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iwanders / MFRC630

A library for NXP's MFRC630 NFC IC.
MIT License
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Help wanted with changeable uid #6

Open sgtJohnny opened 6 years ago

sgtJohnny commented 6 years ago

Hi,

I'm using your libray for my reader, but now i'm stuck with extending the functions. I want to support UID-Change on mifare cards. A library for the RC522 can do this by sending commands to the mifare card directly

If you check https://www.nxp.com/docs/en/data-sheet/MF1S50YYX_V1.pdf on Page 13 you can see the commands "Halt" and "Personalize UID". I need to send this commands,

I guess they are similar to the REQUA that already in your code. Any help on how to make a function that can send this commands?

iwanders commented 6 years ago

I guess they are similar to the REQUA that already in your code. Any help on how to make a function that can send this commands?

Both interact with the tag yes, but REQA is a low level wakeup command in the ISO14443 specification. The halt command is also low-level, the Personalize UID usage is not a low level command but instead it is a chip-specific instruction not described by the ISO14443 specification. It's communication at a much higher layer then REQA or halt would be.

The library already contains the auth, read, write MIFARE classic commands. Which are described in page 20-23 in the pdf you linked. If you compare the code of those commands with their datasheet pages you should be able to write a similar function that implements your Personalize UID Usage command. Those were the commands that were supported by tags I had lying around when I created this library, I know they work so they should provide you with a solid basis to go on. You likely have to authenticate with the tag first before you can do any meaningful interaction with the memory, for this you can take a look at the example dump function.

Read the datasheet thoroughly first, especially section 10 to confirm you actually need to implement this command. I don't think it does what you think it does, it doesn't modify the UUID as far as I can see, it merely allows you to select which UUID from sector 0 block 0 is used and how the UUID affects the anti-collision behaviour.

sgtJohnny commented 6 years ago

Thank you for your response, i sucessfully implemented and tested the function in my design, yes i do need the commands, since i use special cards that allow me to change the actual UID.

If you like, i can send you the code for the functions, since i changed the code to class-based i cannot make a request on github, but i could send you the code.