Подключение LCD к arduino.
Jan. 23rd, 2014 04:39 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
zepeteПрограммы для arduino пишутся на обычном c++.
Для поддержки lcd там имеется специальный класс LiquidCrystal (LiquidCrystal Library), только он не доработан:
-нет метода аналогичного printf;
-не может читать позицию курсора и символ по конкретным координатам;
-на 4 строчном экране, после вывода на первую строку переходит писать на третью, а после третьей переходит на вторую:)
Для устранения этих недостатков придется редактировать этот класс, ибо производный от него не будет наследовать необходимые переменные (назначение выводов arduino) и функций.
Моя доработка касается только конфигурации с передачей байтов за два прохода по 4 бита (8 битная передача только занимает лишние 4 провода и мне она не нужна) и для четырех строчных экранов по 20 символов, вроде WinStar WEH002004ALPP5N00000.
Файл LCD.cpp
#include "LCD.h"
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "Arduino.h"
const int LCD::row_offsets[4] = {ROW0, ROW1, ROW2, ROW3};
// When the display powers up, it is configured as follows:
//
// 1. Display clear
// 2. Function set:
// DL = 1; 8-bit interface data
// N = 0; 1-line display
// F = 0; 5x8 dot character font
// 3. Display on/off control:
// D = 0; Display off
// C = 0; Cursor off
// B = 0; Blinking off
// 4. Entry mode set:
// I/D = 1; Increment by 1
// S = 0; No shift
//
// Note, however, that resetting the Arduino doesn't reset the LCD, so we
// can't assume that its in that state when a sketch starts (and the
// LCD constructor is called).
LCD::LCD(uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
{
init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}
LCD::LCD(uint8_t rs, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
{
init(0, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}
LCD::LCD(uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
{
init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}
LCD::LCD(uint8_t rs, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
{
init(1, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}
void LCD::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
{
_rs_pin = rs;
_rw_pin = rw;
_enable_pin = enable;
_data_pins[0] = d0;
_data_pins[1] = d1;
_data_pins[2] = d2;
_data_pins[3] = d3;
_data_pins[4] = d4;
_data_pins[5] = d5;
_data_pins[6] = d6;
_data_pins[7] = d7;
pinMode(_rs_pin, OUTPUT);
// we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
if (_rw_pin != 255) {
pinMode(_rw_pin, OUTPUT);
}
pinMode(_enable_pin, OUTPUT);
if (fourbitmode)
_displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
else
_displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
begin(16, 1);
}
void LCD::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
if (lines > 1) {
_displayfunction |= LCD_2LINE;
}
_numlines = lines;
_currline = 0;
// for some 1 line displays you can select a 10 pixel high font
if ((dotsize != 0) && (lines == 1)) {
_displayfunction |= LCD_5x10DOTS;
}
// SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
// according to datasheet, we need at least 40ms after power rises above 2.7V
// before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
delayMicroseconds(50000);
// Now we pull both RS and R/W low to begin commands
digitalWrite(_rs_pin, LOW);
digitalWrite(_enable_pin, LOW);
if (_rw_pin != 255) {
digitalWrite(_rw_pin, LOW);
}
//put the LCD into 4 bit or 8 bit mode
if (! (_displayfunction & LCD_8BITMODE)) {
// this is according to the hitachi HD44780 datasheet
// figure 24, pg 46
// we start in 8bit mode, try to set 4 bit mode
write4bits(0x03);
delayMicroseconds(4500); // wait min 4.1ms
// second try
write4bits(0x03);
delayMicroseconds(4500); // wait min 4.1ms
// third go!
write4bits(0x03);
delayMicroseconds(150);
// finally, set to 4-bit interface
write4bits(0x02);
} else {
// this is according to the hitachi HD44780 datasheet
// page 45 figure 23
// Send function set command sequence
command(LCD_FUNCTIONSET | _displayfunction);
delayMicroseconds(4500); // wait more than 4.1ms
// second try
command(LCD_FUNCTIONSET | _displayfunction);
delayMicroseconds(150);
// third go
command(LCD_FUNCTIONSET | _displayfunction);
}
// finally, set # lines, font size, etc.
command(LCD_FUNCTIONSET | _displayfunction);
// turn the display on with no cursor or blinking default
_displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
display();
// clear it off
clear();
// Initialize to default text direction (for romance languages)
_displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
// set the entry mode
command(LCD_ENTRYMODESET | _displaymode);
}
/********** high level commands, for the user! */
void LCD::clear()
{
command(LCD_CLEARDISPLAY); // clear display, set cursor position to zero
delayMicroseconds(2000); // this command takes a long time!
}
void LCD::home()
{
command(LCD_RETURNHOME); // set cursor position to zero
delayMicroseconds(2000); // this command takes a long time!
}
void LCD::setCursor(uint8_t col, uint8_t row)
{
if ( row >= _numlines ) {
row = _numlines-1; // we count rows starting w/0
}
command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
}
// Turn the display on/off (quickly)
void LCD::noDisplay() {
_displaycontrol &= ~LCD_DISPLAYON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LCD::display() {
_displaycontrol |= LCD_DISPLAYON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
// Turns the underline cursor on/off
void LCD::noCursor() {
_displaycontrol &= ~LCD_CURSORON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LCD::cursor() {
_displaycontrol |= LCD_CURSORON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
// Turn on and off the blinking cursor
void LCD::noBlink() {
_displaycontrol &= ~LCD_BLINKON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LCD::blink() {
_displaycontrol |= LCD_BLINKON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
// These commands scroll the display without changing the RAM
void LCD::scrollDisplayLeft(void) {
command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void LCD::scrollDisplayRight(void) {
command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}
// This is for text that flows Left to Right
void LCD::leftToRight(void) {
_displaymode |= LCD_ENTRYLEFT;
command(LCD_ENTRYMODESET | _displaymode);
}
// This is for text that flows Right to Left
void LCD::rightToLeft(void) {
_displaymode &= ~LCD_ENTRYLEFT;
command(LCD_ENTRYMODESET | _displaymode);
}
// This will 'right justify' text from the cursor
void LCD::autoscroll(void) {
_displaymode |= LCD_ENTRYSHIFTINCREMENT;
command(LCD_ENTRYMODESET | _displaymode);
}
// This will 'left justify' text from the cursor
void LCD::noAutoscroll(void) {
_displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
command(LCD_ENTRYMODESET | _displaymode);
}
// Allows us to fill the first 8 CGRAM locations
// with custom characters
void LCD::createChar(uint8_t location, uint8_t charmap[]) {
location &= 0x7; // we only have 8 locations 0-7
command(LCD_SETCGRAMADDR | (location << 3));
for (int i=0; i<8; i++) {
write(charmap[i]);
}
}
/*********** mid level commands, for sending data/cmds */
inline void LCD::command(uint8_t value) {
send(value, LOW);
}
inline size_t LCD::write(uint8_t value) {
send(value, HIGH);
return 1; // assume sucess
}
/************ low level data pushing commands **********/
// write either command or data, with automatic 4/8-bit selection
void LCD::send(uint8_t value, uint8_t mode) {
digitalWrite(_rs_pin, mode);
// if there is a RW pin indicated, set it low to Write
if (_rw_pin != 255) {
digitalWrite(_rw_pin, LOW);
}
if (_displayfunction & LCD_8BITMODE) {
write8bits(value);
} else {
write4bits(value>>4);
write4bits(value);
}
}
void LCD::pulseEnable(void) {
pulseON();
digitalWrite(_enable_pin, LOW);
delayMicroseconds(100); // commands need > 37us to settle
}
void LCD::write4bits(uint8_t value) {
for (int i = 0; i < 4; i++) {
pinMode(_data_pins[i], OUTPUT);
digitalWrite(_data_pins[i], (value >> i) & 0x01);
}
pulseEnable();
}
void LCD::write8bits(uint8_t value) {
for (int i = 0; i < 8; i++) {
pinMode(_data_pins[i], OUTPUT);
digitalWrite(_data_pins[i], (value >> i) & 0x01);
}
pulseEnable();
}
uint8_t LCD::GetBFlagAndCounter(void)
{
uint8_t value;
// read address counter and busy flag;
digitalWrite(LCD::_rs_pin, LOW);
digitalWrite(_rw_pin, HIGH);
// if (_displayfunction & LCD_8BITMODE)
// return read8bits(value);
value = read4bits()*16;
return value|(read4bits());
}uint8_t LCD::read4bits(void)
{
uint8_t v=0;
int8_t i=0;
for (i = 0; i<4; i++) {
pinMode(_data_pins[i], INPUT);
}
pulseON();
for (i = 3; i>=0; i--) {
v=v*2+digitalRead(_data_pins[i]);
pinMode(_data_pins[i], OUTPUT);
}
digitalWrite(_enable_pin, LOW);
return v;
}void LCD::CharOut(const char c)
{
uint8_t p,l;
// parse char
switch(c)
{
case '\0': // blank char
return;
case '\b': // backspace
p=GetBFlagAndCounter()&0x7f;
switch(p)
{
case 0:
break;
case ROW1:
p=row_offsets[0]+19;
break;
case ROW2:
p=row_offsets[1]+19;
break;
case ROW3:
p=row_offsets[2]+19;
break;
deafult:
p-=1;
}
command(LCD_SETDDRAMADDR |p);
return;
case '\f': // clear screen
command(LCD_CLEARDISPLAY);
while(GetBFlagAndCounter()&0x80);
return;
case '\n': // new line
getCursor(p,l);
if(l<3) // move cursor down
{
l+=1;
setCursor(p,l);
return;
}
// scroll screen up
ScrollUp();
return;
case '\r': // carrige return
getCursor(p,l);
setCursor(0,l);
return;
case '\t': // tab
getCursor(p,l);
p+=4;
p=p/4;
p*=4;
if(p>19)
{
p=0;
l+=1;
}
setCursor(p,l);
return;
case '\v': // line up
getCursor(p,l);
l-=1;
if(l==0xff) l=0;
setCursor(p,l);
return;
default:
// output char to lcd
write(c);
break;
}
// get current address
p=GetBFlagAndCounter()&0x7f;
switch(p)
{
case ROW3:
command(LCD_SETDDRAMADDR |row_offsets[2]);
return;
case ROW2:
command(LCD_SETDDRAMADDR |row_offsets[1]);
return;
case 0:
ScrollUp();
case ROW1:
command(LCD_SETDDRAMADDR |row_offsets[3]);
return;
}
}
void LCD::printf(const char * format, ... )
{
char sz[81];
va_list args;
va_start (args, format);
vsprintf (sz,format, args);
// output buffer to LCD screen
for(char* psz=sz;*psz!=0;psz++)
CharOut(*psz);
}void LCD::pulseON(void) {
digitalWrite(_enable_pin, LOW);
delayMicroseconds(1);
digitalWrite(_enable_pin, HIGH);
delayMicroseconds(1); // enable pulse must be >450ns
}
void LCD::getCursor(uint8_t& col, uint8_t& row)
{
col=GetBFlagAndCounter()&0x7f;
if(col>=ROW3)
{
col-=ROW3;
row=3;
}
else if(col>=ROW1)
{
col-=ROW1;
row=1;
}
else if(col>=ROW2)
{
col-=ROW2;
row=2;
}
else
row=0;
return;
}
void LCD::ScrollUp()
{
uint8_t uOldAddr=GetBFlagAndCounter()&0x7f;
command(LCD_SETDDRAMADDR);
for(int l=1;l<4;l++)
for(int c=0;c<20;c++)
CharOut(getChar(c+row_offsets[l]));
command(LCD_SETDDRAMADDR | ROW3);
for(int c=0;c<20;c++)
write(' ');
command(LCD_SETDDRAMADDR | uOldAddr);
}char LCD::getChar(uint8_t col, uint8_t row)
{
char value;
uint8_t uOldAddr=GetBFlagAndCounter()&0x7f;
// set new adr
setCursor(col,row);
// read value
digitalWrite(LCD::_rs_pin, HIGH);
digitalWrite(_rw_pin, HIGH);
// if (_displayfunction & LCD_8BITMODE)
// return read8bits(value);
value = read4bits()<<4;
value|= read4bits();
command(LCD_SETDDRAMADDR | uOldAddr);
return value;
}
char LCD::getChar(uint8_t addr)
{
// store old addr
char value;
uint8_t uOldAddr=GetBFlagAndCounter()&0x7f;
// set new adr
command(LCD_SETDDRAMADDR | addr);
// read value
digitalWrite(LCD::_rs_pin, HIGH);
digitalWrite(_rw_pin, HIGH);
// if (_displayfunction & LCD_8BITMODE)
// return read8bits(value);
value = read4bits()<<4;
value|= read4bits();
command(LCD_SETDDRAMADDR | uOldAddr);
return value;
}void LCD::setChar(uint8_t addr,char c)
{
// store old addr
uint8_t uOldAddr=GetBFlagAndCounter()&0x7f;
// set new addr
command(LCD_SETDDRAMADDR | addr);
// set value
write(c);
// restore addr
command(LCD_SETDDRAMADDR | uOldAddr);
return;
}void LCD::CharOut_noscroll(const char c)
{
uint8_t p,l;
// parse char
switch(c)
{
case '\0': // blank char
return;
case '\b': // backspace
p=GetBFlagAndCounter()&0x7f;
switch(p)
{
case 0:
break;
case ROW1:
p=row_offsets[0]+19;
break;
case ROW2:
p=row_offsets[1]+19;
break;
case ROW3:
p=row_offsets[2]+19;
break;
deafult:
p-=1;
}
command(LCD_SETDDRAMADDR |p);
return;
case '\f': // clear screen
command(LCD_CLEARDISPLAY);
while(GetBFlagAndCounter()&0x80);
return;
case '\n': // new line
getCursor(p,l);
if(l<3) // move cursor down
{
l+=1;
setCursor(p,l);
return;
}
return;
case '\r': // carrige return
getCursor(p,l);
setCursor(0,l);
return;
case '\t': // tab
getCursor(p,l);
l=p;
p+=4;
p=p/4;
p*=4;
for(p-=l;p;p--)
CharOut(' ');
return;
case '\v': // line up
getCursor(p,l);
l-=1;
if(l==0xff) l=0;
setCursor(p,l);
return;
default:
// output char to lcd
write(c);
break;
}
// get current address
p=GetBFlagAndCounter()&0x7f;
switch(p)
{
case ROW3:
command(LCD_SETDDRAMADDR |ROW2);
return;
case ROW2:
command(LCD_SETDDRAMADDR |ROW1);
return;
case 0:
command(LCD_SETDDRAMADDR |ROW3+19);
return;
case ROW1:
command(LCD_SETDDRAMADDR |ROW3);
return;
}
}void LCD::printf_noscroll(const char * format, ... )
{
char sz[81];
va_list args;
va_start (args, format);
vsprintf (sz,format, args);
// output buffer to LCD screen
for(char* psz=sz;*psz!=0;psz++)
CharOut_noscroll(*psz);
}
Файл LCD.h
#ifndef LiquidCrystal_h
#define LiquidCrystal_h
#include <inttypes.h>
#include "Print.h"
// адреса начала строк
#define ROW0 0
#define ROW1 0x40
#define ROW2 0x14
#define ROW3 0x54
// commands
#define LCD_CLEARDISPLAY 0x01
#define LCD_RETURNHOME 0x02
#define LCD_ENTRYMODESET 0x04
#define LCD_DISPLAYCONTROL 0x08
#define LCD_CURSORSHIFT 0x10
#define LCD_FUNCTIONSET 0x20
#define LCD_SETCGRAMADDR 0x40
#define LCD_SETDDRAMADDR 0x80
// flags for display entry mode
#define LCD_ENTRYRIGHT 0x00
#define LCD_ENTRYLEFT 0x02
#define LCD_ENTRYSHIFTINCREMENT 0x01
#define LCD_ENTRYSHIFTDECREMENT 0x00
// flags for display on/off control
#define LCD_DISPLAYON 0x04
#define LCD_DISPLAYOFF 0x00
#define LCD_CURSORON 0x02
#define LCD_CURSOROFF 0x00
#define LCD_BLINKON 0x01
#define LCD_BLINKOFF 0x00
// flags for display/cursor shift
#define LCD_DISPLAYMOVE 0x08
#define LCD_CURSORMOVE 0x00
#define LCD_MOVERIGHT 0x04
#define LCD_MOVELEFT 0x00
// flags for function set
#define LCD_8BITMODE 0x10
#define LCD_4BITMODE 0x00
#define LCD_2LINE 0x08
#define LCD_1LINE 0x00
#define LCD_5x10DOTS 0x04
#define LCD_5x8DOTS 0x00
class LCD : public Print {
public:
LCD(uint8_t rs, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
LCD(uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
LCD(uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3);
LCD(uint8_t rs, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3);
void init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
void begin(uint8_t cols, uint8_t rows, uint8_t charsize = LCD_5x8DOTS);
void printf(const char * format, ... );
void printf_noscroll(const char * format, ... );
void CharOut(const char);
void CharOut_noscroll(const char c);
void clear();
void home();
void noDisplay();
void display();
void noBlink();
void blink();
void noCursor();
void cursor();
void scrollDisplayLeft();
void scrollDisplayRight();
void leftToRight();
void rightToLeft();
void autoscroll();
void noAutoscroll();
void createChar(uint8_t, uint8_t[]);
void setCursor(uint8_t, uint8_t);
void getCursor(uint8_t& col,uint8_t& row);
void setChar(uint8_t,char);
char getChar(uint8_t);
char getChar(uint8_t col, uint8_t row);
void ScrollUp();
virtual size_t write(uint8_t);
void command(uint8_t);
uint8_t GetBFlagAndCounter(void);
using Print::write;
private:
static const int row_offsets[4];
uint8_t read4bits(void);
void send(uint8_t, uint8_t);
void write4bits(uint8_t);
void write8bits(uint8_t);
void pulseEnable();
void pulseON();
uint8_t _rs_pin; // LOW: command. HIGH: character.
uint8_t _rw_pin; // LOW: write to LCD. HIGH: read from LCD.
uint8_t _enable_pin; // activated by a HIGH pulse.
uint8_t _data_pins[8];
uint8_t _displayfunction;
uint8_t _displaycontrol;
uint8_t _displaymode;
uint8_t _initialized;
uint8_t _numlines,_currline;
};
#endif
В моем классе LCD дополнительно доступны методы.
1. void printf(const char * format, ... ) - обычный printf.
2. void printf_noscroll(const char * format, ... ) - printf без прокрутки экрана вврех.
3. void CharOut(const char) - вывод символа в текущую позицию курсора.
4. void CharOut_noscroll(const char c) - вывод символа в текущую позицию курсора без прокрутки изображения, если кончиться экран.
5. void getCursor(uint8_t& col,uint8_t& row) - получение позиции курсора.
6. void setChar(uint8_t addr,char c) - запись символа "c" в адрес видеобуфера "addr".
7. char getChar(uint8_t addr) - получение содержимого ячейки видеобуфера addr.
8. char LCD::getChar(uint8_t col, uint8_t row) - получение символа в колонке col и строке row.
9. void ScrollUp() - прокрутка экрана вверх.
