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Support Forum » LCD project, no display

August 02, 2011
by edb
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I recently received my Nerdkit and yesterday wired the sample circuit. I get no visible response on the LCD panel, and have checked voltages and included below, along with a picture of the wired kit. Notice that I chose to use colored wires to the LCD coded as: red +5V, green ground, blue contrast, yellow data signals. I also moved the voltage regulator, resistor and associated wires down one pin to avoid using the end row (personal preference).

Following confirmed with multimeter:

Battery 9.6 V Regulator out 4.67 V Both rails 4.67 V pin 1, 7, 20 & 21 MCU 4.67 V Resistor 0.97 k

From LCD pin 3 to ground (drop across resistor):

370 mV

From MCU to LCD pin:

pin 4 4.67 V pin 6 fluctuating around 10 mV (9 mV to 11 mV) pin 11 fluctuating slightly 4.2 V to 4.6 V pin 12 fluctuating 40 mV to 60 mV pin 13 fluctuating 40 mV to 60 mV pin 14 fluctuating 4.2 V to 4.6 V

I assume fluctuation not precise due to meter limitations, possible indicating MCU signals.

Please let me know if you see anything terribly wrong 'cause I'm stymied ...

Thanks, Ed

August 02, 2011
by Rick_S
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I don't know if it's the angle of the photot or not, but it appears your crystal is off by 1 row. Again, that may just be the photo. Also maybe the angle, but it looks as though the 4 LCD data wires may be shifted 1 position. (how many empty spots do you have at the end of the connector? There should be 2)

Other than those possibilities, I don't see anything that stands out.

Rick

August 02, 2011
by Ralphxyz
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What happened to your breadboard on the left side? It looks like it was severed (chopped off) roughly.

It's missing rows 1 and 2.

Your wiring looks good but I'd take it apart and redo it.

It's hard to tell exactly what the two green (GND) wires are doing but I asume they are run to ground.

You might want to move the two ground wires up to row 8 and 9 the same thing with your red power wire in case the breadboard got damaged on the end.

Ralph

August 02, 2011
by edb
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Ralph, no there's nothing wrong with the breadboard, you're seeing the edge of the box I have this sitting in. Green wires are grounded.

Rick, there's supposed to be 2 open pins on the end of the LCD? Wow, I guess I can't missed that in the project photo. I double checked and that's it, THANKS!

August 02, 2011
by Rick_S
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No problem, glad you are up and running. Thumbs Up BTW, Page 29 of the manual has a chart and photo showing the exact pins from the breadboard to the LCD connector. Wink

Rick

August 02, 2011
by edb
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Yeah, that's where I double checked. The picture on page 30 is the one that 'fooled me'. Thanks again.

August 02, 2011
by Rick_S
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Yeah, I saw that one too. From their angle I could see it looking shifted.

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