LCD half display OK half matrix - old Hitachi controller.

I have an older 16x2 display I have experimented writing into. It displays OK, but only half of the text..On both lines. The rest of it is partial matrix ( 5x9) dots, from single column to three. It won't clear (lcd.clear) and the garbage appears immediately after the first print. If I remember right the display memory is not continuos on LCD with the Hitachi controller. So how do I find if the LiquidCrystal library supports that before I go back to the pBasic code to rebuild it for C. Thanks for reading. Vaclav .

Is this your first time asking for help on this forum ?

It displays OK, but only half of the text..On both lines.

You haven't mentioned which half, the left eight columns, the right eight columns,, the center eight columns, every other column, etc.

Most likely you mean one of the first two choices and you will find an explanation of what is probably happening in a recent thread: --> http://forum.arduino.cc/index.php?topic=199971.msg1475248#msg1475248, specifically replies #2 and #3.

Don

I don't believe you mentioned whether it was parallel or serial. Is the answer to that in the Hitachi controller info ?

raschemmel: I don't believe you mentioned whether it was parallel or serial. Is the answer to that in the Hitachi controller info ?

It has Hitachi HD44780 controller which always been parallel. I run it in 4 bit mode and the characters 0 - 7 are OK on both lines. The memory "gap" is between first and second row, where the internal memories are. I am stumped. Perhaps it is goner, got another one on the way. Vaclav

Vaclav: I am stumped. Perhaps it is goner, got another one on the way.

It's sounding somewhat like that.

We are still somewhat curious however, as to exactly what it looks like - we'd love to see a photograph! :D

It just possibly could be an LCD connection problem and "tweaking" the bezel mount might fix it or - more daring - re-seating the LCD as in my other explanation.

maybe it's broken break easily :drooling_face:

Sorry guys , I cannot get the jpg image to paste here I'll keep trying Vaclav

Click "Additional Options" below the edit box. Click the "Browse..." button next to "Attach:". Find your picture, select and upload it. The picture will be displayed below your posting in a thumbnail type way, and clicking it will expand it to full size. Resize the picture if it is too large, before uploading it.

I am stumped. Perhaps it is goner, got another one on the way.

Are you still stumped after reading the information in the link I posted earlier (reply #2)? Paul posted a link to the same location in reply #5.

Don

OK I got the picture filename next to Browse button , but no icon anywhere.
Please help what is next.
Thanks for you help.
Vaclav

Must have been magic, but the picture is here. It is taken using mirror , but you can see the garbage on columns 8 up. I wenht thru all the posts and it did not really give any other ideas what could be wrong. The only thing is puzzling - the dot matrix is definitely 5x9 . I recall that somewhere in the documentation ( I got old paper copy somewhere) there is a setup to output only 8 characters in 5x7 format. Anyway I am using the LCD just to trace my progress thru development and 8 characters display is OK for now. As soon as I get the new LCD I will wire it up and then we all know the answer! Thanks for all you help. Cheers Vaclav

It is taken using mirror , but you can see the garbage on columns 8 up.

So we finally have the verification that the speculation in reply #2 was corect. This is like pulling teeth.

I wenht thru all the posts and it did not really give any other ideas what could be wrong.

So you have tried putting pressure on the bezel and nothing changed?

The only thing is puzzling - the dot matrix is definitely 5x9 . I recall that somewhere in the documentation ( I got old paper copy somewhere) there is a setup to output only 8 characters in 5x7 format.

Have you considered how the underline cursor is implemented?

Don

floresta:

It is taken using mirror , but you can see the garbage on columns 8 up.

So we finally have the verification that the speculation in reply #2 was corect. This is like pulling teeth.

Well you did not get my explanation and I do not sit in font of PC all day.

I wenht thru all the posts and it did not really give any other ideas what could be wrong.

So you have tried putting pressure on the bezel and nothing changed? Yes

The only thing is puzzling - the dot matrix is definitely 5x9 . I recall that somewhere in the documentation ( I got old paper copy somewhere) there is a setup to output only 8 characters in 5x7 format.

Have you considered how the underline cursor is implemented? Yes

Don

Using WireWrap, eh?

Groovy!

(No problems with unreliable connections.)

Where's your code ? I can see the "Hello, world !" message. It is spread over 2 lines (0802 instead of 1602 ?). Is it meant to be that way or should it be on one line and the second line have some other message ?

Paul__B: Using WireWrap, eh?

Groovy!

(No problems with unreliable connections.)

Far out! Yes, I just love the step by step process using it. Easy to screw-up and fix one wire at time! I should post the "whole board"! Vaclav

A new, very expensive part ($2) arrived and the old smoked one is on its way to the landfill. Learned some new stuff about how to check hardware and was reminded how NOT to write library using functions a) not checking parameters passed to them b) not returning success or failure values. Cheers Vaclav

Hi, can we have a clear picture of the back of the display, they have enough numbers on them to help identify the exact model. You have not told us the model number.

Tom...... :)

TomGeorge: Hi, can we have a clear picture of the back of the display, they have enough numbers on them to help identify the exact model. You have not told us the model number.

Tom...... :)

Sorry, nope, it is gone.