Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/visrealm/vremulcd
Character LCD emulator library (C99 engine, web front-end).
https://github.com/visrealm/vremulcd
1602-lcd 1602lcd arduino c character-lcd emscripten emulator hd44780 javascript lcd lcd-display lcd-screen wasm webassembly
Last synced: 5 days ago
JSON representation
Character LCD emulator library (C99 engine, web front-end).
- Host: GitHub
- URL: https://github.com/visrealm/vremulcd
- Owner: visrealm
- License: mit
- Created: 2020-03-19T06:34:22.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2024-07-04T13:49:16.000Z (6 months ago)
- Last Synced: 2024-11-25T10:50:33.753Z (27 days ago)
- Topics: 1602-lcd, 1602lcd, arduino, c, character-lcd, emscripten, emulator, hd44780, javascript, lcd, lcd-display, lcd-screen, wasm, webassembly
- Language: C
- Homepage: https://cpu.visualrealmsoftware.com/emu/?h=7e387e0f377e010716bd0c7d1042303915fcc22f0d6e48656c6c6f2c20576f726c642100
- Size: 3.62 MB
- Stars: 64
- Watchers: 3
- Forks: 12
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# vrEmuLcd - HD44780 Character LCD Emulator
Core engine written in C with a flexible Web front-end.
This Character LCD Emulator can be used to emulate most standard LCD displays.
It accepts and responds to most commands listed in the [HD44780 datasheet](https://www.sparkfun.com/datasheets/LCD/HD44780.pdf)
It also now support most commands for a 128x64 graphics LCD [12864B datasheet](https://www.exploreembedded.com/wiki/images/7/77/QC12864B.pdf)
## Screenshots:
#### Hello, World!
#### Different Colors
#### Different Sizes
#### 128 x 64 Graphics LCD
#### Custom characters (CGRAM support)
## Live examples:
* [Hello, World!](https://visrealm.github.io/vrEmuLcd/examples/helloworld)
* [The 8-Bit Guy: Character LCD](https://visrealm.github.io/vrEmuLcd/examples/8bitguy)
* [Hello Graphics LCD](https://visrealm.github.io/vrEmuLcd/examples/hellogfx)
* [Troy's Breadboard Computer!](https://cpu.visualrealmsoftware.com/emu/?h=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&s=300)
## Usage
### C
```c
#define LCD_WIDTH 20
#define LCD_HEIGHT 4
VrEmuLcd *lcd = vrEmuLcdNew(LCD_WIDTH, LCD_HEIGHT, EmuLcdRomA00);
// send it commands:
vrEmuLcdSendCommand(lcd, LCD_CMD_FUNCTION | LCD_CMD_FUNCTION_LCD_2LINE | 0x10);
vrEmuLcdSendCommand(lcd, LCD_CMD_CLEAR);
vrEmuLcdSendCommand(lcd, LCD_CMD_HOME);
vrEmuLcdSendCommand(lcd, LCD_CMD_DISPLAY | LCD_CMD_DISPLAY_ON);
// send it data
vrEmuLcdWriteByte(lcd, 'H');
vrEmuLcdWriteByte(lcd, 'e');
vrEmuLcdWriteByte(lcd, 'l');
vrEmuLcdWriteByte(lcd, 'l');
vrEmuLcdWriteByte(lcd, 'o');
// or cheat
vrEmuLcdWriteString(lcd, " world!");
// then periodically, render it.
vrEmuLcdUpdatePixels(lcd); // generates a snapshot of the pixels state
for (int y = 0; y < vrEmuLcdNumPixelsY(lcd); ++y) {
for (int x = 0; x < vrEmuLcdNumPixelsX(lcd); ++x) {
// do whatever you like with the pixel information. render it to a texture, output it to a console, whatever
// values returned are: -1 = no pixel (character borders), 0 = pixel off, 1 = pixel on
char pixel = vrEmuLcdPixelState(lcd, x, y);
}
}
```
### Web
#### HTML (local)
```html
```
#### HTML (live)
```html
```
## Example
```js
...
var canv = document.getElementById('lcd');
var ctx = canv.getContext('2d');
vrEmuLcd.setLoadedCallback(function () {
// create a new LCD object
var lcd = vrEmuLcd.newLCD(16, 2, vrEmuLcd.CharacterRom.Eurpoean);
// set up the display
lcd.sendCommand(LCD_CMD_DISPLAY | LCD_CMD_DISPLAY_ON);
lcd.writeString("Hello, World!");
lcd.render(ctx, 0, 0, 800, 400);
});
```
## LCD API
#### constuctor
```js
var lcd = vrEmuLcd.newLCD(columns, rows, charSet);
```
- `columns`: - number of columns
- `rows`: - number of rows
- `charSet`: - character set. One of: `vrEmuLcd.CharacterRom.European`, `vrEmuLcd.CharacterRom.Japanese`
#### sendCommand(commandByte)
Send a command to the instruction register of the lcd
Command constants are defined:
- `LCD_CMD_CLEAR` - clear the display
- `LCD_CMD_HOME` - reset display to home position
- `LCD_CMD_ENTRY_MODE` - entry mode (the following to be bitwise-OR'd)
- `LCD_CMD_ENTRY_MODE_INCREMENT` - automatically increment the cursor or display
- `LCD_CMD_ENTRY_MODE_DECREMENT` - automatically decrement the cursor or display
- `LCD_CMD_ENTRY_MODE_SHIFT` - automaticallt shift the entire display instead of the cursor
- `LCD_CMD_DISPLAY` - display mode (the following to be bitwise-OR'd)
- `LCD_CMD_DISPLAY_ON` - turn the display on
- `LCD_CMD_DISPLAY_CURSOR` - display a cursor (bottom row)
- `LCD_CMD_DISPLAY_CURSOR_BLINK` - display a blink cursor (flashing entire character block)
- `LCD_CMD_SHIFT` - move the cursor or scroll display (the following to be bitwise-OR'd)
- `LCD_CMD_SHIFT_CURSOR` - shift the cursor (default)
- `LCD_CMD_SHIFT_DISPLAY` - shift the display
- `LCD_CMD_SHIFT_LEFT` - shift the cursor or display left (default)
- `LCD_CMD_SHIFT_RIGHT` - shift the cursor or display right
- `LCD_CMD_SET_CGRAM_ADDR` - set the CGRAM address (actual address uses lower 6 bits)
- `LCD_CMD_SET_DRAM_ADDR` - set the CGRAM address (actual address uses lower 7 bits)
#### writeByte(dataByte)
Write a byte to the data register of the lcd
#### writeString(str)
Write a string to the data register of the lcd
#### getDataOffset(screenX, screenY)
Return the ddram offset for the given screen location
#### readByte()
Read the current byte from cgram or ddram (determined by current address)
#### readAddress()
Read the current address offset in cgram or ddram
#### pixelState(pixelX, pixelY)
Return the pixel state at the given location
- `-1` - no pixel (eg. margin)
- `0` - pixel off
- `1` - pixel on
#### colorScheme
Set/get the color scheme. eg:
```js
lcd.colorScheme = vrEmuLcd.Schemes.WhiteOnBlue;
```
Standard color schemes:
- `vrEmuLcd.Schemes.WhiteOnBlue` (default)
- `vrEmuLcd.Schemes.BlackOnBlue`
- `vrEmuLcd.Schemes.BlackOnGreen`
- `vrEmuLcd.Schemes.RedOnBlack`
- `vrEmuLcd.Schemes.BlueOnBlack`
or, provide your own. `{ BackColor: , PixelOnColor: , PixelOffColor: }`
#### render(ctx, x, y, width, height)
Render to a 2d canvas context
- `ctx` - the canvas to render to
## License
This code is licensed under the [MIT](https://opensource.org/licenses/MIT "MIT") license