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4x 40 LCD question? — Parallax Forums

4x 40 LCD question?

ArchiverArchiver Posts: 46,084
edited 2004-05-26 04:08 in General Discussion
Hi All!

I am new to this group and working with Basic Stamps.
I don't have much experence with writing code or
working with digital electronics.
I have a 4x40 LCD I got from allelectronic.com (Optrex
DMC40457) it has two of the HD44780A00 on it. I have
only been able to write to the top two lines and the
3ed and 4th just get garbage or display nothing. Does
anybody have any code I can use to get all four lines
working?

Thanks for your help!
John Williams




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Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-05-24 16:29
    Are you initializing the display for multi-line use?

    -- Jon "No 'h' in my name" Williams
    -- Parallax

    Original Message
    From: John Williams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=VzvKh8BEDQ1cfPIHCnM48vmz2-nqdnJ8E_ZaH-YNYvfZnk-lynVIcXo9-38E75DS4DZ8UhqhYUvWy8TO]jrocco361@y...[/url
    Sent: Monday, May 24, 2004 7:23 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] 4x 40 LCD question?


    Hi All!

    I am new to this group and working with Basic Stamps.
    I don't have much experence with writing code or
    working with digital electronics.
    I have a 4x40 LCD I got from allelectronic.com (Optrex
    DMC40457) it has two of the HD44780A00 on it. I have
    only been able to write to the top two lines and the
    3ed and 4th just get garbage or display nothing. Does
    anybody have any code I can use to get all four lines
    working?

    Thanks for your help!
    John Williams




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  • ArchiverArchiver Posts: 46,084
    edited 2004-05-24 23:41
    Hi Jon!

    Sorry for the confusion about our names but ya know
    what it's like having a common name. No I did not do
    the music for Star Wars but I do wish I had his money
    [noparse]:o[/noparse])

    like I said I am new at this. All my experence has
    been in the analog world. I saw that both the upper
    two lines are $80 and $C0 but it shows that both the
    lower two lines also start with the same. I figure
    that that is normal as it uses two of the HD44780's so
    I assume that I have to address the second as the
    second or the upper is "0" and lower is "1". Do I have
    to send the info as if I am writing to two different
    displays. Enable E1 to write to the top two and enable
    E2 to write to the bottom? If you can point me in the
    right direction it would be a big help.

    Thanks for your help!
    John Williams (with the H)

    --- Jon Williams <jwilliams@p...> wrote:
    > Are you initializing the display for multi-line use?
    >
    > -- Jon "No 'h' in my name" Williams
    > -- Parallax
    >
    >
    Original Message
    > From: John Williams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=EEzoDureEJf-wDcPG9D04F-EjN2iu8s8cwis5X4L8mDkU97BRMrSi5nITXf4fpcou-UeCvnI3ItgeVUXoA]jrocco361@y...[/url
    > Sent: Monday, May 24, 2004 7:23 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] 4x 40 LCD question?
    >
    >
    > Hi All!
    >
    > I am new to this group and working with Basic
    > Stamps.
    > I don't have much experence with writing code or
    > working with digital electronics.
    > I have a 4x40 LCD I got from allelectronic.com
    > (Optrex
    > DMC40457) it has two of the HD44780A00 on it. I have
    > only been able to write to the top two lines and the
    > 3ed and 4th just get garbage or display nothing.
    > Does
    > anybody have any code I can use to get all four
    > lines
    > working?
    >
    > Thanks for your help!
    > John Williams
    >
    >
    >
    >
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Domains - Claim yours for only $14.70/year
    > http://smallbusiness.promotions.yahoo.com/offer
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed.
    > Text in the Subject
    > and Body of the message will be ignored.
    >
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    >
    >
    >
    >
    >
    >
    >
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  • ArchiverArchiver Posts: 46,084
    edited 2004-05-25 00:23
    If you have a display with two enable lines then yes, you'll have to
    write to the upper and lower halves separately (hassle). This also
    means that each half needs to be initialized. It's not tough, it just
    requires a lot of redundant code.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: John Williams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=8qTB7ww6G7r1uFDv95QPpltU1lttcyY_FiVri8dkUennFfq__ZnhvczR4qczjIVL3-yknfa9n1WT]jrocco361@y...[/url
    Sent: Monday, May 24, 2004 5:42 PM
    To: basicstamps@yahoogroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] 4x 40 LCD question?


    Hi Jon!

    Sorry for the confusion about our names but ya know
    what it's like having a common name. No I did not do
    the music for Star Wars but I do wish I had his money
    [noparse]:o[/noparse])

    like I said I am new at this. All my experence has
    been in the analog world. I saw that both the upper
    two lines are $80 and $C0 but it shows that both the
    lower two lines also start with the same. I figure
    that that is normal as it uses two of the HD44780's so
    I assume that I have to address the second as the
    second or the upper is "0" and lower is "1". Do I have
    to send the info as if I am writing to two different
    displays. Enable E1 to write to the top two and enable
    E2 to write to the bottom? If you can point me in the
    right direction it would be a big help.

    Thanks for your help!
    John Williams (with the H)

    --- Jon Williams <jwilliams@p...> wrote:
    > Are you initializing the display for multi-line use?
    >
    > -- Jon "No 'h' in my name" Williams
    > -- Parallax
    >
    >
    Original Message
    > From: John Williams [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=8qTB7ww6G7r1uFDv95QPpltU1lttcyY_FiVri8dkUennFfq__ZnhvczR4qczjIVL3-yknfa9n1WT]jrocco361@y...[/url
    > Sent: Monday, May 24, 2004 7:23 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] 4x 40 LCD question?
    >
    >
    > Hi All!
    >
    > I am new to this group and working with Basic
    > Stamps.
    > I don't have much experence with writing code or
    > working with digital electronics.
    > I have a 4x40 LCD I got from allelectronic.com
    > (Optrex
    > DMC40457) it has two of the HD44780A00 on it. I have
    > only been able to write to the top two lines and the
    > 3ed and 4th just get garbage or display nothing.
    > Does
    > anybody have any code I can use to get all four
    > lines
    > working?
    >
    > Thanks for your help!
    > John Williams
    >
    >
    >
    >
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Domains - Claim yours for only $14.70/year
    > http://smallbusiness.promotions.yahoo.com/offer
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed.
    > Text in the Subject
    > and Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
    >
    > This message has been scanned by WebShield. Please
    > report SPAM to
    > abuse@p....
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed.
    > Text in the Subject and Body of the message will be
    > ignored.
    >
    > Yahoo! Groups Links
    >
    >
    > basicstamps-unsubscribe@yahoogroups.com
    >
    >
    >





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  • ArchiverArchiver Posts: 46,084
    edited 2004-05-26 04:08
    --- In basicstamps@yahoogroups.com, John Williams <jrocco361@y...>
    wrote:
    > Hi All!
    > I have a 4x40 LCD I got from allelectronic.com (Optrex
    > DMC40457) it has two of the HD44780A00 on it. I have
    > only been able to write to the top two lines and the
    > 3ed and 4th just get garbage or display nothing. Does
    > anybody have any code I can use to get all four lines
    > working?
    > Thanks for your help!
    > John Williams

    Another John (Jon?) Williams...Hmmm, this is bound to cause some
    confusion. ;-) To answer your question; 4 X 40 LCDs have 2 Enable
    lines, and they must be strobed for each half of the display you
    wish to write to. Each half works exactly as the other, with the
    exception of needing separate Enable lines (Thus an extra pin from
    the BS2).

    What we need is a Serial Backpack chip that supports 4 X 40 line
    displays.

    Chris Savage
    Knight Designs
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