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Cant get my serial LCD to work — Parallax Forums

Cant get my serial LCD to work

Spoolin'JimSpoolin'Jim Posts: 9
edited 2010-10-17 06:43 in BASIC Stamp
Hello all!

Just got my first personal basic stamp2 the other day and decided to get a lcd display for my projects. The best price I found was for one just like this:

http://www.emartee.com/product/41872/Arduino-Serial-LCD-1602-Shield

I know its is for a arduino and not a basic stamp, but it should work right?

I have tried everything I can think to try and have not gotten a thing to display on it. And yes, I have used a LCD and a basic stamp before, but just cant get this one working.

Does anyone have any insight as to why this one doesn't work?

I contacted the seller and they aren't replying yet.

Thanks,
James

Comments

  • FranklinFranklin Posts: 4,747
    edited 2010-10-03 15:18
    Start by showing your code and how you have this connected to your stamp.
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-03 17:19
    I have the red wire from the display to +5v and the black to ground. I have tried both the yellow and the white wires to pin 1.

    I have tried several code segments I've found while googleing on it, but something like this I think should work. I've also tried several baud rates, but I know its 9600 from the listing, just not sure what parity (tried all choices).

    serout 1,84, [tried everything from 0-100 trying to start and clear and stuff]
    pause 10
    serout 1,84, ["Test",cr]

    Note, I don't have pbasic on this computer so thats from memory but I've tried a dozen different things all with exactly the same result, nothing...
  • Mike GreenMike Green Posts: 23,101
    edited 2010-10-03 18:06
    From the advertisement it looks like the display requires a command that starts with $ like $PRINT and ends with a carriage return (CR). Try the "Hello World" example shown in the advertisement except using SEROUT 1,84,[""] instead of the corresponding Arduino serial output statement.
  • FranklinFranklin Posts: 4,747
    edited 2010-10-03 19:18
    Here is the schematic http://www.emartee.com/Attachment.php?name=41872.pdf Post your actual code and how you have it hooked up.
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-04 13:42
    My LCD is hooked up red to Vdd, black to Vss, Yellow to pin1. Here is the code taken from the add adapted to the stamp.


    ' {$STAMP BS2}
    ' {$PBASIC 2.5}

    x CON 84 'baud rate

    DO
    SEROUT 1,x,["$CLEAR",CR]
    SEROUT 1,x,["$GO 1 1",CR]
    SEROUT 1,x,["$PRINT Flamingo**EDA",CR]
    SEROUT 1,x,["$GO 2 4",CR]
    SEROUT 1,x,["$PRINT Hello World!",CR]
    SEROUT 1,x,["$CURSOR 1 1",CR]
    LOOP

    When I run this code, I get nothing. I tried the different 9600 baud settings and both the yellow and the white wires.
  • FranklinFranklin Posts: 4,747
    edited 2010-10-04 14:13
    In Arduino code Serial.print does not add a CR. That is done with a Serial.println command. You might try removing the CRs. Also the white and yellow are rx and tx, perhaps they both need to be connected. Next time think about buying Parallax products and you wouldn't have this much trouble :lol:
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-04 14:38
    I would have bought Parallex if it was cheaper :P

    I took the ,cr out and it still does nothing.

    edit:
    How do I hook the receive line up also? Just run it to ground?
  • AmaralAmaral Posts: 176
    edited 2010-10-04 15:54
    Have you tried inverted polarity ?

    try: x CON 16484 'baud rate



    Amaral
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-04 16:55
    Do you mean 16468? And yes, as I've stated, I have tried nearly all baud rates available to the basic stamp 2.
  • rixterrixter Posts: 95
    edited 2010-10-04 19:35
    Have you tried ajusting the contrast? Perhaps something you doing is actually working and you just can't see it.

    Rick
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-05 06:55
    Yes, I have adjusted the contrast and backlight several times. I'm begining to think the display is just bad maybe.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-10-05 16:11
    I don't see wire colors on the 'schematic' and I can't see in the photos well enough to read the pcb's silkscreen. Have you tried connecting your SEROUT pin to the unit's white wire, instead of the yellow, just for GPs? I don't know what arduino's convention is ('tx to tx' or 'tx to rx'?) and I advise a 100_ohm resistor till you know what's what, won't hurt too much to try.
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-05 16:21
    I know people are trying to help, but please read what I've said before telling me to try something. Yes, I have tried both wires, I have tried both wires with one grounded through a 1k resistor, I've even tried no wires :lol:
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-10-05 17:27
    With only power connected (RX and TX disconnected) does the arduino unit have +5 on its RX or TX pins?
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-06 03:27
    Just used my meter to check and there is +5v on the white (transmit) line with just the stamp powered up but no signal going to it.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-10-06 10:00
    OK, so the white wire must be a transmit line from the arduino unit, equiv. Parallax TTL-True (XMTR idle state = +5), so I'd figure that it expects data in that format, too.

    The "emartee" page constitutes the documentation for the unit?
    It states that comms to the arduino unit begin with "$" and end with "rn" (romeo november), but I don't see any "rn" in the example instructions.

    Oh, well; save a little, spend a lot. Maybe emartee will get back to you.
  • dadamsadadamsa Posts: 6
    edited 2010-10-06 20:56
    I'm new on this forum but have been working with stamps for a while.

    Since you are new to working with the Basic Stamps, try a known to work project and then experiment. The LCD appears to be a standard 16x2 Parallel type LCD. If the Arduino serial adapter can be unplugged, try running the LCD in 4-bit parallel mode. Parallax has code on their website that will get you going and then you can start experimenting from there.

    At least you can confirm that the LCD works.

    It's always good to start with a well documented project.

    Parallax also does have code for their serial LCDs as well but I don't know if they are compatible with the Arduino adapter.

    Also, here is a link to an eBay seller's listing for a good 16x2 LCD for $4 bucks and a buck fifty for shipping. He has a link to code that I know works (I sent him the code along with a drawing for the connections) for a 16x2 LCD running in 4-bit parallel mode. He's a good seller and ships quickly.

    http://cgi.ebay.com/16-x-2-Basic-Stamp-LCD-DISPLAY-MODULE-W-BACKLIGHT-/120626844780?pt=LH_DefaultDomain_0&hash=item1c15eb946c

    Hope this helps,
    Doug
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-10-14 19:20
    Parallax's Serial LCD, for which you can get abundant support, right here, is on sale today: $21.
    [Hoping the OP sees this in time to take advantage.]

    http://www.parallax.com/Store/Accessories/Displays/tabid/159/ProductID/50/List/0/Default.aspx?SortField=ProductName,ProductName
  • $WMc%$WMc% Posts: 1,884
    edited 2010-10-15 17:58
    Spoolin'Jim wrote: »
    I know people are trying to help, but please read what I've said before telling me to try something. Yes, I have tried both wires, I have tried both wires with one grounded through a 1k resistor, I've even tried no wires :lol:
    '
    Does your display have DIP switch settings???
  • Spoolin'JimSpoolin'Jim Posts: 9
    edited 2010-10-17 06:43
    Well, I ended up desoldering my LCD from the serial adapter board it came with and buying a serial adapter off Ebay. All is well now. Total price payed to get a working 2X16 back-light display was about $25 :smhair:. At least I can use the new adapter to drive several different kinds of displays and 4 aux outputs. My dad was kind enough to make a PC board to hold it all for me :)

    Link to new serial adapter:
    http://cgi.ebay.com/Serial-LCD-Kit-117-9600-No-LCD-PIC-Stamp-Arduino-/360258741440?pt=LH_DefaultDomain_0&hash=item53e11824c0

    What I should have gotten I guess:
    http://cgi.ebay.com/Serial-LCD-Kit-117-w-16X2-LCD-White-Backlight-/360012730163?pt=LH_DefaultDomain_0&hash=item53d26e4f33
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