Unit AF16x2LCD

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Description

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Adafruit 16x2 Character LCD + Keypad Driver unit

The Adafruit 16x2 LCD + Keypad is a kit that includes both a 16x2 LCD display using the Hitachi HD44780 LCD controller as well as a custom PCB with an MCP23017 I/O expander to connect it to a Raspberry Pi (any model) using I2C. It is available in Monochrome or RGB Positive and Negative versions.

This unit ties together the various components needed to make one of these boards work with Ultibo by finding the correct I2C device, creating the MCP230XX GPIO device, creating the HD44780 Console device and registering all of it with the correct parameters for the Adafruit kit.

The unit also includes functions to read the 5 buttons on the board and control the LCD backlight.

You will find many LCD display boards based on the Hitachi HD44780 controller and this unit gives an example of how to assembler the available units to create your own driver for a different board.

Constants

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AF16x2LCD specific constants AF16X2LCD_*

AF16X2LCD_CONSOLE_DESCRIPTION = 'Adafruit 16x2 LCD';	Description of AF16x2LCD device
AF16X2LCD_SIGNATURE = $000AF162;
AF16X2LCD_MODEL_MONO = 0;	LCD with Monochrome backlight
AF16X2LCD_MODEL_RGB = 1;	LCD with RGB backlight;

AF16x2LCD GPIO pin GPIO_PIN_*

AF16X2LCD_PLATE_RS = GPIO_PIN_15;	GPIO pin for the LCD RS line
AF16X2LCD_PLATE_RW = GPIO_PIN_14;	GPIO pin for the LCD RW line
AF16X2LCD_PLATE_EN = GPIO_PIN_13;	GPIO pin for the LCD EN line
AF16X2LCD_PLATE_D4 = GPIO_PIN_12;	GPIO pin for the LCD D4 line
AF16X2LCD_PLATE_D5 = GPIO_PIN_11;	GPIO pin for the LCD D5 line
AF16X2LCD_PLATE_D6 = GPIO_PIN_10;	GPIO pin for the LCD D6 line
AF16X2LCD_PLATE_D7 = GPIO_PIN_9;	GPIO pin for the LCD D7 line
AF16X2LCD_PLATE_RED = GPIO_PIN_6;	GPIO pin for the Backlight Red LED
AF16X2LCD_PLATE_GREEN = GPIO_PIN_7;	GPIO pin for the Backlight Green LED
AF16X2LCD_PLATE_BLUE = GPIO_PIN_8;	GPIO pin for the Backlight Blue LED
AF16X2LCD_BUTTON_SELECT = GPIO_PIN_0;	GPIO pin for the Select button
AF16X2LCD_BUTTON_RIGHT = GPIO_PIN_1;	GPIO pin for the Right button
AF16X2LCD_BUTTON_DOWN = GPIO_PIN_2;	GPIO pin for the Down button
AF16X2LCD_BUTTON_UP = GPIO_PIN_3;	GPIO pin for the Up button
AF16X2LCD_BUTTON_LEFT = GPIO_PIN_4;	GPIO pin for the Left button

Type definitions

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AF16x2LCD specific types

PAF16x2LCDPlate = ^TAF16x2LCDPlate;

TAF16x2LCDPlate = record

Signature:LongWord;	Signature for entry validation
Model:LongWord;	Plate model (eg AF16X2LCD_MODEL_MONO)
Invert:LongBool;	Invert polarity of Backlight (Active low if True)
I2C:PI2CDevice;	I2C device for this plate
GPIO:PGPIODevice;	GPIO (MCP23017) device for this plate
Console:PConsoleDevice;	Console (HD44780) device for this plate

Public variables

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AF16x2LCD specific variables

AF16X2LCD_MODEL:LongWord = AF16X2LCD_MODEL_RGB;

AF16X2LCD_I2C_ADDRESS:Word = $20;

AF16X2LCD_I2C_DEVICE:String = 'I2C0';

Function declarations

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Initialization functions

procedure AF16x2LCDInit;

Description: Initialize the AF16x2LCD unit and parameters

Note	Called only during system startup

function AF16x2LCDStart(Model:LongWord; Invert:Boolean; const Device:String; Address:Word):THandle;

Description: Start the AF16x2LCD driver and register the GPIO and Console devices associated with the display

Model	The Adafruit 16x2 LCD Plate model (eg AF16X2LCD_MODEL_RGB)
Invert	Invert the signal level for the LCD backlight (If True then GPIO_LEVEL_LOW equals On)
Device	The I2C device that the MCP23017 I/O Expander on the LCD Plate is connected to
Address	The I2C address of the MCP23017 I/O Expander on the LCD Plate
Return	The handle of the AF16x2LCD on success or INVALID_HANDLE_VALUE on failure
Note	This function will be called during startup if the parameter AF16X2LCD_AUTOSTART is True Can be called multiple times to support more than one 16x2 LCD display

function AF16x2LCDStop(Handle:THandle):Boolean;

Description: Stop the AF16x2LCD driver and deregister the GPIO and Console devices associated with the display

Handle	The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
Return	True if completed or False on failure

AF16x2LCD functions

function AF16x2LCDGetButton(Handle:THandle; Button:LongWord):LongWord;

Description: Get the GPIO level of a button on the AF16x2LCD display

Handle	The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
Button	The button to get the level for (eg AF16X2LCD_BUTTON_LEFT)
Return	The GPIO level of the button (eg GPIO_LEVEL_HIGH) or GPIO_LEVEL_UNKNOWN on failure

function AF16x2LCDBacklightOn(Handle:THandle):Boolean;

Description: Turn on the backlight on the AF16x2LCD display

Handle	The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
Return	True if completed or False on failure

function AF16x2LCDBacklightOff(Handle:THandle):Boolean;

Description: Turn off the backlight on the AF16x2LCD display

Handle	The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
Return	True if completed or False on failure

function AF16x2LCDBacklightColor(Handle:THandle; Red,Green,Blue:Byte):Boolean;

Description: Set the backlight color on the AF16x2LCD display

Handle	The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
Red	The Red value (0 for Off/1 for On)
Green	The Green value (0 for Off/1 for On)
Blue	The Blue value (0 for Off/1 for On)
Return	True if completed or False on failure

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