mirror of
https://github.com/RobTillaart/Arduino.git
synced 2024-10-03 18:09:02 -04:00
272 lines
8.3 KiB
Markdown
272 lines
8.3 KiB
Markdown
|
|
[](https://github.com/marketplace/actions/arduino_ci)
|
|
[](https://github.com/RobTillaart/I2C_LCD/actions/workflows/arduino-lint.yml)
|
|
[](https://github.com/RobTillaart/I2C_LCD/actions/workflows/jsoncheck.yml)
|
|
[](https://github.com/RobTillaart/I2C_LCD/issues)
|
|
|
|
[](https://github.com/RobTillaart/I2C_LCD/blob/master/LICENSE)
|
|
[](https://github.com/RobTillaart/I2C_LCD/releases)
|
|
[](https://registry.platformio.org/libraries/robtillaart/I2C_LCD)
|
|
|
|
|
|
# I2C_LCD
|
|
|
|
Arduino library for I2C_LCD LCD displays.
|
|
|
|
|
|
**Warning: experimental with side effects, use at own risk**
|
|
|
|
do not overfeed your display with too much data
|
|
too fast as it may not be able to handle.
|
|
During longer tests my 20x4 display garbled too often.
|
|
Under investigation.
|
|
|
|
|
|
## Description
|
|
|
|
**Experimental** Arduino library for the I2C LCD display, typical 20x4 characters.
|
|
|
|
The library is inspired by the excellent LiquidCrystel_I2C library of F. Malpartida.
|
|
Therefore the interface is kept quite identical, extended with some additional functions.
|
|
The goal of the library is to minimize footprint and improve performance.
|
|
This is partly done by dedicate the library to I2C only.
|
|
|
|
The library implements the print interface, so all data types are printable
|
|
assuming they fit on the display.
|
|
|
|
The reference:
|
|
|
|
- https://github.com/fmalpartida/New-LiquidCrystal
|
|
|
|
|
|
#### Compatibility
|
|
|
|
Reasonable compatible with F. Malpartida's I2C library, relative minor differences
|
|
mostly in the constructors.
|
|
Furthermore the current version does not support all functionality, and
|
|
more important it is not tested as much as the reference.
|
|
Only the 5x8 font is supported.
|
|
|
|
So if you need full functionality, robustness or reliability, you still should use
|
|
the reference **New-liquidCrystal** library.
|
|
|
|
|
|
#### Tests
|
|
|
|
Tested on an UNO and a 20x4 character LCD, and limited on a 16x2 LCD.
|
|
|
|
|
|
## Performance
|
|
|
|
The most important optimization is to send every byte in a single I2C transaction.
|
|
This takes 5 bytes to transport, which is 3 less than the reference.
|
|
|
|
Furthermore there is an optimization if the pins are in ascending order, as then
|
|
it is far easier to get the nibble (half bytes) to send.
|
|
|
|
First performance tests are good. See example **I2C_LCD_performance.ino**.
|
|
|
|
The performance measurement is done on an UNO, pins are in order, 0.1.0 version.
|
|
|
|
| I2C clock | 0.1.0 | 0.1.1 | notes |
|
|
|:-----------:|:-----------:|:-----------:|:-------:|
|
|
| 100000 | 4316 | 4640 |
|
|
| 200000 | 2440 | 2760 |
|
|
| 300000 | 1780 | 2108 |
|
|
| 400000 | 1496 | 1820 | (1)
|
|
| 500000 | 1308 | 1632 |
|
|
| 600000 | 1176 | 1500 |
|
|
| 700000 | 1076 | 1400 |
|
|
| 800000 | 1024 | 1348 |
|
|
|
|
Note 1: 0.1.0 problems with spectrum examples - too much data too fast killed my display.
|
|
|
|
Timing in the 0.1.1 version is roughly 10% slower than 0.1.0,
|
|
however the 0.1.1 is more robust as far as tested.
|
|
|
|
|
|
#### Related
|
|
|
|
- https://github.com/fmalpartida/New-LiquidCrystal
|
|
|
|
|
|
## Interface
|
|
|
|
```cpp
|
|
#include "I2C_LCD.h"
|
|
```
|
|
|
|
#### Constructor
|
|
|
|
- **I2C_LCD(uint8_t address, TwoWire \* wire = &Wire)** Constructor,
|
|
mandatory address and optional alternative I2C bus.
|
|
- **void config(uint8_t address, uint8_t enable, uint8_t readWrite, uint8_t registerSelect,
|
|
uint8_t data4, uint8_t data5, uint8_t data6, uint8_t data7,
|
|
uint8_t backlight, uint8_t policy)** pin configuration.
|
|
Will change in the future.
|
|
- **void begin(uint8_t cols = 20, uint8_t rows = 4)** initializes library size.
|
|
User must call the appropriate **Wire.begin()** before calling **lcd.begin(()**
|
|
- **bool isConnected()** returns true if address can be seen on the I2C bus chosen.
|
|
|
|
|
|
#### Backlight
|
|
|
|
- **void setBacklightPin (uint8_t pin, uint8_t policy)**
|
|
policy not implemented yet.
|
|
- **void setBacklight(bool on)** idem.
|
|
- **void backlight()** wrapper for setBacklight()
|
|
- **void noBacklight()** wrapper for setBacklight()
|
|
|
|
|
|
#### Display
|
|
|
|
- **void display()** set display on
|
|
- **void noDisplay()** set display off
|
|
- **void on()** set display on
|
|
- **void off()** set display off
|
|
|
|
|
|
#### Positioning and cursor
|
|
|
|
- **void clear()** clear whole screen and set cursor to 0, 0.
|
|
- **void clearEOL()** clears line from current pos. **NEW**
|
|
- **void home()** set cursor to 0, 0.
|
|
- **bool setCursor(uint8_t col, uint8_t row)** set cursor to given position.
|
|
There is a check if this is out of range, if so it return false.
|
|
- **void noBlink()** idem.
|
|
- **void blink()** idem.
|
|
- **void noCursor()** idem.
|
|
- **void cursor()** idem.
|
|
|
|
|
|
#### Miscellaneous
|
|
|
|
Minimal tested.
|
|
|
|
- **void scrollDisplayLeft(void)**
|
|
- **void scrollDisplayRight(void)**
|
|
- **void moveCursorRight(void)**
|
|
- **void moveCursorLeft(void)**
|
|
|
|
The next 4 have only limited support
|
|
(either autoscroll or leftright can be set, not both)
|
|
|
|
- **void autoscroll(void)**
|
|
- **void noAutoscroll(void)**
|
|
- **void leftToRight(void)**
|
|
- **void rightToLeft(void)**
|
|
|
|
|
|
#### Create your own characters
|
|
|
|
A charmap consists of an array of 8 bytes with values 0..31 (5 bits).
|
|
There are 8 slots to place a special character, indec 0..7.
|
|
|
|
- **void createChar(uint8_t index, uint8_t \* charmap)**
|
|
- **size_t special(uint8_t index)** to print the special char.
|
|
|
|
|
|
index = 0..7, charmap = 8 bytes (0..31)
|
|
|
|
To be printed with
|
|
- **lcd.write((uint8_t)index)** or simpler
|
|
- **lcd.special(index)** wrapper.
|
|
|
|
|
|
#### Print interface
|
|
|
|
- **size_t write(uint8_t c)**
|
|
|
|
Array writing not implemented as there are no gains seen.
|
|
|
|
|
|
## Experimental
|
|
|
|
#### Position tracking
|
|
|
|
The library tries to keep track of the current position on the line it is.
|
|
When going beyond the number of columns, it will not print any more.
|
|
This protects against printing beyond screen position (and writing
|
|
one some other line).
|
|
Additional it saves some time.
|
|
|
|
This position tracking only works for "standard" use, no display
|
|
scrolling, right to left mode etc.
|
|
So it can cause unwanted side effects, which can be fixed by removing
|
|
the "pos < cols" condition from **write()**.
|
|
|
|
- **uint8_t getColumn()**
|
|
|
|
The library does not track the row (yet)
|
|
|
|
#### Tab printing
|
|
|
|
Experimental,
|
|
When '\t' (character 9) is printed to the LCD, it moves to the first position
|
|
that is a multiple of 4.
|
|
This allows a simple way to get some sort of tabular data representation.
|
|
See the example.
|
|
|
|
Idea for the future might be to set the tab-stops instead of current hardcoded ones.
|
|
|
|
|
|
#### DEBUG getWriteCount()
|
|
|
|
As I encountered problems during tests (display garbled) I added a counter
|
|
of the number of writes (each char => 5 bytes I2C).
|
|
For now a development only, so expect it to be removed in future.
|
|
|
|
- **uint32_t getWriteCount()** idem.
|
|
|
|
Not reset-able (yet).
|
|
|
|
|
|
## Future
|
|
|
|
#### Must
|
|
|
|
- update documentation
|
|
|
|
#### Should
|
|
|
|
- test, test, test
|
|
- test with other platforms
|
|
- test with other display sizes
|
|
- test more
|
|
- fix TODO's in code
|
|
- investigate/implement polarity
|
|
- merge low level transport into one if possible
|
|
- add table of new functions not in the reference.
|
|
|
|
|
|
#### Could
|
|
|
|
- add examples
|
|
- Wire1, Wire2 etc
|
|
- make an issue for New-LiquidCrystal library.
|
|
- function to define the tab-stops, instead of hard coded ones.
|
|
- investigate other special characters to support, like
|
|
- \r => goto begin of current line
|
|
- \n => goto begin of next line
|
|
- FF => form feed is clear screen.
|
|
- BELL => blink of the display (oeps 7 is already a special char )
|
|
- make a separate include file for charmaps by name.
|
|
- lcd.center(row, char \* str);
|
|
- lcd.rightAlign(col, row, pos, char \* str);
|
|
|
|
|
|
#### Wont for now.
|
|
|
|
- implement unit tests (possible?)
|
|
- add timestamp last print
|
|
|
|
|
|
## Support
|
|
|
|
If you appreciate my libraries, you can support the development and maintenance.
|
|
Improve the quality of the libraries by providing issues and Pull Requests, or
|
|
donate through PayPal or GitHub sponsors.
|
|
|
|
Thank you,
|
|
|