Parallax LCD Display #27977 not working ...

OLIE

Dear staff @ Parallax
Dear Basic-Stamp enthusiast

I purchased a Display #27977 from a local retailer.

I have some experience with Parallax products, but this is actually my first time that I connected a LCD.
Apparantly, and according to the user's documentation, connection should be quite easy to do: you connect Vdd (5V) and Vss (ground). So, this was done and also the test display worked and came on ("Parallax" appears, and the backlight is on). So far, so good.

But then you have to attach the wire from the "RX"-pin of the LCD to some of the 16 pins of the basic stamp
(lets say pin 0) and select the proper baud-rate (let's say 19'200) and set the dip-switch accordingly. I did that too.

What I had then, was the cursor waiting at the first position of the display. Still: so far so good.

But then when I entered the following sample code and tried to run this software, the cursor just stays in position and it doesn't write ! Despite the connection being ok, the cable downloads the software to the
stamp, my computer monitor-screen debugs "TEST", but there is no writing on the LCD ! Nothing at all happens, I also tried to activate the backlight with a command.

Can you help ? Is the LCD damaged and shall I get a new one from the Parallax-distributor ?

Here is the sample code from the manual:

'{$STAMP BS2}

Debug "TEST"

TxPin CON 0

Baud19200 CON 32

HIGH TxPin

PAUSE 100

SEROUT TxPin, Baud19200, [noparse][[/noparse]"Hello, this text will wrap."]

End



Thanks·a lot for your support

OLIE























·

Jon Williams

Did you cycle power after you changed the DIP switch?· You need to do that so that the LCD gets initialized properly (it only checks the switches on power-up).· Also, try to run our demo code so that you don't accidentally introduce any coding errors -- our code is usually pretty easy to modify once you get it working.

You can download code here: http://www.parallax.com/detail.asp?product_id=27976

Also: What BASIC Stamp module are you using?· The baud rate constant you're using is for the BS2/BS2e/BS2pe -- if you're using a BS2sx, BS2p, or BS2px then it won't work.· The best way to prevent this problem is to use conditional compilation to set the baudmode values for SERIN and SEROUT.· Here's a snippet from the Serial LCD template I have on my PC (also attached).

#SELECT $STAMP
· #CASE BS2, BS2E, BS2PE
··· T2400······ CON···· 396
··· T9600······ CON···· 84
··· T19K2······ CON···· 32
· #CASE BS2SX, BS2P
··· T2400······ CON···· 1021
··· T9600······ CON···· 240
··· T19K2······ CON···· 110
· #CASE BS2PX
··· T2400······ CON···· 1646
··· T9600······ CON···· 396
··· T19K2······ CON···· 188
#ENDSELECT

LcdBaud········ CON···· T19K2

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Jon Williams
Applications Engineer, Parallax

Post Edited (Jon Williams (Parallax)) : 1/1/2006 4:35:49 PM GMT

Newzed

Download the sample codes for this device from the Parallax site and run them.· Then check the Parallax code against your code.

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Sid Weaver
Do you have a Stamp Tester yet?
http://hometown.aol.com/newzed/index.html

·

OLIE

Dear Sirs

First of all, thanks a lot for your answers and support. But unfortunately (and a bit disappointing), it doesn't really seem to work ...

I got a basic stamp2 (BS2, version 1.0).


There is a very simple code in the manual I downloaded:

'{$STAMP BS2}

SEROUT 1, 84, [noparse][[/noparse]22, 12]
PAUSE 5

SEROUT 1, 84, [noparse][[/noparse]"See this?", 13,·"The LCD works!"]

End


For a change, I connected RX-line to Pin 1, so this should be correct. Also, I changed the dip-switch accordingly (9600 baud-rate is switch 1 off, switch 2 on).

Always, before I change anything, of course I disconnect power to prevent any damage of any part.
The cursor just stays in place, no writing, no movement ...

Any other ideas are very welcome, otherwise I guess I have to send it back to Parallax· ;-)

Best regards


OLIE




·

Bruce Bates

Olie -

Change the very beginning of your program to read like this:

'{$STAMP BS2}
DEBUG "Running"

If "Running" does not appear on your PC monitor, the program is not executing at all. If that's the case, we'll deal with it from there.

Regards,

Bruce Bates

OLIE

Dear Bruce

It does appear, indeed (I mean on the PC-monitor).

There doesn't seem to be a problem with the stamp nor with the Basic Stamp Super Carrier Board.
A connection is there (Loopback: "yes", Echo: "yes").

Regards and thanks

Olie

Post Edited (OLIE) : 1/1/2006 6:29:26 PM GMT

Chris Savage

Olie,

·· Contact Tech Support Monday to get an RMA number for your LCD.· Have everything set up though so we can rule out anything else.· Take care.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

T&E Engineer

Can this information be updated in to the LCD datasheets for the BS2px:

#SELECT $STAMP
· #CASE BS2, BS2E, BS2PE
··· T2400······ CON···· 396
··· T9600······ CON···· 84
··· T19K2······ CON···· 32
· #CASE BS2SX, BS2P
··· T2400······ CON···· 1021
··· T9600······ CON···· 240
··· T19K2······ CON···· 110
· #CASE BS2PX
··· T2400······ CON···· 1646
··· T9600······ CON···· 396
··· T19K2······ CON···· 188
#ENDSELECT

LcdBaud········ CON···· T19K2


I needed to use the BS2px with a Serial LCD and it had a problem with "LcdBaud" statement because the current documentation does not have anything listed for the BS2px that I could find. I did a search on the forum to find this info. It would be more useful to have this updated in the documentation on the Parallax website.

Thanks,

Timothy Gilmore