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;*******************************************************************
;
; LCD
; The information for the LCD software comes from several places: Microchip's AN587,
; Optrex Data Book, Christopher J. Burian's LCD Technical FAQ, and Peer Ouwehand's "How to
; Control HD44780-based Character-LCD".
;
; Microchip can be reached at
; http://www.ultranet.com/biz/mchip/
; Burian's FAQ is located at
; http://www.paranoia.com/~filipg/HTML/LINK/F_LCD_tech.html
; Ouwehand's document is located at
; http://www.iaehv.nl/users/pouweha/lcd.htm
;
;*******************************************************************
Dev_Tcyc EQU 400 ;Tcyc = 400 ns, Instruction Cycle time
Inner_delay EQU (256*3 + 3)*Dev_Tcyc ;The amount of time spent in inner delay loop
LCD_INIT_DELAY EQU 15000000/Inner_delay ;15ms
LCD_CONTROL_PORT EQU PORTB ;LCD control lines interface to PORTB
LCD_DATA_PORT EQU PORTB
;PORTB<7:4> == LCD_DB<7:4> (4 bit mode)
LCD_E EQU 3 ;PORTB<1> == LCD Enable control line
LCD_Eb EQU (1<<LCD_E)
LCD_R_W EQU 2 ;PORTB<2> == LCD Read/Write control line
LCD_RS EQU 1 ;PORTB<3> == LCD Register Select control line
LCD_CONTROL_MASK EQU (1<<LCD_E) | (1<<LCD_R_W) | (1<<LCD_RS)
;Define the data mask. If the 4-bit LCD data bus is accessible via the high nibble
;of the DATA_PORT then the DATA_MASK should be 0xf0. Otherwise, it should be 0x0f.
;Note, the software will NOT work if the LCD data bus is not nibble-aligned.
LCD_DATA_MASK EQU 0xf0
; if LCD_DATA_MASK == 0xf0
LCD_DATA_SHIFT EQU 0 ;Used to shift the LCD constants.
; else
;LCD_DATA_SHIFT EQU 4
; endif
LCD_CONTROL_TRIS EQU LCD_CONTROL_PORT ;
LCD_DATA_TRIS EQU LCD_DATA_PORT ;
;LCD Command Clear Display = 00000001
LCD_CMD_CLEAR_DISPLAY EQU 0x01
;LCD Command Display Control = 00001dcb
; d = 1 turn display on or 0 to turn display off
; c = 1 turn cursor on or 0 to turn cursor off
; b = 1 blinking cursor or 0 non-blinking cursor
LCD_CMD_DISPLAY_CTRL EQU 0x08 ;LCD Command "Display Control"
LCD_DISPLAY_OFF EQU 0x00 ;d=0
LCD_DISPLAY_ON EQU 0x04 ;d=1
LCD_CURSOR_OFF EQU 0x00 ;c=0
LCD_CURSOR_ON EQU 0x02 ;c=1
LCD_BLINK_OFF EQU 0x00 ;b=0
LCD_BLINK_ON EQU 0x01 ;b=1
;LCD Command Function Set = 001dnfxx
; d = 1 for 8-bit interface or 0 for 4-bit interface
; n = for 2 line displays, n=1 allows both lines to be displayed while n=0 only allows the first.
; f = font size. f=1 is for 5x11 dots while f=0 is for 5x8 dots.
LCD_CMD_FUNC_SET EQU 0x20 ;LCD Command "Function Set"
LCD_4bit_MODE EQU 0x00 ;d=0
LCD_8bit_MODE EQU 0x10 ;d=1
LCD_1_LINE EQU 0x00 ;n=0
LCD_2_LINES EQU 0x08 ;n=1
LCD_SMALL_FONT EQU 0x00 ;f=0
LCD_LARGE_FONT EQU 0x04 ;f=1
;LCD Command "Entry Mode" = 000001is
; i = 1 to increment or 0 to decrement the DDRAM address after each DDRAM access.
; s = 1 to scroll the display in the direction specified by the i-bit when the
; cursor reaches the edge of the display window.
LCD_CMD_ENTRY_MODE EQU 0x04 ;LCD Command "Entry Mode"
LCD_DEC_CURSOR_POS EQU 0x00 ;i=0
LCD_INC_CURSOR_POS EQU 0x02 ;i=1
LCD_NO_SCROLL EQU 0x00 ;s=0
LCD_SCROLL EQU 0x01 ;s=1
;LCD Command "Set Display Data RAM Address" = 10000000
LCD_CMD_SET_DDRAM EQU 0x80
LCD_CMD_SET_CGRAM EQU 0x40
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