LCD-Custom-Char-Maker

Create Custom Characters for LCD displays connected to Arduino, Raspberry Pi, Tinkerforge or other

• Created with B4J v8.00 - development tool for cross platform desktop, server and IoT solutions.
• Requires Java JDK 8 to run. Ensure to comply to the Oracle JDK Licence agreement.
• Developed for personal & development use only.

Functionality

• Create custom LCD character with 5 pixel horizontal (cols), 8 pixel vertical (rows).
• Each row is represented by a byte with 5 bits.
• Create DEC, HEX and BIN arrays.
• Save / open the character to / from a textfile located in the application folder.
• Import 8 bytes array string in format 0xNN,0xNN... where NN is HEX value.
• Convert LCD character table high & low bits to DEC & HEX values.
• Various language specific examples
• Some example chars in the project source/objects folder.

Files

• lcdcustomcharmaker.zip contains the application, sample characters and examples.

Install

From the source/Objects folder, run the Java jar lcdcustomcharmaker.jar

java -jar lcdcustomcharmaker.jar

Notes:

• The full B4J source code is included (folder source).
• An example batch file "run8.bat" to run under Windows is included. Ensure to set the path to the JDK8 folder.
• There is also a "run11.bat" for running with openJDK11 - might require to recompile first with B4J using openJDK11.

Example Coding Custom Character Battery

This example covers various development tools B4R, B4J and dedicated Tinkerforge 20x4 bricklet with C, Java, JavaScript, MQTT & Python.

Example output for the custom character Battery (empty):

' B4X HEX array
Dim battery(8) As Byte
battery = Array As Byte (0x0E, 0x1B, 0x11, 0x11, 0x11, 0x11, 0x11, 0x1F)

// C byte array
Byte battery[8] = {B01110, B11011, B10001, B10001, B10001, B10001, B10001, B11111};
// C int8_t array
int8_t battery[8] = {14, 27, 17, 17, 17, 17, 17, 31};

# Python int array
battery = [14, 27, 17, 17, 17, 17, 17, 31]

// Java short array
short[] battery = new short[]{14, 27, 17, 17, 17, 17, 17, 31}

// JavaScript int array
battery = [14, 27, 17, 17, 17, 17, 17, 31]

# JSON Tinkerforge MQTT2 index 0 and int array
{"index":0, "character":[14, 27, 17, 17, 17, 17, 17, 31]}

Tinkerforge

The LCD 20x4 Bricklet supports up to 8 custom characters 0-7 which are mapped to \u0008-\u000F (\u takes hex numbers). Tested defining and writing custom characters with an LCD 20x4 v1.2 Bricklet having UID=BHN. Some API snippet exmples.

C

// Create device object
LCD20x4 lcd;

// Clear display & turn backlight on
lcd_20x4_clear_display(&lcd);
lcd_20x4_backlight_on(&lcd);

// Custom Char battery assigned to index 0 (from max 7)
int8_t battery[8] = {14,27,17,17,17,17,17,31};
lcd_20x4_set_custom_character(&lcd,0, battery);
// Write text and the custom character
lcd_20x4_write_line(&lcd, 0, 0, "Battery: \x08"); 

Java

BrickletLCD20x4 lcd = new BrickletLCD20x4(UID, ipcon); // Create device object

// Clear & turn backlight on
lcd.clearDisplay();
lcd.backlightOn();

// Custom Char battery assigned to index 0 (from max 7)
short[] battery = new short[]{14,27,17,17,17,17,17,31};
lcd.setCustomCharacter((short)0, battery);
// Display the custom char with some text
lcd.writeLine((short)0, (short)0, "Battery: " + "\u0008");
//lcd.writeLine((short)0, (short)0, "Battery: " + (char)0x08); 

JavaScript

var lcd = new Tinkerforge.BrickletLCD20x4(UID, ipcon); // Create device object

// Clear & turn backlight on
lcd.clearDisplay();
lcd.backlightOn();

// Custom Char battery assigned to index 0 (from max 7)
battery = [14,27,17,17,17,17,17,31]
lcd.setCustomCharacter(0, battery)
// Display the custom char with some text
lcd.writeLine(0, 0, "Battery: " + "\x08")        

MQTT V2

Test 1: Turn the display backlight on, clear the display and display text string "Hello World".

mosquitto_pub -t tinkerforge/request/lcd_20x4_bricklet/BHN/backlight_on -m ''
mosquitto_pub -t tinkerforge/request/lcd_20x4_bricklet/BHN/clear_display -m ''
mosquitto_pub -t tinkerforge/request/lcd_20x4_bricklet/BHN/write_line -m '{"line": 0, "position": 0, "text": "Hello World"}'

Test 2: Define & custom character Battery.

The JSON definition for the custom character battery set to index 0 (the first custom character at position 0x08 = \u0008):

{"index":0, "character":[14, 27, 17, 17, 17, 17, 17, 31]}

Set custom character 0:

mosquitto_pub -t tinkerforge/request/lcd_20x4_bricklet/BHN/set_custom_character -m '{"index":0, "character":[14, 27, 17, 17, 17, 17, 17, 31]}'

Write it to the display with some text:

mosquitto_pub -t tinkerforge/request/lcd_20x4_bricklet/BHN/write_line -m '{"line": 0, "position": 0, "text": "Battery: \u0008"}'

Python

lcd = BrickletLCD20x4(UID, ipcon) # Create device object

# Clear & Turn backlight on
lcd.clear_display()
lcd.backlight_on()

# Custom Char battery assigned to index 0 (from max 7)
battery = [14,27,17,17,17,17,17,31]
lcd.set_custom_character(0, battery)
# Display the custom char with some text
lcd.write_line(0, 0, "Battery: " + "\x08")

B4R

B4R Binary Definition

Byte battery[8] = {B01110,B11011,B10001,B10001,B10001,B10001,B10001,B11111};                            

B4R Example

InlineC Code is required to display the special characters. This example can be used by copy and paste in projects.

'Inline C to define the special characters
'Usage:
'  Private CharArrowUp As Byte = 0
'  Private CharArrowDown As Byte = 1
'  Private CharArrowEq As Byte = 2
'  RunNative("createChar", Null)
'  lcd.SetCursor(0,0)
'  RunNative("writeChar", CharArrowUp)                
'  lcd.SetCursor(5,0)
'  RunNative("writeChar", CharArrowDown)
'  lcd.SetCursor(10,0)
'  RunNative("writeChar", CharArrowEq)
#if C                                                               
Byte arrowup[8] = {B00000,B00100,B01110,B11111,B00100,B00100,B00100,B00000};
Byte arrowdown[8] = {B00000,B00100,B00100,B00100,B11111,B01110,B00100,B00000};
Byte arroweq[8] = {B00000,B00000,B11111,B00000,B11111,B00000,B00000,B00000};

//Create the special chars:0=arrow up, 1=arrow down, 2=arrow equal
//RunNative("createChar", Null)
void createChar(B4R::Object* o) {
   b4r_main::_lcd->lc->createChar(0, arrowup);
   b4r_main::_lcd->lc->createChar(1, arrowdown);
   b4r_main::_lcd->lc->createChar(2, arroweq);
}

//Write a special character to the display: 0=arrow up, 1=arrow down, 2=arrow equal
//lcd.SetCursor(0,1)
//RunNative("writeChar", 0)
void writeChar(B4R::Object* o) {
   b4r_main::_lcd->lc->write((Byte)o->toULong());
}
#end if                                                          

Hint

To write a character from the character table of the LCD Display driver. The Degree Character ° is located at position upper 4 bits 1101 and lower 4 bits 1111. The 8 bits 1101 1111 are HEX DF and DEC 223. To write the character to the LCD use lcd.Write(Array As Byte(223)).

LCD Character Table

Convert Upper 4 & Lower 4 bits to HEX and Unicode Example Cent Character: Upper 4 bits = 1110, Lower 4 bits = 1111 Converted: 11101111 = EF , 0xEF , \u00EF, 239

Use the LCD display datasheet accordingly.

Licence

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS for A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with the samples. If not, see GNU Licenses.