PIC32MX: Parallel LCD - Revision history

NickMarchuk at 19:27, 11 January 2010

2010-01-11T19:27:45Z

NickMarchuk: /* Files and Example Code */

2010-01-11T19:24:20Z

Files and Example Code

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NickMarchuk: /* Files and Example Code */

2010-01-11T19:04:44Z

Files and Example Code

NickMarchuk: /* Files and Example Code */

2010-01-11T19:03:34Z

Files and Example Code

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NickMarchuk at 19:00, 11 January 2010

2010-01-11T19:00:56Z

NickMarchuk at 18:46, 11 January 2010

2010-01-11T18:46:16Z

NickMarchuk at 18:41, 11 January 2010

2010-01-11T18:41:14Z

NickMarchuk at 02:22, 5 January 2010

2010-01-05T02:22:38Z

NickMarchuk at 02:20, 5 January 2010

2010-01-05T02:20:28Z

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NickMarchuk at 02:54, 4 January 2010

2010-01-04T02:54:00Z

@@ Line 97: / Line 97: @@
 </pre></code>
-Write the contents of an integer using
+Write the contents of a variable using
 <code><pre>
+char buffer[5]; // this will store the string
-// write the value of int counter
+int n; // this is the number of characters in the string after it has been converted
-putsLCD("\fCounter = %f", counter); //currently not supported NDM 1/4/10
+short a = 10; // the number we will convert to a string
+n=sprintf(buffer, "%d", a); // make the string and see how many characters there are
+putsLCD("a = "); // write some text
+putsLCD(buffer);  // write the contents of the variable
 </pre></code>

@@ Line 105: / Line 105: @@
 == Files and Example Code ==
-Include the following h and c files to your project:
+Include the following h and c files to your project: [[Media:LCD_NU32.zip|h and c files]]
 '''LCD.h'''

@@ Line 1: / Line 1: @@
-The popular HD44780 (and compatible chipsets) can be interfaced to the NU32 PIC32 board using 6 pins for easy character output to an LCD. This can be highly useful in either debugging or generating a more complex user interface for a PIC (or other microcontroller)-based device.
+== Parallel LCD ==
+The popular HD44780 (and compatible chipsets) can be interfaced to the NU32 PIC32 board using 6 pins for easy character output to an LCD. This can be highly useful in either debugging or generating a more complex user interface for a PIC (or other microcontroller)-based device.
+This implementation of an HD44780 LCD uses only 6 I/O on the PIC, but is not optimized for speed. If you need more efficient output, more pins can be used for communication, and this code would need to be altered slightly, but for debugging purposes start with this implementation.
+== LCD Hookup ==
 First you will need to locate the appropriate datasheet for the actual LCD you are using. What you will want to look up in there is the arrangement of connectors on the top-left of the display, and their names so that you can appropriately match the right connectors with the correct pins on the microcontroller, and in turn with the correct software identifiers for those connections. An example of one such pin arrangement is below.
@@ Line 61: / Line 68: @@
 The NU32 board is based on 3.3V logical outputs, which works fine for most LCDs.
+== LCD Commands ==
 In the main.c file, before the main while loop, you must initialize the LCD
@@ Line 94: / Line 103: @@
 putsLCD("\fCounter = %f", counter); //currently not supported NDM 1/4/10
 </pre></code>
+== Files and Example Code ==
 Include the following h and c files to standardize the communication:

@@ Line 1: / Line 1: @@
-Using 7 pins on the PIC32 it is possible to interface with the popular HD44780 (and compatible chipsets) for easy character output to an LCD.  This can be highly useful in either debugging or generating a more complex user interface for a PIC (or other microcontroller)-based device.
+The popular HD44780 (and compatible chipsets) can be interfaced to the NU32 PIC32 board using 6 pins for easy character output to an LCD. This can be highly useful in either debugging or generating a more complex user interface for a PIC (or other microcontroller)-based device.
-First you will need to locate the appropriate datasheet for the actual LCD you are using.  What you will want to look up in there is the arrangement of connectors on the top-left of the display, and their names so that you can appropriately match the right connectors with the correct pins on the microcontroller, and in turn with the correct software identifiers for those connections.  An example of one such pin arrangement is below.
+First you will need to locate the appropriate datasheet for the actual LCD you are using. What you will want to look up in there is the arrangement of connectors on the top-left of the display, and their names so that you can appropriately match the right connectors with the correct pins on the microcontroller, and in turn with the correct software identifiers for those connections. An example of one such pin arrangement is below.
 <table>
@@ Line 32: / Line 32: @@
 </table>
-Your controller may differ from this one.  Occasionally even if you've got the right datasheet these pin numbers can be backwards.  If it has a backlight, try powering that up first and ensure that works.
+Your controller may differ from this one. Occasionally even if you've got the right datasheet these pin numbers can be backwards. If it has a backlight, try powering that up first and ensure that works.
 Next, you'll need to wire up the LCD for power, and the connections with the pic.
@@ Line 56: / Line 56: @@
 </table>
-The VEE pin on the LCD sets the contrast of the characters on the LCD. Play with a voltage around 1V to get a nice contrast, or hook it to GND through a 1.5kOhm resistor, which also seems to work well.
+The VEE pin on the LCD sets the contrast of the characters on the LCD. Create with a voltage around 1V using a 10k pot to get a nice contrast, or hook it to GND through a 1.5kOhm resistor, which also seems to work well.
-If you power the LCD but do not send it any commands, the top row should fill with boxes. Use this to check that your LCD works.
+If you power the LCD but do not send it any commands, the top row should fill with boxes. Use this to set your contrast and check that your LCD works.
 The NU32 board is based on 3.3V logical outputs, which works fine for most LCDs.
-In your main.c file, before your main while loop, you must initialize the LCD
+In the main.c file, before the main while loop, you must initialize the LCD
 <code><pre>
 lcd_init();  // Always call this first

@@ Line 40: / Line 40: @@
 <tr><td>1 - VSS</td><td>GND</td></tr>
 <tr><td>2 - VCC</td><td>+5V</td></tr>
-<tr><td>3 - VEE</td><td>1.5kOhm to GND</td></tr>
+<tr><td>3 - VEE</td><td>~1V</td></tr>
 <tr><td>4 - RS</td><td>D4</td></tr>
-<tr><td>5 - R/W</td><td>D9</td></tr>
+<tr><td>5 - R/W</td><td>GND</td></tr>
 <tr><td>6 - E</td><td>D10</td></tr>
 <tr><td>7 - DB0</td><td>NC</td></tr>
@@ Line 60: / Line 60: @@
 If you power the LCD but do not send it any commands, the top row should fill with boxes. Use this to check that your LCD works.
-The NU32 board is based on 3.3V logical outputs, but some LCDs require 5V, so put the PIC output pins in open drain mode and use pull up resistors to +5V to enable the PIC to output 5V.
+The NU32 board is based on 3.3V logical outputs, which works fine for most LCDs.
-<code><pre>
-//Set D0-4,D9-10 as a digital output, open drain
-LATD |= 0x061F; TRISD &= 0xF9E0;
-mPORTDOpenDrainOpen(BIT_0 | BIT_1 | BIT_2 | BIT_3 | BIT_4 | BIT_9 | BIT_10);
-</pre></code>
 In your main.c file, before your main while loop, you must initialize the LCD

@@ Line 355: / Line 355: @@
 }
 #endif
@@ Line 421: / Line 420: @@
 </pre></code>
+To test these commands, here is a basic main file that writes some text:
 main.c
 <code><pre>
@@ Line 426: / Line 426: @@
 #include "HardwareProfile.h"
 #include <plib.h>
-//#include "LCD.h"
 #define SYS_FREQ	80000000L