Revision 0:42626fc1bbc5, committed 2009-11-30

Comitter:

simon

Date:

Mon Nov 30 09:32:28 2009 +0000

Commit message:

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TextDisplay.cpp	Mon Nov 30 09:32:28 2009 +0000
@@ -0,0 +1,57 @@
+/* mbed TextDisplay Display Library Base Class
+ * Copyright (c) 2007-2009 sford
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+ 
+#include "TextDisplay.h"
+
+TextDisplay::TextDisplay(const char *name) : Stream(name) {
+    _row = 0;
+    _column = 0;
+}
+    
+int TextDisplay::_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;
+}
+
+// crude cls implementation, should generally be overwritten in derived class
+void TextDisplay::cls() {
+    locate(0, 0);
+    for(int i=0; i<columns()*rows(); i++) {
+        putc(' ');
+    }
+}
+
+void TextDisplay::locate(int column, int row) {
+    _column = column;
+    _row = row;
+}
+
+int TextDisplay::_getc() {
+    return -1;
+}
+        
+void TextDisplay::foreground(int colour) {
+    _foreground = colour;
+}
+
+void TextDisplay::background(int colour) {
+    _background = colour;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TextDisplay.h	Mon Nov 30 09:32:28 2009 +0000
@@ -0,0 +1,52 @@
+/* mbed TextDisplay Library Base Class
+ * Copyright (c) 2007-2009 sford
+ * Released under the MIT License: http://mbed.org/license/mit
+ *
+ * A common base class for Text displays
+ * To port a new display, derive from this class and implement
+ * the constructor (setup the display), character (put a character
+ * at a location), rows and columns (number of rows/cols) functions.
+ * Everything else (locate, printf, putc, cls) will come for free
+ *
+ * The model is the display will wrap at the right and bottom, so you can
+ * keep writing and will always get valid characters. The location is 
+ * maintained internally to the class to make this easy
+ */
+
+#ifndef MBED_TEXTDISPLAY_H
+#define MBED_TEXTDISPLAY_H
+
+#include "mbed.h"
+
+class TextDisplay : public Stream {
+public:
+
+    // functions needing implementation in derived implementation class
+    TextDisplay(const char *name = NULL);
+    virtual void character(int column, int row, int c) = 0;
+    virtual int rows() = 0;
+    virtual int columns() = 0;
+    
+    // functions that come for free, but can be overwritten
+    virtual void cls();
+    virtual void locate(int column, int row);
+    virtual void foreground(int colour);
+    virtual void background(int colour);
+    // putc (from Stream)
+    // printf (from Stream)
+    
+protected:
+
+    virtual int _putc(int value);
+    virtual int _getc();
+
+    // character location
+    short _column;
+    short _row;
+
+    // colours
+    int _foreground;
+    int _background;
+};
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TextLCD.cpp	Mon Nov 30 09:32:28 2009 +0000
@@ -0,0 +1,98 @@
+/* mbed TextLCD Library
+ * Copyright (c) 2007-2009 sford
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+ 
+#include "TextLCD.h"
+#include "mbed.h"
+
+/*
+ * useful info found at http://www.a-netz.de/lcd.en.php
+ *
+ * Initialisation
+ * ==============
+ *
+ * After attaching the supply voltage/after a reset, the display needs to be brought in to a defined state
+ *
+ * - wait approximately 15 ms so the display is ready to execute commands
+ * - Execute the command 0x30 ("Display Settings") three times (wait 1,64ms after each command, the busy flag cannot be queried now). 
+ * - The display is in 8 bit mode, so if you have only connected 4 data pins you should only transmit the higher nibble of each command.
+ * - If you want to use the 4 bit mode, now you can execute the command to switch over to this mode now.
+ * - Execute the "clear display" command
+ *
+ * Timing
+ * ======
+ *
+ * Nearly all commands transmitted to the display need 40us for execution. 
+ * Exceptions are the commands "Clear Display and Reset" and "Set Cursor to Start Position" 
+ * These commands need 1.64ms for execution. These timings are valid for all displays working with an 
+ * internal clock of 250kHz. But I do not know any displays that use other frequencies. Any time you 
+ * can use the busy flag to test if the display is ready to accept the next command.
+ * 
+ * _e is kept high apart from calling clock
+ * _rw is kept 0 (write) apart from actions that uyse it differently
+ * _rs is set by the data/command writes
+ */
+
+TextLCD::TextLCD(PinName rs, PinName rw, PinName e, PinName d0, PinName d1, 
+    PinName d2, PinName d3, const char *name) : TextDisplay(name), _rw(rw), _rs(rs), 
+    _e(e), _d(d0, d1, d2, d3) {
+
+    _rw = 0;
+    _e  = 1;
+    _rs = 0; // command mode
+
+    // Should theoretically wait 15ms, but most things will be powered up pre-reset
+    // so i'll disable that for the minute. If implemented, could wait 15ms post reset
+    // instead
+    // wait(0.015); 
+        
+    // 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
+    }
+    writeByte(0x2); // 4-bit mode
+            
+    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 address = 0x80 + (row * 40) + column; // memory starts at 0x80, and is 40 chars long per row
+      writeCommand(address);           
+      writeData(c); 
+}
+
+int TextLCD::columns() {
+    return 16;
+}
+
+int TextLCD::rows() { 
+    return 2; 
+}
+
+void TextLCD::writeByte(int value) {
+    _d = value >> 4;
+    wait(0.000040f); // most instructions take 40us
+    _e = 0;
+    wait(0.000040f);  
+    _e = 1;    
+    _d = value >> 0;
+    wait(0.000040f);
+    _e = 0;
+    wait(0.000040f);  // most instructions take 40us
+    _e = 1;    
+}
+
+void TextLCD::writeCommand(int command) {
+    _rs = 0;
+    writeByte(command);
+}
+
+void TextLCD::writeData(int data) {
+    _rs = 1;
+    writeByte(data);
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TextLCD.h	Mon Nov 30 09:32:28 2009 +0000
@@ -0,0 +1,30 @@
+/* mbed TextLCD Library Base Class
+ * Copyright (c) 2007-2009 sford
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+#include "TextDisplay.h"
+
+#ifndef MBED_TEXTLCD_H
+#define MBED_TEXTLCD_H
+
+class TextLCD : public TextDisplay {
+public:
+
+    TextLCD(PinName rs, PinName rw, PinName e, PinName d0, PinName d1, PinName d2, PinName d3, const char *name = NULL);
+    virtual void character(int column, int row, int c);
+    virtual int rows(); 
+    virtual int columns();  
+
+    // locate, cls, putc, printf come from derived class
+    
+protected:
+
+    void writeByte(int value);
+    void writeCommand(int command);
+    void writeData(int data);
+
+    DigitalOut _rw, _rs, _e;
+    BusOut _d;
+};
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Nov 30 09:32:28 2009 +0000
@@ -0,0 +1,32 @@
+// example showing how to re-route stdout, sford
+
+#include "mbed.h"
+#include "TextLCD.h"
+
+Serial pc(USBTX, USBRX, "hi");
+TextLCD lcd(p10, p11, p12, p15, p16, p29, p30, "lcd"); // rs, rw, e, d0-d3, name
+LocalFileSystem local("local");
+
+int main() {
+    // printf to specific peripherals
+    pc.printf("Hello World!\n");
+    lcd.printf("Hello World!\n");
+
+    // printf to stdout
+    printf("Hello USB Serial World!\n");
+    
+    // change stdout to file
+    freopen("/local/output.txt", "w", stdout);
+    printf("Hello FileSystem World!\n");
+    fclose(stdout);
+    
+    // change stdout to LCD
+    freopen("/lcd", "w", stdout);
+    printf("Hello LCD World!\n");
+    fclose(stdout);
+
+    wait(5);    
+
+    pc.printf("Hello World!\n");
+    lcd.printf("Hello World!\n");
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Nov 30 09:32:28 2009 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/32af5db564d4