Difference between revisions of "Unit I2CLCD"

Revision as of 06:18, 21 July 2021

`I2CLCD_PIN_RS = GPIO_PIN_0;`	GPIO pin for the LCD RS line
`I2CLCD_PIN_RW = GPIO_PIN_1;`	GPIO pin for the LCD RW line
`I2CLCD_PIN_EN = GPIO_PIN_2;`	GPIO pin for the LCD EN line
`I2CLCD_PIN_BACKLIGHT = GPIO_PIN_3;`	GPIO pin for the LCD Backlight
`I2CLCD_PIN_D4 = GPIO_PIN_4;`	GPIO pin for the LCD D4 line
`I2CLCD_PIN_D5 = GPIO_PIN_5;`	GPIO pin for the LCD D5 line
`I2CLCD_PIN_D6 = GPIO_PIN_6;`	GPIO pin for the LCD D6 line
`I2CLCD_PIN_D7 = GPIO_PIN_7;`	GPIO pin for the LCD D7 line

I2CLCD display

PI2CLCDDisplay = ^TI2CLCDDisplay;

TI2CLCDDisplay = record

`Signature:LongWord;`	Signature for entry validation
`Width:LongWord;`	Width in columns of this display
`Height:LongWord;`	Height in rows of this display
`I2C:PI2CDevice;`	I2C device for this display
`GPIO:PGPIODevice;`	GPIO (PCF8574) device for this display
`Console:PConsoleDevice;`	Console (HD44780) device for this display

I2CLCD specific variables

`I2CLCD_AUTOSTART:LongBool = True;`	If True then auto start the I2CLCD device on boot

`I2CLCD_I2C_ADDRESS:Word = $27;`

`I2CLCD_I2C_DEVICE:String = 'I2C0';`

`I2CLCD_LCD_WIDTH:LongWord = 16;`

`I2CLCD_LCD_HEIGHT:LongWord = 2;`

Initialization functions

procedure I2CLCDInit;

Description: Initialize the I2CLCD unit and parameters

Note	Called only during system startup

function I2CLCDStart(const Device:String; Address:Word; Width,Height:LongWord):THandle;

Description: Start the I2CLCD driver and register the GPIO and Console devices associated with the display

Device	The I2C device that the PCF8574 I/O Expander on the display is connected to
Address	The I2C address of the PCF8574 I/O Expander on the display
Width	The width in columns of the HD44780 LCD on the display
Height	The height in rows of the HD44780 LCD on the display
Return	The handle of the I2CLCD on success or INVALID_HANDLE_VALUE on failure
Note	This function will be called during startup if the parameter I2CLCD_AUTOSTART is True. Can be called multiple times to support more than one LCD display.

function I2CLCDStop(Handle:THandle):Boolean;

Description: Stop the I2CLCD driver and deregister the GPIO and Console devices associated with the display

Handle	The handle of the I2CLCD or INVALID_HANDLE_VALUE for the default display
Return	True if completed or False on failure

I2CLCD functions

function I2CLCDBacklightOn(Handle:THandle):Boolean;

Description: Turn on the backlight on the I2CLCD display

Handle	The handle of the I2CLCD or INVALID_HANDLE_VALUE for the default display
Return	True if completed or False on failure

function I2CLCDBacklightOff(Handle:THandle):Boolean;

Description: Turn off the backlight on the I2CLCD display

Handle	The handle of the I2CLCD or INVALID_HANDLE_VALUE for the default display
Return	True if completed or False on failure

@@ Line 75: / Line 75: @@
 ----
-''To be documented''
+'''I2CLCD display'''
+<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial;">
+<code>PI2CLCDDisplay = ^TI2CLCDDisplay;</code>
+<code>TI2CLCDDisplay = 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>
+| style="width: 50%;"|Signature for entry validation
+|-
+| <code>Width:LongWord;</code>
+| Width in columns of this display
+|-
+| <code>Height:LongWord;</code>
+| Height in rows of this display
+|-
+| <code>I2C:PI2CDevice;</code>
+| I2C device for this display
+|-
+| <code>GPIO:PGPIODevice;</code>
+| GPIO (PCF8574) device for this display
+|-
+| <code>Console:PConsoleDevice;</code>
+| Console (HD44780) device for this display
+|-
+|}
+</div></div>
+<br />
 === Public variables ===

`I2CLCD_CONSOLE_DESCRIPTION = 'Generic I2C LCD';`	Description of I2CLCD device
`I2CLCD_SIGNATURE = $00CF8574;`