thomas ya
for
Dependents: LV_FGSE_Controller_Interface
TextLCD.cpp
- Committer:
- wim
- Date:
- 2013-03-09
- Revision:
- 18:bd65dc10f27f
- Parent:
- 17:652ab113bc2e
- Child:
- 19:c747b9e2e7b8
File content as of revision 18:bd65dc10f27f:
/* 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
* 2013, v03: WH, Added support for LCD40x4 which uses 2 controllers
* 2013, v04: WH, Added support for Display On/Off, improved 4bit bootprocess
* 2013, v05: WH, Added support for 8x2B, added some UDCs
*
* 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"
/* Create a TextLCD interface for using regular mbed pins
*
* @param rs Instruction/data control line
* @param e Enable line (clock)
* @param d4-d7 Data lines for using as a 4-bit interface
* @param type Sets the panel size/addressing mode (default = LCD16x2)
* @param e2 Enable2 line (clock for second controller, LCD40x4 only)
*/
TextLCD::TextLCD(PinName rs, PinName e,
PinName d4, PinName d5, PinName d6, PinName d7,
LCDType type, PinName e2) : _rs(rs), _e(e), _e2(e2),
_d(d4, d5, d6, d7),
_cs(NC),
_type(type) {
_busType = _PinBus;
_init();
}
/* Create a TextLCD interface using an I2C PC8574 portexpander
*
* @param i2c I2C Bus
* @param deviceAddress I2C slave address (PCF8574)
* @param type Sets the panel size/addressing mode (default = LCD16x2)
*/
TextLCD::TextLCD(I2C *i2c, char deviceAddress, LCDType type) :
_rs(NC), _e(NC), _e2(NC),
_d(NC),
_i2c(i2c),
_cs(NC),
_type(type) {
_slaveAddress = deviceAddress;
_busType = _I2CBus;
// Init the portexpander bus
_lcd_bus = D_LCD_BUS_DEF;
// write the new data to the portexpander
_i2c->write(_slaveAddress, &_lcd_bus, 1);
_init();
}
/* Create a TextLCD interface using an SPI 74595 portexpander
*
* @param spi SPI Bus
* @param cs chip select pin (active low)
* @param type Sets the panel size/addressing mode (default = LCD16x2)
*/
TextLCD::TextLCD(SPI *spi, PinName cs, LCDType type) :
_rs(NC), _e(NC), _e2(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 = D_LCD_BUS_DEF;
// write the new data to the portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
_init();
}
/* Init the LCD Controller(s)
* Clear display
*/
void TextLCD::_init() {
// Select and configure second LCD controller when needed
if(_type==LCD40x4) {
_ctrl=TextLCD::_LCDCtrl_1; // Select 2nd controller
_initCtrl(); // Init 2nd controller
// Secondary LCD controller Clearscreen
_writeCommand(0x01); // cls, and set cursor to 0
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
}
// Select and configure primary LCD controller
_ctrl=TextLCD::_LCDCtrl_0; // Select primary controller
_initCtrl(); // Init primary controller
// Primary LCD controller Clearscreen
_writeCommand(0x01); // cls, and set cursor to 0
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
}
/* Init the LCD controller
* 4-bit mode, number of lines, fonttype, no cursor etc
*
*/
void TextLCD::_initCtrl() {
_setRS(false); // command mode
wait_ms(20); // Wait 20ms to ensure powered up
#if(1)
// send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
for (int i=0; i<3; i++) {
_writeNibble(0x3);
wait_ms(15); // this command takes 1.64ms, so wait for it
}
_writeNibble(0x2); // 4-bit mode
wait_us(40); // most instructions take 40us
#else
//Original code. Does not comply with specification and causes problems
//unless used right after power-on.
// 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_ms(15); // this command takes 1.64ms, so wait for it
}
_writeByte(0x2); // 4-bit mode
wait_us(40); // most instructions take 40us
#endif
// Display is now in 4-bit mode
#if(0)
// ST7036 controller: Initialise Voltage booster for VLCD. VDD=5V
// Note: supports 1,2 or 3 lines
_writeByte( 0x29 ); // 4-bit Databus, 2 Lines, Select Instruction table 1
wait_us(27); // > 26,3ms
_writeByte( 0x14 ); // Bias: 1/5, 2-Lines LCD
wait_us(30); // > 26,3ms
_writeByte( 0x55 ); // Icon off, Booster on, Set Contrast C5, C4
wait_us(30); // > 26,3ms
_writeByte( 0x6d ); // Voltagefollower On, Ampl ratio Rab2, Rab1, Rab0
wait_ms(200); // > 200ms!
_writeByte( 0x78 ); // Set Contrast C3, C2, C1, C0
wait_us(30); // > 26,3ms
_writeByte( 0x28 ); // Return to Instruction table 0
wait_ms(50);
#endif
// Initialise Display configuration
switch (_type) {
case LCD8x1:
case LCD8x2B:
//8x1 is a regular 1 line display
//8x2B is a special case of 16x1
_writeCommand(0x20); // Function set 001 DL N F - -
// DL=0 (4 bits bus)
// N=0 (1 line)
// F=0 (5x7 dots font)
break;
case LCD24x4:
// Special mode for KS0078
_writeCommand(0x2A); // Function set 001 DL N RE DH REV
// DL=0 (4 bits bus)
// 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 DL N RE DH REV
// DL=0 (4 bits bus)
// 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 DL N RE DH REV
// DL=0 (4 bits bus)
// 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;
// All other LCD types are initialised as 2 Line displays (including LCD40x4)
default:
_writeCommand(0x28); // Function set 001 DL N F - -
// DL=0 (4 bits bus)
// N=1 (2 lines)
// F=0 (5x7 dots font, only option for 2 line display)
// - (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);
setMode(TextLCD::DispOn);
}
// Clear the screen, Cursor home.
void TextLCD::cls() {
// Select and configure second LCD controller when needed
if(_type==LCD40x4) {
_ctrl=TextLCD::_LCDCtrl_1; // Select 2nd controller
// Second LCD controller Cursor always Off
_setCursorAndDisplayMode(_currentMode, TextLCD::CurOff_BlkOff);
// Second LCD controller Clearscreen
_writeCommand(0x01); // cls, and set cursor to 0
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
_ctrl=TextLCD::_LCDCtrl_0; // Select primary controller
}
// Primary LCD controller Clearscreen
_writeCommand(0x01); // cls, and set cursor to 0
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
// Restore cursormode on primary LCD controller when needed
if(_type==LCD40x4) {
_setCursorAndDisplayMode(_currentMode,_currentCursor);
}
_row=0; // Reset Cursor location
_column=0;
}
// Move cursor to selected row and column
void TextLCD::locate(int column, int row) {
// setAddress() does all the heavy lifting:
// check column and row sanity,
// switch controllers for LCD40x4 if needed
// switch cursor for LCD40x4 if needed
// set the new memory address to show cursor at correct location
setAddress(column, row);
}
// Write a single character (Stream implementation)
int TextLCD::_putc(int value) {
int addr;
if (value == '\n') {
//No character to write
//Update Cursor
_column = 0;
_row++;
if (_row >= rows()) {
_row = 0;
}
}
else {
//Character to write
_writeData(value);
//Update Cursor
_column++;
if (_column >= columns()) {
_column = 0;
_row++;
if (_row >= rows()) {
_row = 0;
}
}
} //else
//Set next memoryaddress, make sure cursor blinks at next location
addr = getAddress(_column, _row);
_writeCommand(0x80 | addr);
return value;
}
// get a single character (Stream implementation)
int TextLCD::_getc() {
return -1;
}
// Set E pin (or E2 pin)
// Used for mbed pins, I2C bus expander or SPI shifregister
void TextLCD::_setEnable(bool value) {
switch(_busType) {
case _PinBus :
if(_ctrl==TextLCD::_LCDCtrl_0) {
if (value)
_e = 1; // Set E bit
else
_e = 0; // Reset E bit
}
else {
if (value)
_e2 = 1; // Set E2 bit
else
_e2 = 0; // Reset E2 bit
}
break;
case _I2CBus :
if(_ctrl==TextLCD::_LCDCtrl_0) {
if (value)
_lcd_bus |= D_LCD_E; // Set E bit
else
_lcd_bus &= ~D_LCD_E; // Reset E bit
}
else {
if (value)
_lcd_bus |= D_LCD_E2; // Set E2 bit
else
_lcd_bus &= ~D_LCD_E2; // Reset E2bit
}
// write the new data to the I2C portexpander
_i2c->write(_slaveAddress, &_lcd_bus, 1);
break;
case _SPIBus :
if(_ctrl==TextLCD::_LCDCtrl_0) {
if (value)
_lcd_bus |= D_LCD_E; // Set E bit
else
_lcd_bus &= ~D_LCD_E; // Reset E bit
}
else {
if (value)
_lcd_bus |= D_LCD_E2; // Set E2 bit
else
_lcd_bus &= ~D_LCD_E2; // Reset E2 bit
}
// write the new data to the SPI portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
break;
}
}
// Set RS pin
// Used for mbed pins, I2C bus expander or SPI shifregister
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 I2C 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 SPI portexpander
_setCS(false);
_spi->write(_lcd_bus);
_setCS(true);
break;
}
}
// Place the 4bit data on the databus
// Used for mbed pins, I2C bus expander or SPI shifregister
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 I2C 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 SPI 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
}
// Write a nibble using the 4-bit interface
// Used for mbed pins, I2C bus expander or SPI shifregister
void TextLCD::_writeNibble(int value) {
// Enable is Low
_setEnable(true);
_setData(value & 0x0F); // Low nibble
wait_us(1); // Data setup time
_setEnable(false);
wait_us(1); // Datahold time
// Enable is Low
}
// Write a byte using the 4-bit interface
// Used for mbed pins, I2C bus expander or SPI shifregister
void TextLCD::_writeByte(int value) {
// Enable is Low
_setEnable(true);
_setData(value >> 4); // High nibble
wait_us(1); // Data setup time
_setEnable(false);
wait_us(1); // Data hold time
_setEnable(true);
_setData(value >> 0); // Low nibble
wait_us(1); // Data setup time
_setEnable(false);
wait_us(1); // Datahold time
// Enable is Low
}
void TextLCD::_writeCommand(int command) {
_setRS(false);
wait_us(1); // Data setup time for RS
_writeByte(command);
wait_us(40); // most instructions take 40us
}
void TextLCD::_writeData(int data) {
_setRS(true);
wait_us(1); // Data setup time for RS
_writeByte(data);
wait_us(40); // data writes take 40us
}
#if (0)
// This is the original _address() 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 _address() 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 LCD8x2B:
// LCD8x2B is a special layout of LCD16x1
if (row==0)
return 0x00 + column;
else
return 0x08 + column;
case LCD16x1:
// LCD16x1 is a special layout of LCD8x2
if (column<8)
return 0x00 + column;
else
return 0x40 + (column - 8);
case LCD12x4:
switch (row) {
case 0:
return 0x00 + column;
case 1:
return 0x40 + column;
case 2:
return 0x0C + column;
case 3:
return 0x4C + column;
}
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 LCD12x2:
case LCD16x2:
case LCD20x2:
case LCD24x2:
case LCD40x2:
return 0x00 + (row * 0x40) + column;
case LCD40x4:
// LCD40x4 is a special case since it has 2 controllers
// Each controller is configured as 40x2
if (row<2) {
// Test to see if we need to switch between controllers
if (_ctrl != _LCDCtrl_0) {
// Second LCD controller Cursor Off
_setCursorAndDisplayMode(_currentMode, TextLCD::CurOff_BlkOff);
// Select primary controller
_ctrl = _LCDCtrl_0;
// Restore cursormode on primary LCD controller
_setCursorAndDisplayMode(_currentMode, _currentCursor);
}
return 0x00 + (row * 0x40) + column;
}
else {
// Test to see if we need to switch between controllers
if (_ctrl != _LCDCtrl_1) {
// Primary LCD controller Cursor Off
_setCursorAndDisplayMode(_currentMode, TextLCD::CurOff_BlkOff);
// Select secondary controller
_ctrl = _LCDCtrl_1;
// Restore cursormode on secondary LCD controller
_setCursorAndDisplayMode(_currentMode, _currentCursor);
}
return 0x00 + ((row-2) * 0x40) + column;
}
// Should never get here.
default:
return 0x00;
}
}
// Set row, column and update memoryaddress.
//
void TextLCD::setAddress(int column, int row) {
// Sanity Check column
if (column < 0) {
_column = 0;
}
else if (column >= columns()) {
_column = columns() - 1;
} else _column = column;
// Sanity Check row
if (row < 0) {
_row = 0;
}
else if (row >= rows()) {
_row = rows() - 1;
} else _row = row;
// Compute the memory address
// For LCD40x4: switch controllers if needed
// switch cursor if needed
int addr = getAddress(_column, _row);
_writeCommand(0x80 | addr);
}
int TextLCD::columns() {
switch (_type) {
case LCD8x1:
case LCD8x2:
case LCD8x2B:
return 8;
case LCD12x2:
case LCD12x4:
return 12;
case LCD16x1:
case LCD16x2:
case LCD16x2B:
case LCD16x4:
return 16;
case LCD20x2:
case LCD20x4:
return 20;
case LCD24x2:
case LCD24x4:
return 24;
case LCD40x2:
case LCD40x4:
return 40;
// Should never get here.
default:
return 0;
}
}
int TextLCD::rows() {
switch (_type) {
case LCD8x1:
case LCD16x1:
return 1;
case LCD8x2:
case LCD8x2B:
case LCD12x2:
case LCD16x2:
case LCD16x2B:
case LCD20x2:
case LCD24x2:
case LCD40x2:
return 2;
case LCD12x4:
case LCD16x4:
case LCD20x4:
case LCD24x4:
case LCD40x4:
return 4;
// Should never get here.
default:
return 0;
}
}
// Set the Cursor Mode (Cursor Off & Blink Off, Cursor On & Blink Off, Cursor Off & Blink On, Cursor On & Blink On
void TextLCD::setCursor(TextLCD::LCDCursor cursorMode) {
// Save new cursor mode, needed when 2 controllers are in use or when display is switched off/on
_currentCursor = cursorMode;
// Configure only current LCD controller
_setCursorAndDisplayMode(_currentMode, _currentCursor);
}
// Set the Displaymode (On/Off)
void TextLCD::setMode(TextLCD::LCDMode displayMode) {
// Save new displayMode, needed when 2 controllers are in use or when cursor is changed
_currentMode = displayMode;
// Select and configure second LCD controller when needed
if(_type==LCD40x4) {
if (_ctrl==TextLCD::_LCDCtrl_0) {
// Configure primary LCD controller
_setCursorAndDisplayMode(_currentMode, _currentCursor);
// Select 2nd controller
_ctrl=TextLCD::_LCDCtrl_1;
// Configure secondary LCD controller
_setCursorAndDisplayMode(_currentMode, TextLCD::CurOff_BlkOff);
// Restore current controller
_ctrl=TextLCD::_LCDCtrl_0;
}
else {
// Select primary controller
_ctrl=TextLCD::_LCDCtrl_0;
// Configure primary LCD controller
_setCursorAndDisplayMode(_currentMode, TextLCD::CurOff_BlkOff);
// Restore current controller
_ctrl=TextLCD::_LCDCtrl_1;
// Configure secondary LCD controller
_setCursorAndDisplayMode(_currentMode, _currentCursor);
}
}
else {
// Configure primary LCD controller
_setCursorAndDisplayMode(_currentMode, _currentCursor);
}
}
// Set the Displaymode (On/Off) and Cursortype for current controller
void TextLCD::_setCursorAndDisplayMode(TextLCD::LCDMode displayMode, TextLCD::LCDCursor cursorType) {
// Configure current LCD controller
_writeCommand(0x08 | displayMode | cursorType);
}
void TextLCD::setUDC(unsigned char c, char *udc_data) {
// Select and configure second LCD controller when needed
if(_type==LCD40x4) {
_LCDCtrl current_ctrl = _ctrl; // Temp save current controller
// Select primary controller
_ctrl=TextLCD::_LCDCtrl_0;
// Configure primary LCD controller
_setUDC(c, udc_data);
// Select 2nd controller
_ctrl=TextLCD::_LCDCtrl_1;
// Configure secondary LCD controller
_setUDC(c, udc_data);
// Restore current controller
_ctrl=current_ctrl;
}
else {
// Configure primary LCD controller
_setUDC(c, udc_data);
}
}
void TextLCD::_setUDC(unsigned char c, char *udc_data) {
// Select CG RAM for current LCD controller
_writeCommand(0x40 + ((c & 0x07) << 3)); //Set CG-RAM address,
//8 sequential locations needed per UDC
// Store UDC pattern
for (int i=0; i<8; i++) {
_writeData(*udc_data++);
}
//Select DD RAM again for current LCD controller
int addr = getAddress(_column, _row);
_writeCommand(0x80 | addr);
}