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Topic: GLCD library version 3 (Read 82 times) previous topic - next topic

marcus barnet

No, I don't.

However, pin 14 of my LCD is connected to Arduino reset. Is it correct?

(I tried also to connect pin 14 to +5VDC, but it's the same)

The problem is that sometimes the library works well (few times) and all the other times it prints weird characters..


No, I don't.

Weird characters? I think it may be time for some photos/video.

What about: (from earlier)
The supply voltage?
The source of the voltage?
Was the module ever incorrectly hooked up?
Any photos of your setup?

marcus barnet

Jun 26, 2012, 03:37 am Last Edit: Jun 26, 2012, 03:45 am by marcus barnet Reason: 1
These are some photos about the display.
The first and the second photos are for Hello World example while the third is for Life example.

I didn't take the photo about the wiring since it is not possible to understand something since there a lot of wires, all with the same colour.
However, they are all ok since display works fine sometimes.

I have no other device attached to my Arduino UNO rev3, only the display.
I have Serial library since i write something on the serial port just to see if my program is working.

Supply voltage is +5VDC from Arduino which is also the source voltage; i'm not using any additional source.
The module was never been connected with a wrong configuration.


That is very strange.

The glcd memory is mapped 8 bits at time vertically. Each 8 vertical pixels is
written at once. The text is corrupted within that 8 bits.

It still could be a wiring issue.
Broken, disconnected, or poor connecting wires can create some really strange problems
as the signals float around and vary depending on loading and what is being done.

Diags is going to be the best bet for diagnosing the problem.

From looking at the display data bits 2 and 3 (glcd module pins 6 & 7) seem to be having issues.
Take a very close at the wires on those connections.

When diags runs what does the initial animation pattern look like?
(It should be a triangle from upper left to lower right).

Does diags get past the initial walking ones test?

You measured the voltage at pins 1 & 2 on the glcd at exactly 5v?

Can you get a clear shot of the wires so I can see the solder joints?
What is on the other end of the wires?
Are the wires going into a breadboard, or directly into the Arduino board?
How long are the wires and do they have any breaks or re-connections in them before
being connected to the Arduino headers?

--- bill

marcus barnet

Between pin1 and pin2 there are 5.01VDC.
I check the continuity with a tester on all the connections and they are all ok.
Unfortunately, i tried to take a photo about the wiring but it is not clear since there are too many wires.
Pins 6 and 7 are ok.
Wires are very short, about 10 centimeters and they do not have reconnections or breaks: they directly go to the atmel microcontroller.

I'm using a perfboards, so all the wire are soldered.
However, i tried to connect and re-connect the display to my arduino several times and all the time connections are ok but there are strange characters on the display.

The most important thing is that when I run the diagnostic sketch, I'm able to see the triangle which is under all the strange characters and the black pixel lines.
As you can see in the previous photos, sometimes the correct characters are in background since strange characters and black lines are foreground.

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