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Description
Hitachi HD44780 LCD Controller Driver unit
The Hitachi HD44780 is a dot matrix liquid crystal display controller. It supports 5x8 or 5x10 characters and includes a 240 character font in ROM, 80 bytes of character RAM and 64 bytes of character generator RAM for custom characters.
The device support 4 bit or 8 bit modes, and has a range of standard functions for display clear, display on/off, cursor on/off, character blink, cursor shift etc.
This unit creates a Console device to represent the LCD and provides the standard console device functions (where appropriate) to draw text, clear the screen, scroll text and manage the cursor.
Currently only 4 bit mode is supported but extension to include 8 bit mode is possible with some additional setup and support functions.
Constants
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HD44780 specific constants HD44780_CONSOLE_*
HD44780_CONSOLE_DESCRIPTION = 'Hitachi HD44780 LCD Controller';
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Description of HD44780 device
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HD44780 instruction HD44780_*
HD44780_CLEARDISPLAY = $01;
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HD44780_RETURNHOME = $02;
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HD44780_ENTRYMODESET = $04;
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HD44780_DISPLAYCONTROL = $08;
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HD44780_CURSORSHIFT = $10;
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HD44780_FUNCTIONSET = $20;
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HD44780_SETCGRAMADDR = $40;
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HD44780_SETDDRAMADDR = $80;
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HD44780 entry mode set HD44780_ENTRYMODESET_*
HD44780_ENTRYMODESET_RIGHT = $00;
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HD44780_ENTRYMODESET_LEFT = $02;
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HD44780_ENTRYMODESET_SHIFTINC = $01;
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HD44780_ENTRYMODESET_SHIFTDEC = $00;
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HD44780 display control HD44780_DISPLAYCONTROL_*
HD44780_DISPLAYCONTROL_DISPLAYON = $04;
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HD44780_DISPLAYCONTROL_DISPLAYOFF = $00;
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HD44780_DISPLAYCONTROL_CURSORON = $02;
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HD44780_DISPLAYCONTROL_CURSOROFF = $00;
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HD44780_DISPLAYCONTROL_BLINKON = $01;
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HD44780_DISPLAYCONTROL_BLINKOFF = $00;
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HD44780 cursor shift HD44780_CURSORSHIFT_*
HD44780_CURSORSHIFT_DISPLAY = $08;
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HD44780_CURSORSHIFT_CURSOR = $00;
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HD44780_CURSORSHIFT_RIGHT = $04;
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HD44780_CURSORSHIFT_LEFT = $00;
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HD44780 function set HD44780_FUNCTIONSET_*
HD44780_FUNCTIONSET_8BITMODE = $10;
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HD44780_FUNCTIONSET_4BITMODE = $00;
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HD44780_FUNCTIONSET_2LINE = $08;
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HD44780_FUNCTIONSET_1LINE = $00;
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HD44780_FUNCTIONSET_5X10DOTS = $04;
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HD44780_FUNCTIONSET_5X8DOTS = $00;
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HD44780 row offset HD44780_ROW_OFFSETS*
| 4 rows
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HD44780_ROW_OFFSETS:array[0..3] of Byte = ($00,$40,$14,$54);
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Type definitions
HD44780 character
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PHD44780Character = ^THD44780Character;
THD44780Character = array[0..7] of Byte;
HD44780 console
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PHD44780Console = ^THD44780Console;
THD44780Console = record
| Console Properties
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Console:TConsoleDevice;
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| HD44780 Properties
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GPIO:PGPIODevice;
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The GPIO device this Console is connected to
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RS:LongWord;
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The GPIO pin for the RS line
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RW:LongWord;
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The GPIO pin for the RW line
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EN:LongWord;
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The GPIO pin for the EN line
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D4:LongWord;
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The GPIO pin for the D4 line
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D5:LongWord;
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The GPIO pin for the D5 line
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D6:LongWord;
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The GPIO pin for the D6 line
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D7:LongWord;
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The GPIO pin for the D7 line
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EntryMode:Byte;
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Current value of the Entry Mode settings
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FunctionSet:Byte;
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Current value of the Function Set settings
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DisplayControl:Byte;
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Current value of the Display Control settings
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| Cursor Properties
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CursorX:Byte;
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CursorY:Byte;
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| Buffer Properties
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Size:LongWord;
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Buffer:PByte;
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Public variables
None defined
Function declarations
HD44780 functions
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function HD44780ConsoleCreate(GPIO:PGPIODevice; const Name:String; Width,Height,RS,RW,EN,D4,D5,D6,D7:LongWord):PConsoleDevice;
Description: To be documented
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function HD44780ConsoleDestroy(Console:PConsoleDevice):LongWord;
Description: To be documented
HD44780 console functions
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function HD44780ConsoleOpen(Console:PConsoleDevice):LongWord;
Description: Implementation of ConsoleDeviceOpen API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceOpen instead.
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function HD44780ConsoleClose(Console:PConsoleDevice):LongWord;
Description: Implementation of ConsoleDeviceClose API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceClose instead.
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function HD44780ConsoleClear(Console:PConsoleDevice; Color:LongWord):LongWord;
Description: Implementation of ConsoleDeviceClear API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceClear instead.
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function HD44780ConsoleScroll(Console:PConsoleDevice; X1,Y1,X2,Y2,Count,Direction:LongWord):LongWord;
Description: Implementation of ConsoleDeviceScroll API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceScroll instead.
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function HD44780ConsoleDrawChar(Console:PConsoleDevice; Handle:TFontHandle; Ch:Char; X,Y,Forecolor,Backcolor:LongWord):LongWord;
Description: Implementation of ConsoleDeviceDrawChar API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceDrawChar instead.
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function HD44780ConsoleDrawText(Console:PConsoleDevice; Handle:TFontHandle; const Text:String; X,Y,Forecolor,Backcolor,Len:LongWord):LongWord;
Description: Implementation of ConsoleDeviceDrawText API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceDrawText instead.
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function HD44780ConsoleDrawBlock(Console:PConsoleDevice; X1,Y1,X2,Y2,Color:LongWord):LongWord;
Description: Implementation of ConsoleDeviceDrawBlock API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceDrawBlock instead.
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function HD44780ConsoleDrawWindow(Console:PConsoleDevice; Handle:TWindowHandle; Flags:LongWord):LongWord;
Description: Implementation of ConsoleDeviceDrawWindow API for HD44780
| Note
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Caller must hold the Window lock
Not intended to be called directly by applications, use ConsoleDeviceDrawWindow instead.
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function HD44780ConsolePutText(Console:PConsoleDevice; Handle:TFontHandle; const Source,Dest:TConsolePoint; Buffer:PConsoleChar; Width,Height,Skip:LongWord):LongWord;
Description: Implementation of ConsoleDevicePutText API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDevicePutText instead.
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function HD44780ConsoleGetPosition(Console:PConsoleDevice; Position:LongWord; var X1,Y1,X2,Y2:LongWord):LongWord;
Description: Implementation of ConsoleDeviceGetPosition API for HD44780
| Note
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Not intended to be called directly by applications, use ConsoleDeviceGetPosition instead.
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HD44780 helper functions
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function HD44780WriteChar(Console:PHD44780Console; Ch:Char):LongWord;
Description: Write character data to the HD44780 device
| Note
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Caller must hold the Console lock
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function HD44780WriteData(Console:PHD44780Console; Value:Byte):LongWord;
Description: Write command data to the HD44780 device
| Note
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Caller must hold the Console lock
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function HD44780PulseEnable(Console:PHD44780Console):LongWord;
Description: Pulse the clock enable line off, on, off to send a command
| Note
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Caller must hold the Console lock
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function HD44780CursorHome(Console:PHD44780Console):LongWord;
Description: Return the cursor to the top left corner
| Note
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Caller must hold the Console lock
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function HD44780CursorBlink(Console:PHD44780Console; Blink:Boolean):LongWord;
Description: Set the cursor blinking to on or off
| Note
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Caller must hold the Console lock
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function HD44780CursorVisible(Console:PHD44780Console; Visible:Boolean):LongWord;
Description: Set the cursor to visible or not visible
| Note
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Caller must hold the Console lock
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function HD44780CursorPosition(Console:PHD44780Console; Row,Col:Byte):LongWord;
Description: Set the cursor position to Row, Col
| Note
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Caller must hold the Console lock
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function HD44780DisplayEnabled(Console:PHD44780Console; Enabled:Boolean):LongWord;
Description: Set the display state to on or off
| Note
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Caller must hold the Console lock
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function HD44780AddCharacter(Console:PHD44780Console; Location:Byte; Character:THD44780Character):LongWord;
Description: Add a custom character to the display
| Note
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Caller must hold the Console lock
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