Oliver Broad
Demo of LCD modified to use interrupts not delays.
Fork of
LCD_nonblocking_demo
by 
Oliver Broad
This is an experiment in controlling an LCD from callbacks independently of the main program loop. As it runs from callbacks it is necessary to check if the library is "busy", which is currently indicated by an integer called "busy".
Busy checking should be converted into a method so that the criteria for being "busy" can be changed without changing the API.
As this is rough I have not issued it as a library ... yet.
Also due to my inexperience using the repository manager this is currently listed as a fork of itself. Sorry.
Diff: main.cpp
- Revision:
- 3:f18aa98bc9a8
- Parent:
- 2:d87266912897
--- a/main.cpp Wed Nov 20 11:07:09 2013 +0000
+++ b/main.cpp Wed Nov 20 12:52:19 2013 +0000
@@ -13,445 +13,13 @@
*
*/
-#include "mbed.h"
-/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
- * Copyright (c) 2013, oliverb, http://mbed.org
- * Copyright (c) 2007-2010, sford, http://mbed.org
- *
- * 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.
- */
-
-#ifndef MBED_TEXTLCD_H
-#define MBED_TEXTLCD_H
-
-//#include "mbed.h"
-
-/** A TextLCD interface for driving 4-bit HD44780-based LCDs
- *
- * Currently supports 16x2, 20x2 and 20x4 panels
- *
- * Implements a "Busy" flag to indicate when display is unavailable
- * Busy is currently set by a timer and not by polling actual module
- *
- *
- * @code
- * #include "mbed.h"
- * #include "TextLCD.h"
- *
- * TextLCD lcd(p10, p12, p15, p16, p29, p30); // rs, e, d4-d7
- *
- * int main() {
- * lcd.printf("Hello World!\n");
- * }
- * @endcode
- */
-class TextLCD : public Stream
-{
-public:
-
- /** LCD panel format */
- enum LCDType {
- LCD16x2 /**< 16x2 LCD panel (default) */
- , LCD16x2B /**< 16x2 LCD panel alternate addressing */
- , LCD20x2 /**< 20x2 LCD panel */
- , LCD20x4 /**< 20x4 LCD panel */
- };
-
- /** Create a TextLCD interface
- *
- * @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)
- */
- TextLCD(PinName rs, PinName e, PinName d4, PinName d5, PinName d6, PinName d7, LCDType type = LCD16x2);
-
- void init();
-
-
-#if DOXYGEN_ONLY
- /** Write a character to the LCD
- *
- * @param c The character to write to the display
- */
- int putc(int c);
-
- /** Write a formated string to the LCD
- *
- * @param format A printf-style format string, followed by the
- * variables to use in formating the string.
- */
- volatile int printf(const char* format, ...);
-#endif
-
- /** Locate to a screen column and row
- *
- * @param column The horizontal position from the left, indexed from 0
- * @param row The vertical position from the top, indexed from 0
- */
- void locate(int column, int row);
-
- /** Clear the screen and locate to 0,0 */
- void cls();
-
- int rows();
- int columns();
-
- volatile int busy;
-
-protected:
- Timeout timer;
-
-// callbacks used by "init" to carry out steps of initialisation
- void init2();
- void init2b();
-
- void init3();
- void init4();
- void init5();
- void init6();
- void init7();
- void init8();
-// void init9();
- // Stream implementation functions
- virtual int _putc(int value);
- virtual int _getc();
-
- int address(int column, int row);
-// void character(int column, int row, int c);
- void writeByte(int value);
- void writeCommand(int command);
- void writeData(int data);
- void callback();
- void locate_cb();
-
- DigitalOut _rs, _e;
- BusOut _d;
- LCDType _type;
-
- int _column;
- int _row;
- char _queue[40];
- volatile int _head;
- volatile int _tail;
-// int _loop;
-};
-
-#endif
-/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
- * Copyright (c) 2007-2010, sford, http://mbed.org
- *
- * 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"
-
-
+#include "LCD_nonblocking.h"
DigitalOut Led1(LED1);
DigitalOut Led2(LED2);
DigitalOut Led3(LED3);
DigitalOut Led4(LED4);
-
-
-
-TextLCD::TextLCD(PinName rs, PinName e, PinName d4, PinName d5,
- PinName d6, PinName d7, LCDType type) : busy(0),_rs(rs),
- _e(e), _d(d4, d5, d6, d7),
- _type(type) , _column(0),_row(0),
- _head(0), _tail(0) {}
-void TextLCD::init()
-{
-
- busy=1;
- _rs = 1;
- _d = 0;
- wait_us(1);
- _e = 0;
- _rs = 0; // command mode
- timer.attach_us(this,&TextLCD::init2,15000);
-}
-void TextLCD::init2()
-{
- _rs = 0;
- _d = 0x3;
- _e = 1;
- wait_us(1);
- _e = 0;
- timer.attach_us(this,&TextLCD::init2b,4100);
-}
-void TextLCD::init2b()
-{
-
- _d = 0x3;
- _e = 1;
- wait_us(1);
- _e = 0;
- timer.attach_us(this,&TextLCD::init3,4100);
-}
-void TextLCD::init3()
-{
- _d = 0x3;
- _e = 1;
- wait_us(1);
- _e = 0;
- timer.attach_us(this,&TextLCD::init4,1000);
-}
-void TextLCD::init4()
-{
- _d = 0x2;
- _e = 1;
- wait_us(1);
- _e = 0;
- timer.attach_us(this,&TextLCD::init5,60);
-}
-void TextLCD::init5()
-{
-
- writeByte(0x28); // Function set 001 BW N F - -
- timer.attach_us(this,&TextLCD::init6,60);
-}
-void TextLCD::init6()
-{
- writeByte(0x0C);
- timer.attach_us(this,&TextLCD::init7,60);
-}
-void TextLCD::init7()
-{
- writeByte(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
- timer.attach_us(this,&TextLCD::init8,60);
-}
-void TextLCD::init8()
-{
- writeByte(0x01); // cls, and set cursor to 0
- // This command takes 1.64 ms
- locate(0, 0);
- timer.attach_us(this,&TextLCD::locate_cb,1640);
-}
-/*
-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;
-}
-/* this is the general buffered-write callback for writing text to the display
- * it normally chains to itself unless a newline occurs in which case it chains to
- * locate_cb
- * or the buffer runs out in which case it clears busy and does not chain
- */
-
-void TextLCD::callback()
-{
- if (_tail<_head) {
- int value=_queue[_tail++];
- if (value == '\n') {
- _column = 0;
- _row++;
- if (_row >= rows()) {
- _row = 0;
- }
- locate_cb(); // newline isn't printed so go straight to "locate" code
- } else {
- _rs = 1; // data mode
- writeByte(value);
- _column++;
- if (_column >= columns()) { //if we've reached the end of line then chain to "locate"
- //otherwise go back to callback
- _column = 0;
- _row++;
- if (_row >= rows()) {
- _row = 0;
- }
- timer.attach_us(this,&TextLCD::locate_cb,60);
- } else {
- timer.attach_us(this,&TextLCD::callback,60);
- }
-
- }
-
- } else { //if we've run out of text then clear flag
- _head=_tail=0;
- busy=0;
- }
-}
-
-void TextLCD::locate_cb()
-{
- int a = address(_column, _row);
- _rs=0;
- writeByte(a);
- timer.attach_us(this,&TextLCD::callback,60);
-}
-
-
-int TextLCD::_putc(int value)
-{
- if (_head<40) {
- _queue[_head++]=value;
- };
- if (busy==0) {
- busy=1;
- locate_cb(); // set cursor position before text
- /*
- int a = address(_column, _row);
- _rs=0;
- writeByte(a);
- timer.attach_us(this,&TextLCD::callback,60);
- */
- };
- return 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::writeByte(int value)
-{
- _d = value >> 4;
- _e = 1;
- wait_us(1);
- _e = 0;
- _d = value >> 0;
- wait_us(2);
- _e = 1;
- wait_us(1); // most instructions take 40us
- _e = 0;
-}
-
-void TextLCD::writeCommand(int command)
-{
- _rs = 0; //command mode
- wait_us(50); // most instructions take 40us
- writeByte(command);
-}
-
-void TextLCD::writeData(int data)
-{
- _rs = 1; // data mode
- wait_us(50); // most instructions take 40us
- writeByte(data);
-}
-
-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;
- }
-}
-
TextLCD lcd(p15, p16, p17, p18, p19, p20, TextLCD::LCD20x4); // rs, e, d4-d7