How to read data from my tag(NDEF messag) from CR95HF?

Jignesh · ‎2018-10-12

I have successfully communicated with CR95HF using usb to uart bridge using uart communication. I can read my nfc tag(BL654- type 2) UID using command send from terminal by selecting ISO14443-A protocol.

But I have problem with reading data from tag how to read data.

For infomation: when i read NFC tag(BL654) from mobile "NFC Tools" andoid application it displays my data wrote on nfc tag.

Thanks,

Jignesh Patel

Peter Boringer · ‎2018-10-15

Hello Jignesh,

If you are able to read the UID after the anti-collision and select command that means that your protocol and setup are well established.

Now by only reading the tag, using the read command you should receive Data.

In order to get the NDEF contents, as you want to read a NFC forum format on type 2, you have to read the CC(capacity container) file

located in block 3 according to the NFC forum document:

(Type 2 Tag Technical Specification Version 1.0 2017-08-28 [T2T] NFC ForumTM)

Byte 00 will indicate you are using a T2T code "E1"

Byte 01 Contains the Mapping Version for example code "10"

Byte 02 Will indicates the encoded size value of the T2T area ( T2T Area = Size*8)

Byte 03 Shows the read write conditions.

Then data can follow on next block, please refer to the NFC Forum T2T specification to check the NDEF organization/ decoding.

Hope it will help

Regards

PB

View solution in original post

Peter Boringer · ‎2018-10-15

Hello Jignesh,

If you are able to read the UID after the anti-collision and select command that means that your protocol and setup are well established.

Now by only reading the tag, using the read command you should receive Data.

In order to get the NDEF contents, as you want to read a NFC forum format on type 2, you have to read the CC(capacity container) file

located in block 3 according to the NFC forum document:

(Type 2 Tag Technical Specification Version 1.0 2017-08-28 [T2T] NFC ForumTM)

Byte 00 will indicate you are using a T2T code "E1"

Byte 01 Contains the Mapping Version for example code "10"

Byte 02 Will indicates the encoded size value of the T2T area ( T2T Area = Size*8)

Byte 03 Shows the read write conditions.

Then data can follow on next block, please refer to the NFC Forum T2T specification to check the NDEF organization/ decoding.

Hope it will help

Regards

PB

Jignesh · ‎2018-10-18

Thanks Peter,

I can read NFC NDEF content successfully by reading a CC file.

My requirement is to read NFC tag type2.

command to get tag detection is :

02020200 => set protocol

04022607 => get detection (87 00 in case of no tag detection)

Is there any way to get inerrupt on any pin or indication on uart when tag is deteted ?

currently i have to send command continously to check whether tag is detected or not. I am using UART communication.

Thanks,

Jignesh Patel

Peter Boringer · ‎2018-11-05

Hello Jignesh,

You are right in UART mode there are no way to generate a interrupt output signal and thus you need to poll forthe answer.

For info this option is available in SPI mode.

BR

PB