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How to get a RF baudrate of 424 kbps with the ST25R95 with ISO/IEC 14443 Type A?

StuN1
Associate II

Hello everyone,

A RF baudrate of 424 kbps with ISO/IEC 14443 Type A seems possible in the ST25R95 datasheet (page 15).

I checked the SPI bus and this SPI frame is sent, as expected :

controlcommandlength<Protocol><Parameters>...  
sendProtocolSelectlengthISO/IEC 14443 Type ATx and Rx RFdataratePPMMDD
0x000x020x050x020xA00x000x000x00


There's no error code until I try to read if a tag is present :

controlcommandlength<Data>...
sendSendRecvlength  
0x000x040x020x520x07

wait for ST25R95 nIRQ_OUT ... then

 control   
 read...  
master send:0x020x00...0x00
ST25R95 response:0x0E0x86...0x00

There I get 0x86 : "Communication error"

*It works fine when "Tx and Rx RFdatarate" is 0x00 (106 kbps). I tested with SPI speed of 625 kHz, 1.25 MHz and 2.5 MHz (I know it's max 2 MHz for ST2595, but those speeds all works with the 106 kbps RF baudrate)


So, how to get a RF baudrate of 424 kbps with the ST25R95 with ISO/IEC 14443 Type A?

(other questions: What is the data we need to send in the SendRecv? (0x52 and 0x07 means what?) Where can I find explanations to the comments of page 22?)

Thanks!

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1 ACCEPTED SOLUTION

Accepted Solutions
Brian TIDAL
ST Employee

Hi,

higher bit rates are supported on T4AT tags (i.e. not supported on T2T tags). Which tag do you use (manufacturer and model)?

Moving from the default 106 kbps to higher bit rate can be done after the RATS/ATS exchange when entering in isoDep protocol.

If you plan to use this, I would recommend to use the RFAL NFC stack available on st.com. See ST25 embedded NFC library. You can use the polling example and set the maxBR in discParam to RFAL_BR_424.

Regarding your  additional question, 52h is an ISO14443-3 WUPA command. It is described in the ISO14443-3 document. 07h is the transmission flag meaning that the WUPA is 7 bits frame with no CRC (see table 16 in the ST25R95 Datasheet). According to the ISO14443, the WUPA command has to be sent with the default 106 Kbps bit rate.

Rgds

BT

 

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3 REPLIES 3
Brian TIDAL
ST Employee

Hi,

higher bit rates are supported on T4AT tags (i.e. not supported on T2T tags). Which tag do you use (manufacturer and model)?

Moving from the default 106 kbps to higher bit rate can be done after the RATS/ATS exchange when entering in isoDep protocol.

If you plan to use this, I would recommend to use the RFAL NFC stack available on st.com. See ST25 embedded NFC library. You can use the polling example and set the maxBR in discParam to RFAL_BR_424.

Regarding your  additional question, 52h is an ISO14443-3 WUPA command. It is described in the ISO14443-3 document. 07h is the transmission flag meaning that the WUPA is 7 bits frame with no CRC (see table 16 in the ST25R95 Datasheet). According to the ISO14443, the WUPA command has to be sent with the default 106 Kbps bit rate.

Rgds

BT

 

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

Thank you Brian,

I use Type 2 tags, so I guess higher bit rates are not supported. I investigated this issue after trying that example code with discParam RFAL_BR_424 unsuccessfully.

I will take a look at ISO14443-3.

Do you have T4T tags to recommand?

Regards,

Hi,

I can only recommend ST tags such as ST25TA02 but this tag supports only 106 Kbps.

Rgds

BT

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