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Topic: LCD shield - understand the mapping between Arduino and shield pins (Read 756 times) previous topic - next topic

dan_plan

Nov 23, 2012, 10:27 pm Last Edit: Nov 23, 2012, 10:43 pm by dan_plan Reason: 1
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

liudr

Where did you buy that shield? Does the seller provide a schematic?

dan_plan

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.

floresta

#3
Nov 24, 2012, 01:37 am Last Edit: Nov 24, 2012, 01:39 am by floresta Reason: 1
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).

Quote
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.

Quote
... don't you need the PCB layout to see that?

A photo of the shield might provide the information.

Don

floresta

Quote
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

liudr

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

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