View source for Unit AF16x2LCD

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=== Description ===
----

'''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 ===
----


<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
<div style="font-size: 14px; padding-left: 12px;">'''AF16x2LCD specific''' <code> AF16X2LCD_* </code></div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
| <code>AF16X2LCD_CONSOLE_DESCRIPTION = 'Adafruit 16x2 LCD';</code>
| Description of AF16x2LCD device
|-
|colspan="2"|&nbsp;
|-
| <code>AF16X2LCD_SIGNATURE = $000AF162;</code>
| &nbsp;
|-
|colspan="2"|&nbsp;
|-
| <code>AF16X2LCD_MODEL_MONO = 0;</code>
| LCD with Monochrome backlight
|-
| <code>AF16X2LCD_MODEL_RGB = 1;</code>
| LCD with RGB backlight;
|-
|}
</div></div>
<br />
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
<div style="font-size: 14px; padding-left: 12px;">'''AF16x2LCD GPIO pin''' <code> GPIO_PIN_* </code></div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
| <code>AF16X2LCD_PLATE_RS = GPIO_PIN_15;</code>
| GPIO pin for the LCD RS line
|-
| <code>AF16X2LCD_PLATE_RW = GPIO_PIN_14;</code>
| GPIO pin for the LCD RW line
|-
| <code>AF16X2LCD_PLATE_EN = GPIO_PIN_13;</code>
| GPIO pin for the LCD EN line
|-
| <code>AF16X2LCD_PLATE_D4 = GPIO_PIN_12;</code>
| GPIO pin for the LCD D4 line
|-
| <code>AF16X2LCD_PLATE_D5 = GPIO_PIN_11;</code>
| GPIO pin for the LCD D5 line
|-
| <code>AF16X2LCD_PLATE_D6 = GPIO_PIN_10;</code>
| GPIO pin for the LCD D6 line
|-
| <code>AF16X2LCD_PLATE_D7 = GPIO_PIN_9;</code>
| GPIO pin for the LCD D7 line
|-
| <code>AF16X2LCD_PLATE_RED = GPIO_PIN_6;</code>
| GPIO pin for the Backlight Red LED
|-
| <code>AF16X2LCD_PLATE_GREEN = GPIO_PIN_7;</code>
| GPIO pin for the Backlight Green LED
|-
| <code>AF16X2LCD_PLATE_BLUE = GPIO_PIN_8;</code>
| GPIO pin for the Backlight Blue LED
|-
|colspan="2"|&nbsp;
|-
| <code>AF16X2LCD_BUTTON_SELECT = GPIO_PIN_0;</code>
| GPIO pin for the Select button
|-
| <code>AF16X2LCD_BUTTON_RIGHT = GPIO_PIN_1;</code>
| GPIO pin for the Right button
|-
| <code>AF16X2LCD_BUTTON_DOWN = GPIO_PIN_2;</code>
| GPIO pin for the Down button
|-
| <code>AF16X2LCD_BUTTON_UP = GPIO_PIN_3;</code>
| GPIO pin for the Up button
|-
| <code>AF16X2LCD_BUTTON_LEFT = GPIO_PIN_4;</code>
| GPIO pin for the Left button
|-
|}
</div></div>
<br />

=== Type definitions ===
----


'''AF16x2LCD specific types'''

<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial;">
<code>PAF16x2LCDPlate = ^TAF16x2LCDPlate;</code>

<code>TAF16x2LCDPlate = record</code>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
| <code>Signature:LongWord;</code>
| Signature for entry validation
|-
| <code>Model:LongWord;</code>
| Plate model (eg AF16X2LCD_MODEL_MONO)
|-
| <code>Invert:LongBool;</code>
| Invert polarity of Backlight (Active low if True)
|-
| <code>I2C:PI2CDevice;</code>
| I2C device for this plate
|-
| <code>GPIO:PGPIODevice;</code>
| GPIO (MCP23017) device for this plate
|-
| <code>Console:PConsoleDevice;</code>
| Console (HD44780) device for this plate
|-
|}
</div></div>
<br />

=== Public variables ===
----


'''AF16x2LCD specific variables'''

{| class="wikitable" style="font-size: 14px; text-align: left; width: 100%; height: 50px;"
|-
| <code>AF16X2LCD_MODEL:LongWord = AF16X2LCD_MODEL_RGB;</code>
| style="width: 40%;"|
|-
|}
{| class="wikitable" style="font-size: 14px; text-align: left; width: 100%; height: 50px;"
|-
| <code>AF16X2LCD_I2C_ADDRESS:Word = $20;</code>
| style="width: 40%;"|
|-
|}
{| class="wikitable" style="font-size: 14px; text-align: left; width: 100%; height: 50px;"
|-
| <code>AF16X2LCD_I2C_DEVICE:String = 'I2C0';</code>
| style="width: 40%;"|
|-
|}
<br />

=== Function declarations ===
----


'''Initialization functions'''

<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">procedure AF16x2LCDInit;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Initialize the AF16x2LCD unit and parameters</div>
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{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''Note'''
| Called only during system startup
|-
|}
</div></div>
<br /> 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">function AF16x2LCDStart(Model:LongWord;Invert:Boolean; const Device:String; Address:Word):THandle;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Start the AF16x2LCD driver and register the GPIO and Console devices associated with the display</div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''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
|-
|}
</div></div>
<br /> 	   
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">function AF16x2LCDStop(Handle:THandle):Boolean;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Stop the AF16x2LCD driver and deregister the GPIO and Console devices associated with the display</div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''Handle'''
| The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
|-
! '''Return'''
| True if completed or False on failure
|-
|}
</div></div>
<br />

'''AF16x2LCD functions'''

<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">function AF16x2LCDGetButton(Handle:THandle; Button:LongWord):LongWord;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the GPIO level of a button on the AF16x2LCD display</div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''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
|-
|}
</div></div>
<br /> 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">function AF16x2LCDBacklightOn(Handle:THandle):Boolean;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Turn on the backlight on the AF16x2LCD display</div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''Handle'''
| The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
|-
! '''Return'''
| True if completed or False on failure
|-
|}
</div></div>
<br /> 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">function AF16x2LCDBacklightOff(Handle:THandle):Boolean;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Turn off the backlight on the AF16x2LCD display</div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''Handle'''
| The handle of the AF16x2LCD or INVALID_HANDLE_VALUE for the default display
|-
! '''Return'''
| True if completed or False on failure
|-
|}
</div></div>
<br /> 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
<pre style="border: 0; padding-bottom:0px;">function AF16x2LCDBacklightColor(Handle:THandle; Red,Green,Blue:Byte):Boolean;</pre>
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Set the backlight color on the AF16x2LCD display</div>
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
{| class="wikitable" style="font-size: 14px; background: white;"
|-
! '''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
|-
|}
</div></div>
<br />

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