
else
_lcd_bus &= ~D_LCD_D4; // Reset Databit
if (data & 0x02)
_lcd_bus |= D_LCD_D5; // Set Databit
else
_lcd_bus &= ~D_LCD_D5; // Reset Databit
if (data & 0x04)
_lcd_bus |= D_LCD_D6; // Set Databit
else
_lcd_bus &= ~D_LCD_D6; // Reset Databit
if (data & 0x08)
_lcd_bus |= D_LCD_D7; // Set Databit
else
_lcd_bus &= ~D_LCD_D7; // Reset Databit
// write the new data to the portexpander
_i2c->write(_slaveAddress, &_lcd_bus, 1);
break;
case _SPIBus :
data = value & 0x0F;
if (data & 0x01)
_lcd_bus |= D_LCD_D4; // Set Databit
else
_lcd_bus &= ~D_LCD_D4; // Reset Databit
if (data & 0x02)
_lcd_bus |= D_LCD_D5; // Set Databit
else
_lcd_bus &= ~D_LCD_D5; // Reset Databit
if (data & 0x04)
_lcd_bus |= D_LCD_D6; // Set Databit
else
_lcd_bus &= ~D_LCD_D6; // Reset Databit
if (data & 0x08)
_lcd_bus |= D_LCD_D7; // Set Databit
else
_lcd_bus &= ~D_LCD_D7; // Reset Databit
// write the new data to the portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
break;
}
}
// Set CS line. Only used for SPI bus
void TextLCD::_setCS(bool value) {
if (value)
_cs = 1; // Set CS pin
else
_cs = 0; // Reset CS pin
}
void TextLCD::_writeByte(int value) {
// _d = value >> 4;
_setData(value >> 4);
// wait(0.000040f); // most instructions take 40us
wait_us(40); // most instructions take 40us
// _e = 0;
_setEnable(false);
// wait(0.000040f);
wait_us(40); // most instructions take 40us
// _e = 1;
_setEnable(true);
// _d = value >> 0;
_setData(value >> 0);
// wait(0.000040f);
wait_us(40); // most instructions take 40us
// _e = 0;
_setEnable(false);
// wait(0.000040f); // most instructions take 40us
wait_us(40); // most instructions take 40us
// _e = 1;
_setEnable(true);
}
void TextLCD::_writeCommand(int command) {
// _rs = 0;
_setRS(false);
_writeByte(command);
}
void TextLCD::_writeData(int data) {
// _rs = 1;
_setRS(true);
_writeByte(data);
}
#if (0)
// This is the original method.
// It is confusing since it returns the memoryaddress or-ed with the set memorycommand 0x80.
// Left it in here for compatibility with older code. New applications should use getAddress() instead.
//
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;
}
}
#endif
// This replaces the original method.
// Left it in here for compatibility with older code. New applications should use getAddress() instead.
int TextLCD::_address(int column, int row) {
return 0x80 | getAddress(column, row);
}
// This is new method to return the memory address based on row, column and displaytype.
//
int TextLCD::getAddress(int column, int row) {
switch (_type) {
case LCD8x1:
return 0x00 + column;
case LCD16x1:
// LCD16x1 is a special layout of LCD8x2
if (column<8)
return 0x00 + column;
else
return 0x40 + (column - 8);
case LCD16x4:
switch (row) {
case 0:
return 0x00 + column;
case 1:
return 0x40 + column;
case 2:
return 0x10 + column;
case 3:
return 0x50 + column;
}
case LCD20x4:
switch (row) {
case 0:
return 0x00 + column;
case 1:
return 0x40 + column;
case 2:
return 0x14 + column;
case 3:
return 0x54 + column;
}
// Special mode for KS0078
case LCD24x4:
switch (row) {
case 0:
return 0x00 + column;
case 1:
return 0x20 + column;
case 2:
return 0x40 + column;
case 3:
return 0x60 + column;
}
// Not sure about this one, seems wrong.
case LCD16x2B:
return 0x00 + (row * 40) + column;
case LCD8x2:
case LCD16x2:
case LCD20x2:
case LCD24x2:
case LCD40x2:
return 0x00 + (row * 0x40) + column;
// Should never get here.
default:
return 0x00;
}
}
// Added for consistency. Set row, column and update memoryaddress.
//
void TextLCD::setAddress(int column, int row) {
locate(column, row);
int addr = getAddress(column, row);
_writeCommand(0x80 | addr);
}
int TextLCD::columns() {
switch (_type) {
case LCD8x1:
case LCD8x2:
return 8;
case LCD16x1:
case LCD16x2:
case LCD16x2B:
case LCD16x4:
return 16;
case LCD20x2:
case LCD20x4:
return 20;
case LCD24x2:
case LCD24x4:
return 24;
case LCD40x2:
return 40;
// Should never get here.
default:
return 0;
}
}
int TextLCD::rows() {
switch (_type) {
case LCD8x1:
case LCD16x1:
return 1;
case LCD8x2:
case LCD16x2:
case LCD16x2B:
case LCD20x2:
case LCD24x2:
case LCD40x2:
return 2;
case LCD16x4:
case LCD20x4:
case LCD24x4:
return 4;
// Should never get here.
default:
return 0;
}
}
void TextLCD::setCursor(TextLCD::LCDCursor show) {
switch (show) {
case CurOff_BlkOff : _writeCommand(0x0C); // Cursor off and Blink Off
wait_us(40);
_cursor = show;
break;
case CurOn_BlkOff : _writeCommand(0x0E); // Cursor on and Blink Off
wait_us(40);
_cursor = show;
break;
case CurOff_BlkOn : _writeCommand(0x0D); // Cursor off and Blink On
wait_us(40);
_cursor = show;
break;
case CurOn_BlkOn : _writeCommand(0x0F); // Cursor on and Blink char
wait_us(40);
_cursor = show;
break;
// Should never get here.
default :
break;
}
}
void TextLCD::setUDC(unsigned char c, char *udc_data) {
_writeCommand(0x40 + ((c & 0x07) << 3)); //Set CG-RAM address
for (int i=0; i<8; i++) {
_writeData(*udc_data++);
}
}
HD44780 and compatible Text LCD controllers (4bit, I2C or SPI I/F)