Having Problem to use LCD...

Discussion in 'The Projects Forum' started by kae23, Jul 10, 2007.

  1. kae23

    Thread Starter New Member

    Jul 10, 2007
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    0
    I will be used MC68HC11 for my project.......LCD will be used and the Display for the output level...my LCD type is HD47780 manucfactured by Hitachi....

    Having problem to intialize the LCD.......so,

    I'm really glad if anybody could help me....thanks....
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Can you describe your specific problem?

    It would help if you would provide is with the code you have written to initialize the display.

    hgmjr
     
  3. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    One of the best websites I have encountered concerning LCD displays that are HD44780 based is this link.

    hgmjr
     
  4. kae23

    Thread Starter New Member

    Jul 10, 2007
    5
    0
    Thank you....I still do not intialize the LCD because do not really understand....what shold be done to Initialize....After reading the data sheet ..I still do not understand....but from the link u gave me...I will try my best to do my project...thanks again...
     
  5. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    The HD44780 device contains a number of internal registers that require setup immediately following the application of power before the display can be used. These registers contain addresses and configuration bits that determine things like in what row and in what column the next character written to the display will be placed. Other registers contain things that tell the HD44780 how to interpret the incoming data such as whether to expect the command and/or character data to be written as an 8-bit value or two consecutive 4-bit values. There are others registers that you can read about by accessing a copy of the data sheet for the HD44780 device.

    All of these registers are latches and thus their contents are not predictable over power down and power up cycles. For this reason, an initialization of these registers must be performed shortly following power-up.

    You should be able to study the example code for several microcontrollers that are provided at the link from my previous post and get a good idea of how to structure your code to perform the required initialization.

    Feel free to post your code here so that the members can assist as you work through any problems you encounter in developing your initialization code.

    hgmjr
     
  6. kae23

    Thread Starter New Member

    Jul 10, 2007
    5
    0
    I'm using Port A and Port B for my LCD. the connections to the LCD are:

    RS = PA4
    R/W = PA3
    E = PA5

    DB7 = PB7
    DB6 = PB6
    DB5 = PB5
    DB4 = PB4
    DB3 = PB3
    DB2 = PB2
    DB1 = PB1
    DB0 = PB0

    This is my initialization instructions for my LCD....but the still don't know this is correct or not....because nothing happened after downloading the instruction to my board....

    PORTA EQU $1000
    PORTB EQU 4
    PACTL EQU 26

    ORG $B600

    LDS #$FF
    LDX #PORTA
    LDAA $80
    STAA PACTL
    START
    LDAA #%00000000
    STAA 0,X
    BSR INI_LCD
    BSR DISP
    BRA START

    INI_LCD

    LDAA #$38 ;FUNCTION SET
    STAA 4,X
    LDY #5
    BSR DELAY
    LDAA #$38
    STAA 4,X
    LDY #5
    BSR DELAY
    LDAA #$38
    STAA 4,X
    LDY #5
    BSR DELAY
    LDAA #$38 ;FUNCTION SET
    STAA 4,X
    LDY #5
    BSR DELAY
    LDAA #$06 ;ENTRY MODE
    STAA 4,X
    LDY #5
    BSR DELAY
    LDAA #$0E ;DISPLAY ON/OFF
    STAA 4,X
    LDY #5
    BSR DELAY
    LDAA #$01 ;DISPLAY CLEAR
    STAA 4,X
    LDY #233
    BSR DELAY
    LDAA #$80 ;SET DDRAM ADDRESS (1 LINE)
    STAA 4,X
    LDY #5
    BSR DELAY
    RTS

    DISP
    BSET 0,X %00010000
    BSR ESTROBE
    LDAA DATA
    STAA 4,X
    BSR ESTROBE
    RTS

    ESTROBE
    BSET 0,X %00100000
    BCLR 0,X %00100000
    LDY #5
    BSR DELAY
    RTS

    DELAY
    DEY
    BNE DELAY
    RTS

    ORG $B700

    DATA

    FCC 'kae23'

    ORG $E000
    FCB $7E,$B6,$0

    END


    hopefully....someone will help me to overcome this problem......
     
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