NFC Shield fails when LED is connected to PIN 13.

Hello all,

I read that the status LED on the Duemilanove Arduino Board is connected to the DigitalPIN 13. If I connect a LED to it, it blinks with a simple program like this:

void setup(){
pinMode(13, OUTPUT)
void loop(){
digitalWrite(13, HIGH);
digitalWrite (13, LOW);

However, if I connect the NFC Shield to the Arduino board, and connect the LED on the same pins (13 and GND), the Shield does not work anymore.

Using the code on this page (, I get “Didn’t find PN53x board”.

Why does the board fail to work when a LED is connected to PIN 13? The Shield is detected when the LED is disconnected.

NFC Shield uses SPI (Pin 10-13).
If you use pin 13 for a LED, SPI cant work…

If the Arduino Shield uses SPI (Pins 10-13), then there is not much I can do with the board.

Of the simple things I want to do is display some Welcome information on an LCD screen with an RFID tag is brought to the Shield.

Most LCD 16*2 displays use 6 or more pins from Arduino (including pins 10 - 13).

A Google search led to this ( where I can use three PINS.

However, the PINs used in this minimalistic configuration use PINs 10-13.

  1. Does SPI will make a lot of simple task difficult.
  2. What work-around exists?

Thank you.

If you use a normal LCD you can use all Arduino pins for communication. Just change the pins in the source code.

For example use a Serial LCD … th=163_164
I2C Oled Display … th=163_167

Hi shailensobhee,

do you have the same problem, when you only connect your Arduino Board with the NFC Shield ? (I’am having such a problem :frowning:)