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Author Topic: LCD shield - understand the mapping between Arduino and shield pins  (Read 700 times)
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Hi.

I hope you can see the image I have attached.

I bought a LCD shield, compatible with the DFRobot LCD Keypad Shield. Then I attached this shield to my Arduino Uno board.

I was trying to figure out how to access the Arduino pins through the shield, therefore I make a sketch that makes a led on digital pin 3 blink.

The system works if I connect the jumper wire to the spot marked with A in the picture, as expected, as that is the pin directly inserted into the Arduino header.

Then, I tried to attach the wire to the hole marked with B, as that is next to A, but the system didn't work. I had to insert the jumper wire as shown in the picture.

To me, that is totally counterintuitive as the hole I am using is next to pin 4 of Arduino, not pin 3.

Am I missing something? How could I have anticipated that? Is there a standard for how shields map Arduino pins?

Thanks a lot for your help!
Dan


* P1010669.JPG (100.69 KB, 486x334 - viewed 27 times.)
« Last Edit: November 23, 2012, 04:43:09 pm by dan_plan » Logged

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Where did you buy that shield? Does the seller provide a schematic?
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Thanks liudr for your help.

I bought it on eBay from a supplier based in Hong Kong.

Yes, I found the schematics - I have attached it.

But I can't find it in there how I could find out about the issue I am talking about - don't you need the PCB layout to see that? - sorry I am a newbie.

* schematics-v1.0-dfr0009.pdf (48.42 KB - downloaded 10 times.)
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Quote
Yes, I found the schematics - I have attached it.
That's more like a wiring diagram than a schematic (regardless of how they name the file).

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I was trying to figure out how to access the Arduino pins through the shield, therefore I make a sketch that makes a led on digital pin 3 blink.
According to that diagram, near the upper left corner, Arduino digital pin 3 (D3) is connected to pin 4 of J5 on the shield.

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... don't you need the PCB layout to see that?
A photo of the shield might provide the information.

Don
« Last Edit: November 23, 2012, 07:39:04 pm by floresta » Logged

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I bought a LCD shield, compatible with the DFRobot LCD Keypad Shield.
That looks more like a "Cytron LCD Keypad Shield for Arduino" but D3 goes to pin 4 of J5 on that board as well.
http://www.cytron.com.my/usr_attachment/LCDKeypad%20Shield%20SCH.pdf

Don
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Apart from the pin layout, you should solder some female pins on the board to have some reliable connections.
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