UART interface with ST25R3911B-DISCO

[Stephen Eagle]

Posted on June 12, 2018 at 10:21

I am trying to interface with the ST25R3911B-DISCO board via UART.

Basically I want to send commands to the reader and then receive the response via the provided UART. I am planning on connecting the

ST25R3911B-DISCO board to an external MCU and thus want to use UART as the interfacing standard between the two.

I am struggling to find documentation on on how this is possible via the boards UART. Where can one find out what baud rate to use? And Is there a specific mode in which the 

ST25R3911B-DISCO board must be in for communication via UART to work? Also what commands are available and what type of responses can be expected from the boards UART.

Any documentation, assistance or pointers to help would be greatly appreciated.

The tag I have is the stock standard ST25TA64K that came with the 

ST25R3911B-DISCO kit.

#st25r3911b-disco #i2c-and-uart #ndef-st25ta64k

[Travis Palmer · Accepted solution]

Posted on June 13, 2018 at 10:31

Dear Stephen,

The ST25R3911B-DISCO provides two connectors to communicate with the STM32L4 MCU via UART (P202) and I2C (P203). You can find information about the layout in the user manual UM2042. Dependent on the UART port you want to use, you may need to close J201 and J202.

From HW point of view the 

ST25R3911B-DISCO is ready to exchange commands via UART and I2C. 

Nevertheless this functionality has not been implemented in our firmware. In order to do so, you will need to download the FW sources (

http://www.st.com/content/st_com/en/products/embedded-software/st25-nfc-rfid-software/stsw-st25r002.html

) and add the functionality according to your needs. 

The X-NUCLEO-NFC05A1 in combination with a NUCLEO-L476RG already has some basic ST-LINK-VCP-UART logging functionality implemented. 

BR Travis

[Stephen Eagle]

Posted on June 18, 2018 at 12:49

Hi Travis,

Thank you for the speedy reply! I will have a look at the firmware and see if I can add the UART functionality at a later stage

[Wmah.1]

I am also in a similar situation looking to use the I2C interface to perform tag detection, query and access, etc. I wanted to be clear there is currently no firmware in the DISCO board to support this through I2C...I must develop it myself?

[Ulysses HERNIOSUS]

Hi Wmah.1,

I am not aware of a ST25R3911B firmware talking I2C to the host. I am confident I would be aware if such exists inside ST.

However ST25R3916 has also an option of a direct I2C interface. But it may be too cumbersome to implement RFAL on your host?!

Regards, Ulysses

[Wmah.1]

Thanks Ulysses,

It's strange that the I2C interface is offered on ST25R3911B without any firmware support. I was hoping to use this EVB to quickly prototype my host with NFC capabilities without having to spin up a new PCB. The ST25R3916 appears to have the command interface I need to read and write tags. Hopefully there is an EVB for ST25R3916 with the direct I2C interface.

Thx again.

Wil

[Ulysses HERNIOSUS]

Hi Wil,

when designing boards it is a good practice to enable also future options. On the ST25R3911B-DISCO options for I2C / UART were foreseen but never used.

X-NUCLEO-NFC06A1 with X-CUBE-NFC6 can be used to run I2C. Please refer to the UM of X-CUBE-NFC6 for details.

Regards, Ulysses