Reply To: Mifare Plus X switch from SL1 to SL3

Forum MIFARE and NFC Reader IC`s Mifare Plus X switch from SL1 to SL3 Reply To: Mifare Plus X switch from SL1 to SL3

Re: Mifare Plus X switch from SL1 to SL3

15. March 2018 at 18:53
Hi Christian,

The solution I found is to deactivate the tag to sleep mode and reactivate it while specifying the ISO-DEP protocol and interface (ISO-DEP == Layer 4 communication).

For hardware/historical reasons I was forced to spin my own state machine implementation, so I'm sending the commands manually.

When I put an SL1 tag in the field I see it activate using the Frame RF interface and Protocol T2T (are you the same?).
At this point, I have an active tag (RFST_POLL_ACTIVE).
I can sleep the RF_DEACTIVATE_CMD(sleep_mode), at which point the tag enters RFST_W4_HOST_SELECT.
From here, I reactivate the tag using RF_DISCOVER_SELECT, but I specify the the protocol as "PROTOCOL_ISO_DEP" and the interface as "ISO-DEP RF Interface".
If all went well you should receive an RF_INTF_ACTIVATED_NTF with the ISO-DEP interface and protocol.

If you're using the linux_libnfc-nci library (this is open source), I think they provide a function that does this:
nfcTag_writeNdef() in src/include/linux_nfc_api.h
If you follow the call stack down, I think the nuts and bolts are in:
reSelect() - src/service/interface/nativeNfcTag.cpp

If you're using the TapLinx SDK, I'm unfortunately not sure. I would imagine that they have a command similar to the linux libnfc-nci library that will do it all for you. If not, there must be functions to send deactivate and discover select commands.

Once the tag reactivates using ISO-DEP protocol and interface, you should be able to authenticate with the Level 3 switch key.

Hope this helps,

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