How to use the ST25R95 on 14443-A anti collisions?

[CCHUN.1]

I have two ISO 14443-A tags

Tag 1 --> UID = 2DBADC81

Tag 2 --> UID = AE3A6F99

And I tried anti-collisions with two tags in field.

The sequence is as following:

>>> REQA "26 07"

<<< ATQA "80 05 04 00 28 00 00"

>>> Anticollision 1 "93 20 08"

<<< Answer anticollision 1 "80 08 AF BA FF 99 EA B8 00 00"

According to response B8 00 00, collision detected in index 0 byte and on index 0 bit.

Then I tried to get Tag 2 UID as following:

>>> Anticollision 1 "93 20 00 08"

<<< Answer anticollision 1 "90 07 FD 9F AC 07 B3 00 02"

The result is not any Tag's UID.

How do I send correct command strings to get Tag 1 and Tag 2 UID?

Thanks.

[Brian TIDAL]

Hi,

the firmware package X-CUBE-NFC3 contains the support for type A, B, F and V tags. In particular, the X-CUBE-NFC3 provides the support for the ISO/IEC 14443-A anticollision. A full demo of tag polling is provided for STM32 MCUs and can be easily ported on other MCU. The package is also scalable: if only type A is needed, the support of other technologies can be easily disabled to reduce the RAM/ROM footprint.

I would recommend to base you development on this package to reduce the effort versus developing from scratch.

Regarding your issue, the split frame "93 20 00 08" is incorrect and probably causing erroneous tag responses. Maybe 93 21 01 27 would be better. Anyway the full anticollision is available in the X-CUBE-NFC3 package.

Rgds

BT