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I am electronics newbie but have some programming background. My current hobby project is to make a "thing" which does things based on which NFC badge is waved at it. The tutorial [1] I am following says to use RX/TX pins between my Raspberry Pi and the NFC breakout from Adafruit, this is all nice and dandy except that I have already used those pins for serial console so I can see the device boot up and/or crash down.

What is the easiest and cheapest way to get both working as I "planned", or is this just plain impossible?

[1] https://learn.adafruit.com/adafruit-nfc-rfid-on-raspberry-pi?view=all

Edit:

Okay, so after all it seems that it is possible to use SPI/I2C between NFC Breakout and Raspberry. This leaves console free as I wanted to, but raises new questions. I also happen to have 2.8" touchscreen from Adafruit (PiTFT) and that also wants to use SPI/I2C pins.

I found this [2] tutorial on how to connect similar NFC board using SPI, but I do not understand how "slave selection" works as there is no wiring for that. Or does that even need to happen... My new and improved question is, how to wire my NFC and display at the same time?

[2] http://blog.iteadstudio.com/raspberry-pi-drives-itead-pn532-nfc-module-with-libnfc/

closed as unclear what you're asking by goldilocks Dec 21 '14 at 18:00

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  • 1
    Have you checked to see if the Adafruit device supports an alternative link? Perhaps I2C or SPI? – joan Dec 3 '14 at 20:18
  • Or perhaps software serial... I'm sure a library exists for RPi somewhere. – baum Dec 4 '14 at 2:44
  • Supposedly libnfc works best with uart, but I'll take a look into that I2C/SPI business. Now, software serial sounds promising but raises questions about bootup messages, are those available or does the serial interface appear too late in the process. Or did you mean to use it with NFC breakout board, would that be simple to implement? – Mikko Dec 4 '14 at 6:31

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