Anticollision on MFRC630

[loichenninot]

Hi,

I'm using the MFRC630 and I'l facing a strange behaviour. For information I used also the CLRC663 and I can see the same issue.

The byte where the collision has been detected by the reader is never present in the Fifo.

Here an example of my issue:

The third byte is having the collision at position 20, thus 3 bits are valids on the third byte. When I read the fifo length register, it returns a length of 2 and in the fifo the third byte is not present, even if I read more bytes. Consequently, I cannot continue the anticollision procedure.

I'm missing something?

I have read the demo kit code example and I cannot see any particular treatment to get the last byte.

I have the bit LoAlert set but when I uses only one card, this bit is also set and it seems not particularly anoying.

Any idea?

Thanks in advance

[loichenninot]

up.

Any ideas Ivan?

Thanks in advance

[loichenninot]

Hi Ivan,

I have followed your advices and port the NXP reader library to my project.

I have exactly the same behaviour. On the first collision, the reader does not give me the value of the byte where the collision occured.

Ex:
Tags UIDs
tag 1  : 88 04 4A 6C 9A 74 4D 81 00 00 00
tag 2  : 88 04 23 5E 9A 74 4D 80 00 00 00ATQA: 26
ATQA answer: 44 00
COMMAND: 93 20
ANSWER: Fifo len: 2, Fifo content: 88 04
rxbitctrl: 0
Collision at 17

I was expected to have the fifo length to 3 and give me the first bit which is '0'. It is surprising because the reader sees exactly the position of the collision.

Do you have any ideas why the reader does not give me the information I need? What could be the root causes.

Best Regards,

Loic

[IvanRuiz]

Hello,

Could you please provide more information about your project?

Are you taking as reference the NXP NFC Reader Library? If so, which example are you working with? Could you also confirm the Host MCU which controls the MFRC630?

Thank you.

Regards,

Ivan.

[loichenninot]

Hi Ivan,

I'm using an ESP8266 as host controller, using SPI to drive the CLRC663.

I have found some drivers on the web and they seems to work, except that

the last byte of the card asnswer is never available in the fifo during a

collision .

I have read the NXP drivers, found on NXP website, and the driver I have

are the same during tha collision routine.

What could cause this behaviour? I suspect a bad level a the reception

part... I tried everything and I'm not able to get it work. I changed the

resistor of the return part from 12K to 22K and it does not change the

behaviour.

Any idea?

Regards,

Loic

2018-02-21 22:11 GMT+01:00 IvanRuiz <admin@community.nxp.com>:

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Re: Anticollision on MFRC630

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[kosster]

Did you fix the issue with reading the fifo on collision? I have an identical problem, and in case a fifo collision occurs at the beginning of a byte, it indicates that the byte is empty. Reading the entire fifo does not improve the situation. Information on the data is still missing. The collision error is of course detected as well as its position.

[IvanRuiz]

Hello,

The software examples of the NFC Reader Library are for LPC1769. We recommend to first start on our software and hardware to then move to another platform (if required).

Please refer to the following link for the development kit:

OM26630 | CLRC663 plus NFC Development Kit|NXP 

Regards,

Ivan.