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2.8" Adafruit 335 no picture-resolutions?

by eljainc on Mon Nov 19, 2012 5:45 pm

I'm starting a new thread for this issue.

I have the 2.8" Adafruit and am connecting it to an Arduino MegaPro. I have D0-D7 on the touchpanel connected to 22-29 on the MegaPro. The touch signals are connected. I have now the backlight powered with +5V. The control lines are connected so the C/D, CS, WR and RD signals connected to the appropriate analog pins on the Arduino. I'm still getting no picture. I have
a sketch that is supposed to draw to the screen. I'm still getting no output. It is just a white screen (backlit). Is there another way I can test the setup?
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Re: 2.8" Adafruit 335 no picture-resolutions?

by adafruit_support_bill on Tue Nov 20, 2012 6:14 am

Are you using the 2.8" shield, or breakout?
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Re: 2.8" Adafruit 335 no picture-resolutions?

by eljainc on Tue Nov 20, 2012 8:12 am

We're using the 1x20, and have soldered headers. We're not using a shield or breakout board on the Arduino. We've soldered headers in a similar manner
that we did for the LCD, then use C-Grid or similar connectors on the male header pins.
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Re: 2.8" Adafruit 335 no picture-resolutions?

by pburgess on Tue Nov 20, 2012 3:16 pm

How long are the wires between the Arduino and LCD? Try to minimize this length, as they may be vulnerable to interference.
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Re: 2.8" Adafruit 335 no picture-resolutions?

by eljainc on Tue Nov 20, 2012 4:13 pm

The parallel data (D22-D29 from Aduino) cable is about 6" long. The LCD control signals (C/D, CS,
WR,RD) cable is about 12". The Touchscreen X/Y signal cable is about 10" long.
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Re: 2.8" Adafruit 335 no picture-resolutions?

by pburgess on Wed Nov 21, 2012 1:27 am

That's long enough to give me pause...I usually use the little 3" pre-cut jumper wires when interfacing these types of displays.

One way to check if it's interference is to look at the driver chip ID that's printed in the Serial Monitor. If it changes from one run to the next, quite likely interference. If it's consistently the same number, then more likely a wiring issue.
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