connecting a LM1100SYL 4x20 LCD to the 8535

assume the LM1100SYL from SOLOMON, a 4x20 LCD with LED backlight being connected as :

; Display
;  PORTC	:parallel I/O bidirectional
;  PD5 : output :RS
;  PD6 : output :RW
;  PD7 : output :E

then the following macros are used :

.MACRO LCD_E_Lo
	cbi	portd,7
.ENDMACRO

.MACRO LCD_E_Hi
	sbi	portd,7
.ENDMACRO

.MACRO LCD_RW_Lo
	cbi	portd,6
.ENDMACRO

.MACRO LCD_RW_Hi
	sbi	portd,6
.ENDMACRO

.MACRO LCD_RS_Lo
	cbi	portd,5
.ENDMACRO

.MACRO LCD_RS_Hi
	sbi	portd,5
.ENDMACRO

and the code in an own unit :

U1, U2, U3 & temp are in R15 - R25, and my other macros apply

################################################################

;
;module for LCD LM1100SYL
;
;   LCD : line1, line3, line2, line 4
;line1 :$00 =0
;line2: $40 =64
;line3: $14 =20
;line4: $54 =84
;
.equ	_LCD_Clear	=0x01	;
.equ	_LCD_Off	=0x08	;
.equ	_LCD_On		=0x0C	;
.equ	_LCD_OnC	=0x0E	;with cursor
.equ	_LCD_OnB	=0x0D	;with blink
;
;
;
;;wait 100us  - 118us
Wait100n:
	push	u1
	push	u2
	ldi	u1,2
wn1:	ldi	u2,70
wn2:	dec	u2
	brne	wn2
	dec	u1
	brne	wn1
	pop	u2
	pop	u1
	ret
;write instruction to LCD, instruction in U1
LCD_WI:
	out	PortC,U1	;instruction to port
	ser	temp
	out	DDRC,temp	;portC:=output
	LCD_RS_Lo
	LCD_RW_Lo
	LCD_E_Hi
	nop
	nop
	nop
	LCD_E_Lo
	LCD_RW_Hi
	clr	temp
	out	DDRC,temp	;portC:=input
	ret


;write data to LCD, data in U1
LCD_WD:
	out	PortC,U1	;instruction to port
	ser	temp
	out	DDRC,temp	;portC:=output
	LCD_RS_Hi
	LCD_RW_Lo
	LCD_E_Hi
	nop
	nop
	nop
	LCD_E_Lo
	LCD_RW_Hi
	clr	temp
	out	DDRC,temp	;portC:=input
	ret

;reads LCD status
LCD_RI:
	clr	temp
	out	PORTC,temp
	out	DDRC,temp	;portC:=input
	LCD_RS_Lo
	LCD_RW_Hi
	LCD_E_Hi
	nop
	nop
	in	U1,PortC	;instruction to port
	nop
	nop
	LCD_E_Lo
	LCD_RW_Hi
	ret

;reads LCD data
LCD_RD:
	clr	temp
	out	DDRC,temp	;portC:=input
	LCD_RS_Hi
	LCD_RW_Hi
	LCD_E_Hi
	nop
	nop
	in	U1,PortC	;instruction to port
	nop
	LCD_E_Lo
	LCD_RW_Hi
	ret

; wait while LCD busy
LCD_wait:
	push	U1
	clr	temp
	out	PORTC,temp
	out	DDRC,temp	;portC:=input
ww1:	LCD_RS_Lo
	LCD_RW_Hi
	LCD_E_Hi
	nop
	nop
	in	U1,PinC	;instruction to port
	nop
	LCD_E_Lo
	LCD_RW_Hi
	andi	u1,0x80
	brne	ww1
	pop	U1
	ret

; initialize LCD - more than 15ms after power up
LCD_Init:
; function set
	ldi	u1,0x3F	; function set
	rcall	LCD_WI
;  wait more than 4.1ms
	ldi	u1,40
aa2:	rcall	Wait100n
	dec	u1
	brne	aa2
	ldi	u1,0x3F	; function set
	rcall	LCD_WI
	rcall	Wait100n	; wait more than 100us

	ldi	u1,0x3F	; function set
	rcall	LCD_WI
	rcall	wait100n	; wait more than 100us
	ldi	u1,_LCD_Off	; off
	rcall	LCD_WI
	rcall	LCD_wait
	ldi	u1,_LCD_Clear	;clear
	rcall	LCD_WI
	rcall	LCD_wait
	ldi	u1,0x06 ;increment, 
	rcall	LCD_WI
	rcall	LCD_wait
	ldi	u1,_LCD_OnC	;
	rcall	LCD_WI
	rcall	LCD_wait
	ret

; set LCD adress U1
LCD_Adr:
	ori	U1,0x80
	rcall	LCD_WI
	rcall	LCD_wait
	ret

; display char U1
LCD_Char:
	rcall	LCD_WD
	rcall	LCD_wait
	ret


; display char U1 at adr U2
LCD_CharAtAdr:
	push	U1
	mov	U1,U2
	ori	U1,0x80
	rcall	LCD_WI
	rcall	LCD_wait
	rcall	wait100n
	rcall	wait100n
	pop	u1
	rcall	LCD_WD
	rcall	LCD_wait
	ret

; display char U1 at (x,y) U2,U3
LCD_CharXY:
	cpi	u3,1	;test 1st line
	brne	cxy1
; 1st line
	rcall	LCD_CharAtAdr
	rjmp	cxye
cxy1:	cpi	u3,2	;test 2ns line
	brne	cxy2
	ldi	u3,0x40
	add	u2,u3
	rcall	LCD_CharAtAdr
	rjmp	cxye
cxy2:	cpi	u3,3	;test 3rd line
	brne	cxy3
	ldi	u3,0x14
	add	u2,u3
	rcall	LCD_CharAtAdr
	rjmp	cxye
cxy3:	cpi	u3,4	;test 4th line
	brne	cxye
	ldi	u3,0x54
	add	u2,u3
	rcall	LCD_CharAtAdr
cxye:	ret

;display string Z^ at line U2
LCD_StringY:
	push	YL
	push	YH
	mov	YL,ZL
	mov	YH,ZH
	push	U4
	push	U1
	cpi	u2,1	;test 1st line
	brne	csy1
	ldi	U1,0
	rcall	LCD_Adr
	ld	u4,Z+	;length
	tst	U4
	breq	csye
csl1:	ld	u1,Z+
	rcall	LCD_Char
	dec	u4
	brne	csl1
	rjmp	csye
csy1:	cpi	u2,2	;test 2ns line
	brne	csy2
	ldi	u1,0x40
	rcall	LCD_Adr
	ld	u4,Z+
csl2:	ld	u1,Z+
	rcall	LCD_Char
	dec	u4
	brne	csl2
	rjmp	csye
csy2:	cpi	u2,3	;test 3rd line
	brne	csy3
	ldi	u1,0x14
	rcall	LCD_Adr
	ld	u4,Z+
csl3:	ld	u1,Z+
	rcall	LCD_Char
	dec	u4
	brne	csl3
	rjmp	csye
csy3:	cpi	u2,4	;test 4th line
	brne	csye
	ldi	u1,0x54
	rcall	LCD_Adr
	ld	u4,Z+
csl4:	ld	u1,Z+
	rcall	LCD_Char
	dec	u4
	brne	csl4
csye:	pop	U1
	pop	U4
	mov	ZL,YL
	mov	ZH,YH
	pop	YH
	pop	YL
	ret

; cursor off
LCD_CursorOff:
	push	U1
	ldi	U1,_LCD_On
	rcall	LCD_WI
	pop	U1
	rcall	LCD_Wait
	ret

; cursor off
LCD_CursorOn:
	push	U1
	ldi	U1,_LCD_OnC
	rcall	LCD_WI
	pop	U1
	rcall	LCD_Wait
	ret

; set cursor	(x,y)=U1,U2
LCD_CursorXY:
	rcall	LCD_CursorOn
	cpi	U2,1
	brne	ccxy1
; cursor on 1st line
	rcall	LCD_Adr
	ret
ccxy1:	cpi	U2,2
	brne	ccxy2
; cursor on 2nd line
	ldi	U2,0x40
	add	U1,U2
	rcall	LCD_Adr
	ret
ccxy2:	cpi	U2,3
	brne	ccxy3
; cursor on 3rd line
	ldi	U2,0x14
	add	U1,U2
	rcall	LCD_Adr
	ret
ccxy3:	cpi	U2,4
	brne	ccxye
; cursor on 4th line
	ldi	U2,0x54
	add	U1,U2
	rcall	LCD_Adr
ccxye:	ret

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