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Re: LCD screens from Computer Recyclers

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  • stephane.gauthier@alcatel.com
    Thanks, I will try this. btw, your lcd3.asm attachment comes out as a 1 byte file. Could you post it again? Thanks Take care, ... get the ... will ... a ...
    Message 1 of 4 , Apr 1, 2001
    • 0 Attachment
      Thanks, I will try this.

      btw, your lcd3.asm attachment comes out as a 1 byte file. Could you
      post it again? Thanks

      Take care,

      --- In ORE_bits@y..., "galapagos" <galapagos@h...> wrote:
      > I played arround with a lot of LCD displays and I know that the
      > initialization timing has to be almost perfect
      > else you will have nothing but headaches.
      >
      > You mentioned that you tried using the dip switch setup to manually
      get the
      > display to work
      > just make sure that the enable line is clean and debounced else it
      will
      > latch data multiple times and it will not work. At Algonquin we had
      a
      > similar setup with switches and I remeber to this day that the
      enable line
      > was fed
      > in a flip flop for debounce.
      >
      > I did manage to get the displays to work in both 4 bit and 8 bit
      mode.
      >
      > I attached a sample initialization assembly program i wrote that
      worked for
      > me.
      > feel free to modify as wanted. I also have the hex file but you will
      > probably have to modify the include for the 16F877
      >
      > The program assumes that u are using the LCD in 4 bit mode with a
      16F84 PIC,
      > it is documented with lots of comments and it displays Hello on
      the LCD
      > as a test.
      >
      > And make sure that your LCD contrast pin is connected to ground or
      you may
      > not see much on the LCD
      > some industrial LCD desigend for a wide temperature ranges might
      even
      > require a negative voltage the contarst pin. ( i had one of thes and
      I
      > thought that it was broken but if I looked at it from a low angle
      you could
      > see the text but barely.) keep that in mind.
      >
      >
      > Have Fun
      >
      > Laz
      >
      >
      >
      > ----- Original Message -----
      > From: <stephane.gauthier@a...>
      > To: <ORE_bits@y...>
      > Sent: Friday, March 30, 2001 11:55 PM
      > Subject: [ORE_bits] LCD screens from Computer Recyclers
      >
      >
      > > Hi,
      > >
      > > I recently bought two 24x2 LCD screens from Computer Recyclers and
      > > I just can't get them to work.
      > >
      > > They use the standard Hitachi HD44780 LCD Controller Chip with two
      > > Sanyo LC7930 LCD interface chips.
      > >
      > > The PCB and module is made by Optrex and is marked as PWB
      24227-CEM.
      > > The official Optrex model number is apparently DMC-24227. I
      verified
      > > that to be true and I got the data-sheets for it.
      > >
      > > I've tried the 4 bit technique with shift-register then got fed up
      > > with the complexity and tried the 8 bit technique to eliminate any
      > > potential timing issues. Still doesn't work. I even tried the
      > > suggested dip switches setup and I still can't even get the LCD to
      > > show a simple pixel or anything!!
      > >
      > > Help would be appreciated from anybody with LCD experience,
      > >
      > > Thanks in advance,
      > >
      > >
      > >
      > > To unsubscribe from this group, send an email to:
      > > ORE_bits-unsubscribe@egroups.com
      > >
      > >
      > >
      > > Your use of Yahoo! Groups is subject to
      http://docs.yahoo.com/info/terms/
      > >
      > >
      > >
    • galapagos
      ... From: To: Sent: Sunday, April 01, 2001 2:45 PM Subject: [ORE_bits] Re: LCD screens from Computer
      Message 2 of 4 , Apr 2, 2001
      • 0 Attachment
        ----- Original Message -----
        From: <stephane.gauthier@...>
        To: <ORE_bits@yahoogroups.com>
        Sent: Sunday, April 01, 2001 2:45 PM
        Subject: [ORE_bits] Re: LCD screens from Computer Recyclers


        > Thanks, I will try this.
        >
        > btw, your lcd3.asm attachment comes out as a 1 byte file. Could you
        > post it again? Thanks
        >
        > Take care,
        >
        > --- In ORE_bits@y..., "galapagos" <galapagos@h...> wrote:
        > > I played arround with a lot of LCD displays and I know that the
        > > initialization timing has to be almost perfect
        > > else you will have nothing but headaches.
        > >
        > > You mentioned that you tried using the dip switch setup to manually
        > get the
        > > display to work
        > > just make sure that the enable line is clean and debounced else it
        > will
        > > latch data multiple times and it will not work. At Algonquin we had
        > a
        > > similar setup with switches and I remeber to this day that the
        > enable line
        > > was fed
        > > in a flip flop for debounce.
        > >
        > > I did manage to get the displays to work in both 4 bit and 8 bit
        > mode.
        > >
        > > I attached a sample initialization assembly program i wrote that
        > worked for
        > > me.
        > > feel free to modify as wanted. I also have the hex file but you will
        > > probably have to modify the include for the 16F877
        > >
        > > The program assumes that u are using the LCD in 4 bit mode with a
        > 16F84 PIC,
        > > it is documented with lots of comments and it displays Hello on
        > the LCD
        > > as a test.
        > >
        > > And make sure that your LCD contrast pin is connected to ground or
        > you may
        > > not see much on the LCD
        > > some industrial LCD desigend for a wide temperature ranges might
        > even
        > > require a negative voltage the contarst pin. ( i had one of thes and
        > I
        > > thought that it was broken but if I looked at it from a low angle
        > you could
        > > see the text but barely.) keep that in mind.
        > >
        > >
        > > Have Fun
        > >
        > > Laz
        > >
        > >
        > >
        > > ----- Original Message -----
        > > From: <stephane.gauthier@a...>
        > > To: <ORE_bits@y...>
        > > Sent: Friday, March 30, 2001 11:55 PM
        > > Subject: [ORE_bits] LCD screens from Computer Recyclers
        > >
        > >
        > > > Hi,
        > > >
        > > > I recently bought two 24x2 LCD screens from Computer Recyclers and
        > > > I just can't get them to work.
        > > >
        > > > They use the standard Hitachi HD44780 LCD Controller Chip with two
        > > > Sanyo LC7930 LCD interface chips.
        > > >
        > > > The PCB and module is made by Optrex and is marked as PWB
        > 24227-CEM.
        > > > The official Optrex model number is apparently DMC-24227. I
        > verified
        > > > that to be true and I got the data-sheets for it.
        > > >
        > > > I've tried the 4 bit technique with shift-register then got fed up
        > > > with the complexity and tried the 8 bit technique to eliminate any
        > > > potential timing issues. Still doesn't work. I even tried the
        > > > suggested dip switches setup and I still can't even get the LCD to
        > > > show a simple pixel or anything!!
        > > >
        > > > Help would be appreciated from anybody with LCD experience,
        > > >
        > > > Thanks in advance,
        > > >
        > > >
        > > >
        > > > To unsubscribe from this group, send an email to:
        > > > ORE_bits-unsubscribe@egroups.com
        > > >
        > > >
        > > >
        > > > Your use of Yahoo! Groups is subject to
        > http://docs.yahoo.com/info/terms/
        > > >
        > > >
        > > >
        >
        >
        >
        > To unsubscribe from this group, send an email to:
        > ORE_bits-unsubscribe@egroups.com
        >
        >
        >
        > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
        >
        >
        >
        >
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