Philip, many 16x1 LCDs works as 8x2, even there are only one line.
As you say, you see only 8 black square it's sure you have to change the
cursor position after 8 writtings to line2.
But "hello" should appear...
See the example f84lcd1.jal ( in jal) from the:
http://www.geocities.com/vsurducan/pic84lcd.htm
Cheers, Vasile

On Sat, 16 Jun 2001, Philip Pemberton wrote:

> Hi PICLISTers,
>     I've just found a Samsung KS0066-based (HD44780-compatible) 16x1 LCD in
> my junk box and I've been trying all afternoon to make my code work. What am
> I doing wrong? I've attached my code to the end of this message (after the
> snips). Compile with MPASM.
> When the LCD and PIC are powered up, the LCD displays 8 black squares on the
> left-hand side of the display. After about half a second, the LCD goes
> completely blank. The text that is sent to the LCD ("Hello") never appears.
> Any ideas?
>
> BTW, this code is for a 4-bit interface. See the pin definitions at the top
> of LCD-4BIT.INC
>
> Thanks in advance.
>
> --8<--- LCD-4BIT.INC
> ; LCD routines
> ; pin assignment for the 4-bit (6 PIC I/O pins) interface:
> ;
> ; PIC        HD44870
> ; ------------------
> ;PIN FUNCTION       PIN FUNCTION
> ;  5 Gnd              1 Gnd
> ; 14 Vcc              2 Vcc
> ;  5 Gnd              3 Contrast
> ;  6 B0              11 D4
> ;  7 B1              12 D5
> ;  8 B2              13 D6
> ;  9 B3              14 D7
> ; 10 B4               4 RS D/I_
> ;  5 Gnd              5 R/W_
> ; 11 B5               6 E
>
> ; Data lines from D0 to D3
> #DEFINE   LCD_RS    PORTB,    4
> #DEFINE   LCD_EN    PORTB,    5
> #DEFINE   LCD_LINE2 0x40
>
> SENDCMD:
>           BCF       LCD_RS              ; RS=0 (command)
>           CALL      SEND                ; Send the command
>           CALL      SHORTDELAY          ; A short delay
>           RETURN                        ; Return
>
> PUTLCD:
>           BSF       LCD_RS              ; RS=1 (data)
>           CALL      SEND                ; Send the data
>           CALL      SHORTDELAY          ; A short delay
>           RETURN                        ; Return
>
> SEND:
>           MOVWF     LCDTEMP2            ; Temporarily store command/data
>           SWAPF     LCDTEMP2            ; Swap nibbles
>           MOVFW     LCDTEMP2            ; Load back into W
>           ANDLW     0x0F                ; Mask off
>           IORWF     PORTB,    F         ; OR with PORTB
>           CALL      PULSE_E             ; Pulse the EN line
>
>           SWAPF     LCDTEMP2            ; Second run - lower eight bits
>           MOVFW     LCDTEMP2            ; Load back into W
>           ANDLW     0x0F                ; Mask off
>           IORWF     PORTB,    F         ; OR with PORTB
>           CALL      PULSE_E
>           RETURN                        ; Return
>
> INITLCD:
>           MOVLW     0x00                ; W=0
>           TRIS      PORTB               ; PORTB=all outputs
>           CLRF      PORTB               ; Clear PORTB
>           CLRF      LCDTEMP0            ; Clear delay counters
>           CLRF      LCDTEMP1
>
>           CALL      LONGDELAY           ; Long delay while LCD starts up
>
>           MOVLW     0x33
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x33
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x32
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x44
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x06
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x0C
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x01
>           CALL      SENDCMD             ; Send it to the LCD
>           MOVLW     0x02
>           CALL      SENDCMD             ; Send it to the LCD
>
>           CLRF      LCDTEMP0            ; Clear delay counters
>           CLRF      LCDTEMP1
>           CALL      LONGDELAY
>           RETURN
>
> LONGDELAY:
>           CALL      SHORTDELAY          ; Long delay for LCD to initialise
>           DECFSZ    LCDTEMP0, F         ; Decrement count
>           GOTO      LONGDELAY           ; Keep going
>           RETURN                        ; Return.
>
> SHORTDELAY:
>           DECFSZ    LCDTEMP1, F         ; Short delay (LCD BUSY)
>           GOTO      SHORTDELAY          ; Keep going
>           RETLW     0                   ; Return.
>
> PULSE_E:
>           BSF       LCD_EN              ; EN high
>           NOP                           ; 1uS delay
>           BCF       LCD_EN              ; EN low
>           RETLW     0
>
> MOVECRSR:                               ; Move cursor, W=address
>           ADDLW     0x80                ; Add command to W
>           CALL      SENDCMD             ; Send the command
>           CALL      SHORTDELAY          ; Short delay (LCD BUSY)
>           RETURN
> --8<--- END OF LCD-4BIT.INC
>
> --8<--- LCDTEST.ASM
>           LIST      P=16C84
>           INCLUDE   "P16C84.INC"
>  __CONFIG _XT_OSC & _PWRTE_OFF & _CP_OFF & _WDT_OFF
>
> ; Variables
> TEMP      EQU       0x16
> LCDTEMP0  EQU       0x17
> LCDTEMP1  EQU       0x18
> LCDTEMP2  EQU       0x19
>
> ; Code
>
>           ORG       0                   ; Reset vector
>           GOTO      INIT
>           ORG       4                   ; Interrupt vector
>           GOTO      INIT
>           ORG       5                   ; Start of code area
>
> ; Includes
>           ERRORLEVEL -305
>           ERRORLEVEL -302
>           INCLUDE   "LCD-4BIT.INC"
>
> ; Main code
>
> INIT:
>           MOVLW     0                   ; W=0
>           TRIS      PORTB               ; PORTB=all outputs
> MAIN:
>           CALL      INITLCD             ; Initialise the LCD
>           MOVLW     'H'
>           CALL      PUTLCD              ; Send to LCD
>           MOVLW     'e'
>           CALL      PUTLCD              ; Send to LCD
>           MOVLW     'l'
>           CALL      PUTLCD              ; Send to LCD
>           MOVLW     'l'
>           CALL      PUTLCD              ; Send to LCD
>           MOVLW     'o'
>           CALL      PUTLCD              ; Send to LCD
> CRASH:
>           GOTO      CRASH
>           END
> --8<--- END OF LCDTEST.ASM
>
> --
> Phil.
> http://www.philpem.f9.co.uk/
> philpem@bigfoot.com
>
> --
> http://www.piclist.com hint: PICList Posts must start with ONE topic:
> [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
>
>

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