ST25R3916B I2C Reference Design

[SRauh.1]

Hello,

we designed a PCB with an ST25R2916B which should connected via I2C.

As basis for our design we use the schematic for the X-Nucleo-NFC06A1.

Our Problem:

If we connect the modified (UM2616, Chap. 3.5.1) X-Nucleo-NFC06A1 to a Nucleo32 running the NFC_Polling example, it works quit well.

But if we connect our own design to the Nucleo32 no I2C communication comes up.

We already study the datasheet in detail, but we can't find any reason that the comparison test fail.

Question:

Is there a reference design for the ST25R2916B with I2C connectivity which we can follow?

Our design is:  

Thanks for your help,

Sebastian

[Ulysses HERNIOSUS]

Hello Sebastian,

there is now the X-NUCLEO-NFC08A1 (driven by the same X-CUBE-NFC6 package). In my view it should be pretty much identical exact for the newer chip.

From a first shot I would look at pull-ups of SCL and SDA and verify them, also perform some measurements on these lines (oscilloscope).

One remark on your schematic: I2C_EN should be be connected to VDD_D, with your schematic you may experience increased power-down current.

Best Regards, Ulysses

[SRauh.1]

Hello Ulysses,

thank's for your answer.

As you mentioned, we checked the pull-ups for the SCL and SDA.

We used 10kOhms for it.

We also do measurements, but the lines are static.

Is it necessary to contact any further port (e.g. nBSS, IRQ) which we have left unconnected in our design?

Best Regards,

Sebastian

[Ulysses HERNIOSUS]

Hi Sebastian,

for real operation I recommend also connecting IRQ to be able to react on events from the NFC chip.

If SDA and SCL are completely static then you need to look at MCU side first. Until the first ACK from the I2C slave (NFC chip) all data (slave address) is solely driven by MCU.

BR, Ulysses

[SRauh.1]

Hi Ulysses,

okay, we will check it in more detail, but the behavior seems very strange to me.

The X-Nucleo_NFC06A1 works well on the Nucleo F446RE, but the own board doesn't.

If you have any further idea to solve the problem, let me know.

Best Regards,

Sebastian

[Douglas MILLER]

This forum thread was marked by the moderator as needing a little more investigation, so a Support case was created in your name and will be handled off-line. Should anyone have any similar questions, please feel free to open a Support case directly at your myST portal: https://st.com/ols