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Sending data to lcd from a bs2-question. — Parallax Forums

Sending data to lcd from a bs2-question.

ArchiverArchiver Posts: 46,084
edited 2003-08-21 12:47 in General Discussion
I have a SLI-OEM rev B serial to lcd converter board by Wirtz.
I have an 8944-OP lcd.
I have a BS2 stamp.
I have tried both 2400 baud and 9600 baud.
I put a 1.5 kOhm resistor pull up on the data line as recommended by the
SLI-OEM documentation.
The lcd receives information correctly from the RS-232 line on my
computer.

I have tried several versions of programs to make the lcd repeat out my
ser-out commands. I have also used the simple ser-out program statement
in the stamp book.

All I get is gobbledegook on the lcd. However, the gobbledegook does
change when it is receiving information.

There's got to be something simple that I am missing. Question is, what
is it???

I stand by for incoming rounds<G>.

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-08-19 21:04
    If you supply your BS2 test code it will help with diagnosis. [noparse]:)[/noparse] Just
    place the code in with your question next time.

    Also, have you verified that the Serial (SLI-OEM) "backpack" is correctly
    receiving serial by sending directly to it with Hyperterm or some other
    known-good serial source? This would allow you to determine if this a
    stamp coding/interfacing problem or a backpack/lcd problem...

    Vern

    --
    Vern Graner CNE/CNA/SSE | "If the network is down, then you're
    Senior Systems Engineer | obviously incompetent so why are we
    Texas Information Services | paying you? Of course, if the network
    vern@t... www.txis.com | is up, then we obviously don't need
    Cell 507-7851 Desk 328-8947 | you, so why are we paying you?" VLG



    Grover Richardson said:
    >
    >
    > I have a SLI-OEM rev B serial to lcd converter board by Wirtz.
    > I have an 8944-OP lcd.
    > I have a BS2 stamp.
    > I have tried both 2400 baud and 9600 baud.
    > I put a 1.5 kOhm resistor pull up on the data line as recommended by the
    > SLI-OEM documentation.
    > The lcd receives information correctly from the RS-232 line on my
    > computer.
    >
    > I have tried several versions of programs to make the lcd repeat out my
    > ser-out commands. I have also used the simple ser-out program statement
    > in the stamp book.
    >
    > All I get is gobbledegook on the lcd. However, the gobbledegook does
    > change when it is receiving information.
    >
    > There's got to be something simple that I am missing. Question is, what
    > is it???
    >
    > I stand by for incoming rounds<G>.
    >
    >
    > To UNSUBSCRIBE, just send mail to:
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    > from the same email address that you subscribed. Text in the Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-08-19 21:53
    Yup, that serial LCD module sucks. I bought two and went through the
    same hell.

    I finally got mine to work at 1200 or 2400 -- nothing higher. Part of
    the problem is holding the data line in a constant state when the module
    is powered up -- provided you can switch the power on cleanly. You also
    have to delay any commands going to the module until its powered up.

    I don't have the modules here to look at, but I believe I used a pull-up
    or pull-down resistor and told the Stamp to wait 3-4 seconds before
    sending a command. At any rate, its vaguely documented in the
    instruction sheet.


    On Tue, 2003-08-19 at 14:59, Grover Richardson wrote:
    >
    > I have a SLI-OEM rev B serial to lcd converter board by Wirtz.
    > I have an 8944-OP lcd.
    > I have a BS2 stamp.
    > I have tried both 2400 baud and 9600 baud.
    > I put a 1.5 kOhm resistor pull up on the data line as recommended by the
    > SLI-OEM documentation.
    > The lcd receives information correctly from the RS-232 line on my
    > computer.
    >
    > I have tried several versions of programs to make the lcd repeat out my
    > ser-out commands. I have also used the simple ser-out program statement
    > in the stamp book.
    >
    > All I get is gobbledegook on the lcd. However, the gobbledegook does
    > change when it is receiving information.
    >
    > There's got to be something simple that I am missing. Question is, what
    > is it???
    >
    > I stand by for incoming rounds<G>.
  • ArchiverArchiver Posts: 46,084
    edited 2003-08-20 02:58

    Original Message
    From: Grover Richardson [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=PgpZliTtjaIbolQTa-2w4a0UgT_tLueYu8KmOjNL7bpoVWois_vUMSOHOyNQQjAs_PfnxodHBsy-_gMXZGOvPXMM10-BD0Yi0W3iFQ]grover.richardson@g...[/url

    The lcd receives information correctly from the RS-232 line on my
    computer.

    The computer serial port uses +12v and -12v for 1 and 0. The stamp uses +5v
    and 0v. The stamp's special serial pin does a bit of trickery to get
    computers to talk to it sensibly but serin/out on any other pin isn't going
    to work directly with an RS-232 device.

    Don't forget that serial and RS-232 is like a rectangle and a square. While
    a square is always a rectangle, a rectangle is not always a square. Serial
    just means one bit at a time. RS-232 means one bit at a time AT +12/-12.


    If your LCD works directly off a PC serial port without frying then its
    RS-232, not "just" serial. Use the Stamp's special serial pin or go through
    a level converter chip like the Max232 or similar.
  • ArchiverArchiver Posts: 46,084
    edited 2003-08-20 03:59
    The SLI-OEM module is supposed to work with both TTL and PC level RS232
    with no modifications.

    > The lcd receives information correctly from the RS-232 line on my
    > computer.
    >
    > The computer serial port uses +12v and -12v for 1 and 0. The stamp uses +5v
    > and 0v. The stamp's special serial pin does a bit of trickery to get
    > computers to talk to it sensibly but serin/out on any other pin isn't going
    > to work directly with an RS-232 device.
    >
    > Don't forget that serial and RS-232 is like a rectangle and a square. While
    > a square is always a rectangle, a rectangle is not always a square. Serial
    > just means one bit at a time. RS-232 means one bit at a time AT +12/-12.
    >
    >
    > If your LCD works directly off a PC serial port without frying then its
    > RS-232, not "just" serial. Use the Stamp's special serial pin or go through
    > a level converter chip like the Max232 or similar.
  • ArchiverArchiver Posts: 46,084
    edited 2003-08-20 14:12
    Arg!! I know that, but forgot. Program below:
    **********************************
    '{$STAMP BS2}
    'set i/o pin directions
    OUTPUT 6 'SERIAL TO LCD from P6 pin

    '***** PROGRAM BELOW
    ' 2400 baud inverted and normal are 16780 396

    SEROUT 6, 16780, [noparse][[/noparse]"HELLO XXX WORLD!"]

    END

    **********************************
    Yes. I wrote a basic program to send data to it, and it works. Though
    I did note that when the input pin of the SLI unit was open (not
    connected to anything), it received nonsense. I suspect that it's a
    very high impedance and picking up room noise.

    Original Message
    From: Vernon Graner [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=a1n1UEz-1Jng3mOgXPCpvaNW0Wd0Y6FWTVygWCzD6XYOq7LSyAr31ETrJwPhWghevfcyHKALew]vern@t...[/url
    Sent: Tuesday, August 19, 2003 4:05 PM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Sending data to lcd from a bs2-question.


    If you supply your BS2 test code it will help with diagnosis. [noparse]:)[/noparse] Just
    place the code in with your question next time.

    Also, have you verified that the Serial (SLI-OEM) "backpack" is
    correctly receiving serial by sending directly to it with Hyperterm or
    some other known-good serial source? This would allow you to determine
    if this a stamp coding/interfacing problem or a backpack/lcd problem...

    Vern

    --
    Vern Graner CNE/CNA/SSE | "If the network is down, then you're
    Senior Systems Engineer | obviously incompetent so why are we
    Texas Information Services | paying you? Of course, if the network
    vern@t... www.txis.com | is up, then we obviously don't need Cell
    507-7851 Desk 328-8947 | you, so why are we paying you?" VLG



    Grover Richardson said:
    >
    >
    > I have a SLI-OEM rev B serial to lcd converter board by Wirtz. I have
    > an 8944-OP lcd. I have a BS2 stamp.
    > I have tried both 2400 baud and 9600 baud.
    > I put a 1.5 kOhm resistor pull up on the data line as recommended by
    the
    > SLI-OEM documentation.
    > The lcd receives information correctly from the RS-232 line on my
    > computer.
    >
    > I have tried several versions of programs to make the lcd repeat out
    > my ser-out commands. I have also used the simple ser-out program
    > statement in the stamp book.
    >
    > All I get is gobbledegook on the lcd. However, the gobbledegook does
    > change when it is receiving information.
    >
    > There's got to be something simple that I am missing. Question is,
    > what is it???
    >
    > I stand by for incoming rounds<G>.
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-08-21 12:47
    I haven't used a serial LCD before but I have worked with parallel's. I just
    remembered a similar sounding problem I had a while back. I was trying to
    power the LCD from an MCU pin (only uses 1.2mA total) and I kept getting
    giberish on screen. In the end it turned out that I was sending text before
    sending a cursor position (Home command). Try sending a CLS and Home to
    initialize the display before sending it text to display. Shot in the dark
    but hey, sometimes its the really simple stuff that kills us [noparse]:D[/noparse]

    Original Message
    From: Bill Boyer [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=BP15P6_tzCjAl5P5L_yfed_IUYMdCTrILo_BlBYGKTI-w0QuUSu-p6ikg5owa6FTzRsrSF_Ht3HqS9s]daweasel@s...[/url
    Sent: August 19, 2003 7:59 PM
    To: Basic Stamp List
    Subject: RE: [noparse][[/noparse]basicstamps] Sending data to lcd from a bs2-question.


    The SLI-OEM module is supposed to work with both TTL and PC level RS232
    with no modifications.

    Arg!! I know that, but forgot. Program below:
    **********************************
    '{$STAMP BS2}
    'set i/o pin directions
    OUTPUT 6 'SERIAL TO LCD from P6 pin

    '***** PROGRAM BELOW
    ' 2400 baud inverted and normal are 16780 396

    SEROUT 6, 16780, [noparse][[/noparse]"HELLO XXX WORLD!"]

    END
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