LCD Display problem, strange characters, display broken?

Testing/Troubleshooting
1

Hi,

I just installed an LCD display to my Midio128 and got it to display text sent from an external application (I want to use it as Hauptwerk status display), but somehow it displays very strange looking things.

This is what it looks like when I just send it a sequence of “0” and “8” characters. In both lines characters 9-11 display garbage.

Is the display broken, could this be a soldering problem or do you have any idea what could cause this?

Any help is greatly appreciated.

Reiner

2

hi; triple check all the connections and look for shorts; you can use the 2 schematics (lcd/core) so you can measure directly at the PIC pins

or upload MIOS again (what did you see on lcd with only MIOS), to be sure it’s not a mistake you made with the configuration of the MIDIO128.

cheers, marcel

3

I don’t know, but the way it’s rearranging lines on the screen, outside of their designated character posistions, looks like it might be a dud LCD… but a short circuit can make a device do strange things…

4

Hi Reiner,

such an effect could happen if the external application continuously updates the screen. A LCD isn’t a TV screen, it doesn’t need to be refreshed - just send the SysEx only if something has changed on the text output, and not permanently.

Alternatively you could use LCD command 01 instead of 00, because 00 always clears the screen before characters are written, and this causes a flickering effect.

This is just an assumption (you haven’t mentioned, how your application is working)

Best Regards, Thorsten.

5

Hi all,

thanks for the replies.

Just to clarify how the output is produced:

I changed the midio128 application to not update the screen (basically commented out the lcd-handler functions).

Now mios can be used to display messages on the LCD. I am only sending the corresponding sysex-message (actually using 00, but I don’t think clearing the display is the problem) once (using Midiox for testing) and then the message, in the example a sequence of "0"s and "8"s, just stays on permanently. So there is no flickering involved.

It appears as if vertical lines get scrambled (same positions in both display character lines).

BTW, when mios is booting, it displays its copyright notice, with the characters in the same positions being garbled.

Actually I cannot think what wiring problem could cause something like this, but then I also don’t know how data is sent to the display anyway.

So the question remains:

Is it likely that the display is broken (since it is new I could send it in for replacement) or could this be a wiring problem? (Actually the wiring looks pretty good).

Regards

Reiner

6

Yes, in this case it’s very likely that the display is broken

Best Regards, Thorsten.

7

Thanks again,

I’ll have it replaced and report back!

Best wishes

Reiner

8

Just to finish this up,

I received a new display from Reichelt yesterday and it now works perfectly!

Thanks again to all who replied

Best wishes

Reiner