Character LCD

I found a box of over 400 but have no idea how to use them.
Datasheet: http://www.lcdsystems.com/dynamicdata/data/files/20101.PDF

That is all the info I have on them. I don't understand what the address codes are. Do I send that byte and then a character? Do I add that to what I'm sending?

I've been looking over serial tutorials and trying different things and I'm not sure what I'm doing wrong. Since I don't even know the baud rate I just want to make sure I'm not wasting my time trying a way that'll never work.

That is all the info I have on them.

You are going to need more information. This is probably a standard character mode LCD with a built in serial interface. You will need information about that interface since there are no standards.

I don't understand what the address codes are.

The addresses for the 20 characters run from 00h through 13h. The instruction to set the address for the next character consists of the address with the high bit set. This means that the instructions to set the addresses will run from 80h through 93h. This is what they are calling the 'Address Code'. A poor technique in my opinion.

Since I don't even know the baud rate...

Unfortunately you not only do not know the baud rate, you do not know what information to send either.

Do I send that byte and then a character?

Maybe

Do I add that to what I'm sending?

Maybe

Don

try to contact these guys...

They are sold here, contact the sales dept.
http://www.lcdsystems.com/index.asp?pgid=14

try to contact these guys…

I suspect that he already did - except he gave them more information.

Don

Azdle:

Looking at the photo of the back of the pc board (in the avrfreaks thread) I see a PIC processor which must be the serial interface. Peter Anderson uses these in his implementation so I suggest you start by looking here http://www.phanderson.com/lcd106/lcd107.html and using the commands for his chip.

Don

I suspect that he already did - except he gave them more information.

Ya, that's my thread over there. I thought I had added a reply here with more info, guess I didn't hit submit or something.

I have sent off an email, but I haven't heard anything (yet, hopefully).

Thanks for the link, however I don't think that's the implementation it's using. Or at least I have bigger problems. When I send any of the commands off that website, it just blanks the screen and displays the letters of the command.

I've been playing around with the baud rates and 19200 is the only baud rate that has come close to working.

I get this: http://imgur.com/rONtv.jpg The characters with the blue dash work, the others clear the screen. For some reason if the capital works the lower case doesn't and if the capital doesn't the lower case does. The really odd thing is that when I just get garbage (different baud rates) some of those characters that don't work will come up.

I'm guessing I've got the right baud and there are just other problems.

I'm guessing I've got the right baud and there are just other problems.

The fact that you get many correct characters is a good sign. Look around for other serial LCD implementations and see if any of their commands work.

It will be easier to see any patterns between what does display and what doesn't if you use a better ASCII chart (one that has 'a' and 'A' on the same row, for example). Follow the link to 'An expanded ASCII chart' at http://web.alfredstate.edu/weimandn.

Don

I'm now assuming that the display is bad. Either it came that way or I messed something up in trying commands at random. Unfortunately the other 421 displays are locked up at the FabLab (where I found them) and it won't be open till January. Hopefully I can convince security to let me in on Monday.

I'm now assuming that the display is bad. Either it came that way or I messed something up in trying commands at random.

I don't think that either is likely. Have you tried the suggestions in my previous link?

Don

Holy crap! It's a parity problem. Bytes with odd parity are the only ones that work!

Thank you so much. I was about to just cast these aside.

Ok, so how do I change the hardware serial to use even parity? Should I just change the register manually or is there something in the library to do that?

Again thank you!

how do I change the hardware serial to use even parity

Sorry, I can't help you there - but that may not be the problem. Most run of the mill serial protocols use 'no parity' and that's probably what the Arduino routines use as well. If your display were expecting either odd or even parity then nothing would ever be displayed since the number of bits received would always be wrong. I think you are on the right track but it will require some more detective work. Did you redo your previous work on the ASCII chart I recommended?

I suppose if I had one of those displays I could tinker a bit....

Don

I just manually changed the register after enabling serial. In case someone else is having this problem:

UCSR0C |= UPM01; //Enable Even Parity, UPM00 Already 0

Sorry, I can't help you there - but that may not be the problem. Most run of the mill serial protocols use 'no parity' and that's probably what the Arduino routines use as well. If your display were expecting either odd or even parity then nothing would ever be displayed since the number of bits received would always be wrong.

I'm guessing what's going on is that the display was either not looking for a stop bit or the arduino was sending 2 stop bits(haven't looked into it yet). That means that the display was seeing the the next bit as the check sum bit. Of course since the stop bit is always a 1, it thought that any character with an even number of '1' bits was a transmission error. (Even parity)

I think you are on the right track but it will require some more detective work. Did you redo your previous work on the ASCII chart I recommended?

I did, that's when I realized that everything could be symmetrically divided in half four times.

I suppose if I had one of those displays I could tinker a bit....

They're not technically mine, I found them at the FabLab at school and was told I could have a few if I got them to work. PM me your address and if they let me have many I'll send one your way for helping me get them working.