*
* Lcd1.asm ---- 16X2 LCD sample program for the Ep2711E9 Rev.C board
*		(c)2003, EVBplus.com, Written by Wayne Chu
*
*     Function:	This is the simplest way to displays a message on a 
*		16X2 LCD display module. The cursor is off. 
*		If more controls to the display are needed, see LCD2.asm
*     
DB0:		equ	1
DB1:		equ	2
*
                org     $FFA0	; Buffalo I/O routines

upcase:         rmb     3
wchek:          rmb     3
dchek:          rmb     3
init_sci:       rmb     3
input:          rmb     3
output:         rmb     3
outlhlf:        rmb     3
outrhlf:        rmb     3
outa:           rmb     3
out1byt:        rmb     3
out1bsp:        rmb     3
out2bsp:        rmb     3
outcrlf:        rmb     3
outstrg:        rmb     3
outstrg0:	rmb	3
inchar:         rmb     3
*
STACK:		equ	$8FFF

ONE_MS		equ	167	; for 8 MHz    1000us/6us=167
FIVE_MS		equ	835
TEN_MS		equ	1670


PORTF   	equ	$2201
DDRF   		equ	$2203
d40us:		equ	15	; 15x6us= 90 us, 60us ok
REG_SEL:	equ	DB0	; 0=reg, 1=data
ENABLE:		equ     DB1
NOT_REG_SEL:	equ	$FE
NOT_ENABLE:	equ     $FD
  		org	0
temp1:		rmb	1
pfimg:		rmb	1
reset_seq:	rmb	1
disp_ram:	rmb	3
*
LCDimg:		equ	pfimg
LCD_RSimg:	equ	pfimg
LCD_ENimg:	equ	pfimg

LCD:		equ	PORTF
LCD_RS:		equ	PORTF
LCD_EN:		equ	PORTF
*
	org	$D000
	jmp	start

lcd_ini:
	ldaa	#$FF
	staa	DDRF
	clra
	staa	pfimg
	staa	PORTF
       	ldx	#inidsp1   		; point to init. codes.
	ldaa	#1
	staa	reset_seq		; need more delay for first reset seq.
       	jsr    	outins1    		; output codes.
       	ldx	#inidsp2   		; point to init. codes.
	clr	reset_seq
       	jsr    	outins2    		; output codes.
	rts
inidsp1:
	fcb	2		; number of instrutions
	fcb	$33		; reset char
	fcb	$32		; reste char
inidsp2:
	fcb	4		; number of instrutions
	fcb	$28   		; 4bit, 2 line, 5X7 dot
	fcb	$06		; cursor increment, disable display shift
	fcb	$0c		; display on, cursor off, no blinking
	fcb	$01		; clear display memory, set cursor to home pos
outins1:
	pshb            		; output instruction command.
       	jsr    	sel_inst
       	ldab   	0,x
       	inx
onext1:	ldaa   	0,x
       	jsr    	wrt_pulse    		; initiate write pulse.
       	inx
	jsr	d5ms
       	decb
       	bne    	onext1
       	pulb
       	rts
*
outins2:
	pshb            		; output instruction command.
       	jsr    	sel_inst
       	ldab   	0,x
       	inx
onext2:	ldaa   	0,x
       	jsr    	wrt_pulse    		; initiate write pulse.
       	inx
       	decb
       	bne    	onext2
	jsr	d5ms
       	pulb
       	rts
*
delay_10ms:
	nop
d10ms:  pshx
	ldx     #TEN_MS
  	bsr	del1
  	pulx
	rts
d5ms:   pshx
	ldx     #FIVE_MS
  	bsr	del1
	pulx
	rts
del1:	dex
	inx
	dex
	bne	del1
	rts
*
*
sel_data:
	psha
*	bset	LCD_RSimg REG_SEL	; select instruction
	ldaa	LCD_RSimg
	oraa	#REG_SEL
	bra	sel_i
sel_inst:
	psha
*	bclr	LCD_RSimg REG_SEL	; select instruction
	ldaa	LCD_RSimg
	anda	#NOT_REG_SEL
sel_i:	staa	LCD_RSimg
	staa	LCD_RS
	pula
        rts
*

lcd_line1:
	jsr    	sel_inst		; select instruction
       	ldaa   	#$80     		; starting address for the line1
	bra	line3
lcd_line2:
	jsr    	sel_inst
       	ldaa   	#$C0     		; starting address for the line2
line3: 	jsr    	wrt_pulse
*
       	jsr    	sel_data
	jsr	msg_out
	rts

* at entry, x must point to the begining of the message,
*           b = number of the character to be sent out
*
msg_out:
	ldaa   	0,x
       	jsr    	wrt_pulse
       	inx
       	decb
       	bne    	msg_out
	rts

*
*       @ enter, a=data to output
*
wrt_pulse:
	pshx
       	psha        			; save it tomporarily.
       	anda   #$f0     		; mask out 4 low bits.
       	staa   temp1 			; save nibble value.
       	ldaa   LCDimg    		; get LCD port image.
       	anda   #$0f     		; need low 4 bits.
       	oraa   temp1    		; add in low 4 bits.
       	staa   LCDimg    		; save it
       	staa   LCD    			; output data
*
	bsr	enable_pulse
	ldaa	reset_seq
	beq	wrtpls
	jsr	d5ms			; delay for reset sequence
*
wrtpls:	pula
 	asla            		; move low bits over.
	asla
      	asla
       	asla
       	staa   	temp1			; store temporarily.
*
       	ldaa   	LCDimg 			; get LCD port image.
       	anda   	#$0f   			; need low 4 bits.
       	oraa   	temp1  			; add in loiw 4 bits.
       	staa   	LCDimg    		; save it
       	staa   	LCD    			; output data
*
	bsr	enable_pulse
	pulx
       	rts
*
enable_pulse:
*	bset	LCD_ENimg ENABLE	; ENABLE=high
	ldaa	LCD_ENimg
	oraa	#ENABLE
	staa	LCD_ENimg
	staa	LCD_EN
*	bclr	LCD_ENimg ENABLE	; ENABLE=low
	ldaa	LCD_ENimg
	anda	#NOT_ENABLE
	staa	LCD_ENimg
	staa	LCD_EN
	pshx
	ldx     #d40us
  	jsr	del1
	pulx
	rts
*
start:
     	lds	#STACK
   	jsr	delay_10ms	; delay 20ms during power up
    	jsr	delay_10ms

    	jsr	lcd_ini		; initialize the LCD 
                      	
back:	ldx    	#MSG1		; MSG1 for line1, x points to MSG1
        ldab    #16             ; send out 16 characters
    	jsr	lcd_line1
*
    	ldx    	#MSG2		; MSG2 for line2, x points to MSG2
        ldab    #16             ; send out 16 characters
     	jsr	lcd_line2
     	jsr	delay_10ms
     	jsr	delay_10ms
     	jmp	back
                       
MSG1:   FCC     " YOU DESERVE A  "
MSG2:   FCC     "  BREAK TODAY   "
       	
       	end