; RB0-DB4, RB1-DB5, RB2-DB6, RB3-DB7, RB4-ENABLE, RB5-RS, RB6-RW
;16 MHz


	list p=16F628 ; list directive to define processor
#include p16F628.inc ; processor specific variable definitions

	errorlevel -302 ; suppress message 302 from list file 
	__config _HS_OSC &_CP_OFF &_WDT_OFF &_MCLRE_OFF &_BODEN_OFF &_LVP_OFF

		cblock	0x20		;start of general purpose registers
			count			;used in looping routines
			count1			;used in delay routine
			counta			;used in delay routine
			countb			;used in delay routine
			tmp1			;temporary storage
			tmp2
			templcd			;temp store for 4 bit mode
			templcd2
			endc

LCD_PORT	Equ	PORTB
LCD_TRIS	Equ	TRISB
SW_PORT		Equ	PORTA

LCD_RS		Equ	0x05			;LCD handshake lines
LCD_RW		Equ	0x06
LCD_E		Equ	0x04
SW1			Equ	0x02

		org	0x0000

		movlw	0x07
		movwf	CMCON			;turn comparators off (make it like a 16F84)

Initialise	
		clrf	PORTA
		clrf	PORTB
		clrf	count



SetPorts	
		bsf 	STATUS,		RP0	;select bank 1
		movlw	0x00			;make all pins outputs
		movwf	TRISB
		movlw 	0xff
		movwf	SW_PORT
		bcf 	STATUS,		RP0	
		call	Delay100 ; LCD-re varas	



		call	LCD_Init
		call 	text
ciklus
		
		btfsc	SW_PORT, SW1
		goto	ide
		;goto	lcd2
;		btfss	SW_PORT, SW1	
;		goto	lcd1
		goto	ciklus	
ide		
		call	LCD_Clr
		call	LCD_Line2
		call	text
ide2	goto	ide2




;lcd1
;		call	LCD_Clr
;		call	LCD_Cmd		
;		call	LCD_Line1
;		call	LCD_Cmd	
;		call	text	
;		retlw	0x00			

;lcd2	
;		call	LCD_Clr
;		call	LCD_Cmd		
;		call	LCD_Line2
;		call	LCD_Cmd	
;		call	text	
;		retlw	0x00

		

;inicializalas

;Initialise LCD
LCD_Init	
		movlw	0x20			;Set 4 bit mode
		call	LCD_Cmd

		movlw	0x28			;Set display shift
		call	LCD_Cmd

		movlw	0x06			;Set display character mode
		call	LCD_Cmd

		movlw	0x0d			;Set display on/off and cursor command
		call	LCD_Cmd

		call	LCD_Clr			;clear display

		retlw	0x00

; command set routine
LCD_Cmd
		movwf	templcd
		swapf	templcd,	w	;send upper nibble
		andlw	0x0f			;clear upper 4 bits of W
		movwf	LCD_PORT
		bcf		LCD_PORT, LCD_RS	;RS line to 0
		call	Pulse_e			;Pulse the E line high

		movf	templcd,	w	;send lower nibble
		andlw	0x0f			;clear upper 4 bits of W
		movwf	LCD_PORT
		bcf		LCD_PORT, LCD_RS	;RS line to 0
		call	Pulse_e			;Pulse the E line high
		call 	LCD_Busy
		retlw	0x00

LCD_Char	
		movwf	templcd			;display character in W register
		swapf	templcd,	w	;send upper nibble
		andlw	0x0f			;clear upper 4 bits of W
		movwf	LCD_PORT
		bsf		LCD_PORT, LCD_RS	;RS line to 1
		call	Pulse_e			;Pulse the E line high

		movf	templcd,	w	;send lower nibble
		andlw	0x0f			;clear upper 4 bits of W
		movwf	LCD_PORT
		bsf		LCD_PORT, LCD_RS	;RS line to 1
		call	Pulse_e			;Pulse the E line high
		call 	LCD_Busy
		retlw	0x00


LCD_Clr	
		movlw	0x01			;Clear display
		call	LCD_Cmd
		retlw	0x00

		
Pulse_e		
		bsf	LCD_PORT, LCD_E
		nop
		bcf	LCD_PORT, LCD_E
		retlw	0x00

LCD_Busy
		bsf	STATUS,	RP0		;set bank 1
		movlw	0x0f			;set Port for input
		movwf	LCD_TRIS
		bcf	STATUS,	RP0		;set bank 0
		bcf	LCD_PORT, LCD_RS	;set LCD for command mode
		bsf	LCD_PORT, LCD_RW	;setup to read busy flag
		bsf	LCD_PORT, LCD_E
		swapf	LCD_PORT, w		;read upper nibble (busy flag)
		bcf	LCD_PORT, LCD_E		
		movwf	templcd2 
		bsf	LCD_PORT, LCD_E		;dummy read of lower nibble
		bcf	LCD_PORT, LCD_E
		btfsc	templcd2, 7		;check busy flag, high = busy
		goto	LCD_Busy		;if busy check again
		bcf	LCD_PORT, LCD_RW
		bsf	STATUS,	RP0		;set bank 1
		movlw	0x00			;set Port for output
		movwf	LCD_TRIS
		bcf	STATUS,	RP0		;set bank 0
		return

LCD_Line1

		movlw	0x80			;move to 1st row, first column
		call	LCD_Cmd
		retlw	0x00

LCD_Line2
		movlw	0xc0			;move to 2nd row, first column
		call	LCD_Cmd
		retlw	0x00

text	

		movlw	'D'
		call	LCD_Char
		movlw	0x45
		call	LCD_Char
		movlw	0x4E
		call	LCD_Char
		movlw	0x49
		call	LCD_Char
		movlw 	0x53
		call	LCD_Char
		movlw	0x5A
		call	LCD_Char	
		retlw	0x00

	

Delay255	
		movlw	0xff		;delay 255 mS
		goto	d0
Delay100
		movlw	d'100'		;delay 100mS
		goto	d0
Delay50		
		movlw	d'50'		;delay 50mS
		goto	d0
Delay20		
		movlw	d'20'		;delay 20mS
		goto	d0
Delay5		
		movlw	0x05		;delay 5.000 ms (4 MHz clock)
d0		movwf	count1
d1		movlw	0xC7			;delay 1mS
		movwf	counta
		movlw	0x01
		movwf	countb
Delay_0
		decfsz	counta, f
		goto	$+2
		decfsz	countb, f
		goto	Delay_0

		decfsz	count1	,f
		goto	d1
		retlw	0x00

		end