All I can display is garbage on my LK204-25-PC rev1.2

brannfenix · Post by **brannfenix** » Tue Aug 15, 2006 1:50 pm

Hi!

I ended up buying a LK204-25-PC rev1.2 a few years back for my case mod and was very pleased with it. After ditching the case it was build into ages ago I stopped using this nifty little LCD until today when I wanted to put it to work on a new project.

Now, I am a bit rusty since its been awhile. I read over the manual a few times and downloaded uProject after reading about it on this forum. I connected everything per the manual's instructions including adding a jumper to keypad pin 5 and 6 to give the LCD a test at 19200 baud. It connects, but sadly every time I send text to print on the screen it gives me some random garbage characters. If I change the baudrate it displays different garbage chars for the same text I try to display every time(123 or abc). Also, if I make any changes to the settings like backlight for example it does not work an only outputs more garbage.

Please let me know if there is anything I might be missing here. I would really love to get this great LCD working again.

Thanks in advance,
Brann

Jon · Post by **Jon** » Tue Aug 15, 2006 2:23 pm

Hi Brann,

Would it be possible for you to post a picture of the back of the display module? This will help us trouble shoot this problem more effectively.

--
Jon

brannfenix · Post by **brannfenix** » Tue Aug 15, 2006 3:44 pm

Thanks for the speedy reply! I have attached 2 images that I hope will help. One is the back of the display that you asked for and please let me know if you need any names or numbers from chips that are unclear. the other is the a shot of what gets displayed when I try to output "123" on my com2 port at 19200 baud with the jumpers on pin 5 and 6... well it will display this with the jumper off as well.

Please let me know if there is anymore info that might help. I would really like to get this lcd up and running again

Thanks again,
Brann

LCD OUTPUT PIC: http://www.brannfenix.com/123OutPut.jpg
BACK OF DISPLAY: http://www.brannfenix.com/BackofLK204_25_PC.jpg

brannfenix · Post by **brannfenix** » Tue Aug 15, 2006 8:51 pm

Ok....

So, round one I found out I am just stupid

If anyone looks at the pic I posted of the back panel on the LCD you can see that I have the TTL pads connected and not the RS232 pads that I thought I did. So, duh me for trying to use uproject at 19200 baud in TTL mode since that sure could be a problem...

I noticed this and after slapping myself in the head I switched to the correct mode and fired up uproject to find it working 100% fine. What a shocker... if you connect it the correct way it works

Anyways, after I got the LCD talking to my PC I then started to follow the steps outlines in this thread:
http://www.lcdforums.com/forums/viewtopic.php?t=937

First I set the lcd to 9600 baud then disconnect uproject and reconnected at 9600 without any problems. I then fixed the pads back to TTL mode followed by hooking up some jumper wired to the pins 2,3, and 5 then running the sample code from the thread. When I fired up the BASIC Stamp 2 all I got was garbage on the screen. I took my multimeter and tested all the pads to make sure I did not short anything or have a bad joint. I am now scratching my head yet again

I'm in TTL mode with pad 2 and 4 connected and I used uproject to set the LCD at 9600 baud. What am I doing wrong this time?

*****UPDATE*****

OK! It seems the problem is every time I cut the power to the LCD the baud rate resets to 19200 which is making me crazy. I followed the instructions here http://www.lcdforums.com/forums/viewtop ... 7121#17121 and used the upload raw data function which seemed to work... but as soon as I cut the power it was back to 19200

Is there a different way I need to go about changing the default rate since my LCD is older? I am so close I can taste it and would really like to get this working heh

Thanks,
Brann

Paradigm · Post by **Paradigm** » Wed Aug 16, 2006 11:57 am

Wow, it's been a while since I've seen one of those

I hate to admit it, but I think the PC version had a bug that didn't save the baud rate

If I'm right, I think you have only two options, to run at 19,200 (the easier) or to change the baud rate to 9600 while talking 19200 and then drop to 9600 every time you power it up (the more difficult option)

brannfenix · Post by **brannfenix** » Wed Aug 16, 2006 12:46 pm

Wow indeed

Talking at 19200 seems to be my only option. I tested it out and was able to talk to the LCD via the BASIC Stamp 2 at that rate, but I had a problem where it would display a solid block character every second or so until the display was full of them. I am talking to people on the BS2 side to see if it is something I am doing there, but I am just wondering if maybe I am dealing with another bug? Also, are there any other known bugs with the PC version I should know about that could save me a day of pulling my hair out some other time? I guess in the end I would rather it be a bug than me doing something wrong or being 100% insane.. heh

Paradigm · Post by **Paradigm** » Wed Aug 16, 2006 3:17 pm

I can understand your frustration. To my knowledge that was the only known bug in the PC that I could find for the revision 1.2, although it has been a long time since we have discontinued that product.

brannfenix · Post by **brannfenix** » Thu Aug 17, 2006 12:38 am

Paradigm, I did not mean to sound rude or anything with my last post and it seems now that I know it is a bug I found a nice easy work around in my BASIC Stamp 2 code. Everything is fine baud rate wise as far as I can tell, but I having another problem with a weird character on the screen and I hope you guys can give me some info as to what it is and maybe what the ASCII code is to print it or something to allow me to maybe filter the character somehow.

Here goes:

I have the LCD baud rate stuff all figured out and I am not having problems sending commands anymore which is awesome. The only problem I'm still having is that goofy character that keeps getting printed to the LCD. Here is some updated info on it and a picture of what it looks like in action, I really hope someone out there has some ideas how I can either fix or at least cancel the stupid things out as they are printed to the display.

Here are my new findings:

1. It seems the characters are not really basic sqaures or blocks as I first thought. I have attached a picture of the character in question to this post. Maybe the first step to fixing out how to get rid of it is to figure out wtf it is...

2. The LCD outputs these characters one at a time in a neat little row until the first line is full then it just moves on to the second line and seems to loop forever.

3. I did not take a stopwatch to it, but it seems to output on of these characters every 3ish seconds or so.

4. This problem only happens when I am hooked up to the BS2 in TTL mode no matter what the baud rate is. When I change it back to RS232 mode and hook it up to my computer everything is 100% fine.

Please let me know anything anyone can think of since I am pretty stuck on this one

Thanks in advance,
Brann

brannfenix · Post by **brannfenix** » Thu Aug 17, 2006 10:05 am

***************PROBLEM SOLVED***************

I found the fix to this little problem on the Parallax forums. Turns out it was a simple problem with the way my code ended. So I was using this

Code: Select all

SEROUT 1, 32, [254, 88]
SEROUT 1, 32, ["TEST" ]
END

The above code gave me the stupid character and this code fixed it:

Code: Select all

SEROUT 1, 32, [254, 88]
SEROUT 1, 32, ["TEST" ]
Finish:
GOTO Finish

I am still looking in why this fixes it, but it seems after you output to the LCD you loop the the code to do nothing.

I hope this helps anyone that has this problem in the future

-Brann

Paradigm · Post by **Paradigm** » Thu Aug 17, 2006 10:09 am

--- Edited as we posted at the same time ---

Excellent.

Glad to hear that everything is up and running. Sorry if I was short on the fourms before. I was just very busy at the time, but I still wanted to at least take the time to reply.

BTW post some pictures of the final result in the gallery and let us know what you're doing with our displays.

brannfenix · Post by **brannfenix** » Thu Aug 17, 2006 10:17 am

No problem

I am using it in a project that will control the water temps, quality, ect of a fish tank and I'll be sure to post pics and stuff when its finished

Levell0rd · Post by **Levell0rd** » Tue Nov 07, 2006 8:24 am

brannfenix wrote:No problem

I am using it in a project that will control the water temps, quality, ect of a fish tank and I'll be sure to post pics and stuff when its finished

What can I use to monitor the temps of water? I don't quite get it. I didn't think I could put the temp probe in water? It is going to be inside of a computer reservoir so it should be non-conductive fluid, but still.

Jon · Post by **Jon** » Tue Nov 07, 2006 2:39 pm

Levell0rd wrote:
brannfenix wrote:No problem

I am using it in a project that will control the water temps, quality, ect of a fish tank and I'll be sure to post pics and stuff when its finished
What can I use to monitor the temps of water? I don't quite get it. I didn't think I could put the temp probe in water? It is going to be inside of a computer reservoir so it should be non-conductive fluid, but still.

Well here's a little trick, place some epoxy on the end of the temp probe to seal it and presto, water proof.

--
Jon