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vlad_04
Graduate
October 20, 2025
Solved

X-CUBE-NFC6 I2C freezes

  • October 20, 2025
  • 2 replies
  • 245 views

Hi. I recently started using set "NUCLEO-L476RG" and "NUCLEO-NFC08A1"..
I launched the existing "NFC08A1_PollingTagDetect" project, which works via SPI, and everything worked fine.
Then I decided to redesign the project for I2C. I ran into some problems and questions.

Questions:
1) According to the "X-CUBE-NFC6" manual for implementing I2C:
3.5.1:
• solder ST2 and ST4 jumpers.
• solder R116 and R117 pull-up resistors.
• remove the SPI solder bridge.
• install the I²C solder bridge.

However, according to 6.2 of the same manual:
it is also necessary to "Connect jumper wires from ST2 to ST5 and ST3 to ST6."

Question: So, which step should I follow? Do I need to connect ST2 to ST5 and ST3 to ST6?

2) If I still need to connect ST2 to ST5 and ST3 to ST6, then ST3 is missing in the "NUCLEO-NFC08A1". What should I connect instead?

Problems:

What I did:
Hardware:
• solder ST2 and ST4 jumpers.
• solder R116 and R117 pull-up resistors.
• remove the SPI solder bridge.
• install the I²C solder bridge.
• solder ST2 to ST5 jumper.

Software:
• In the Cube MX project, I disabled SP1 and enabled I2C1.
• In the "X-CUBE-NFC6" settings, I selected I2C:

vlad_04_0-1760947281333.png

 

vlad_04_2-1760947333346.png

vlad_04_3-1760947364656.png

vlad_04_4-1760947386318.png

Problem description: Tag reading is unstable, specifically:
• when power is applied, initialization occurs intermittently (when all the LEDs start to light).
• when the field reading LED finally flashes, then when the tag is brought near the system freezes.

Could you help with that?

    This topic has been closed for replies.
    Best answer by vlad_04

    This manual is located at "C:\Users\UserName\STM32Cube\Repository\Packs\STMicroelectronics\X-CUBE-NFC6\3.1.0\Documentation" when I installed "X-CUBE-NFC6" via the CubeMX.

    I removed ST2-ST5 bridge and set 2.2K pull-up instead 10K and now it works.

    2 replies

    U
    Ulysses HERNIOSUS
    Technical Moderator
    October 20, 2025

    Hi,

    UM2616 Rev.2 does not have a ch. 6.2. Where did you find this?

    You should not need any flying wires. The ST2-ST5 bridge shouldn't hurt because it is the same pin of ST25R3916B (UM3007 + schematics/multimeter)

    Your problems sound as if you introduced some overcurrent. Please check your soldering. Then if still not operational then analyze using Logic Analyzer (SPI+IRQ) + vdd (Voltage and Current) probes.

    BR, Ulysses

      V
      vlad_04AuthorAnswer
      Graduate
      October 21, 2025

      This manual is located at "C:\Users\UserName\STM32Cube\Repository\Packs\STMicroelectronics\X-CUBE-NFC6\3.1.0\Documentation" when I installed "X-CUBE-NFC6" via the CubeMX.

      I removed ST2-ST5 bridge and set 2.2K pull-up instead 10K and now it works.

      B
      Brian TIDAL
      Technical Moderator
      October 20, 2025

      Hi,

      The information in section 6.2 of the Getting started document is incorrect. Since there is an internal connection between I2C_SCL and SPI_CLK, there is no need for a wire jumper between ST2 and ST5. The same applies to I2C_SDA and SPI_MISO. Additionally, there is a typo related to the non-existent ST3. Thank you for reporting this issue.

      Make sure to enable both I2C1 event interrupt and  I2C1 error interrupt. What value have you used for the pull up resistor? Make sure that the internal GPIO pull-up for the SDA and for the SCL are not enabled

      Why do you have USART2 interrupt enabled?

      Could you enable ST25R_SELFTEST and ST25R_SELFTEST_TIMER compilation flags?

      Could you connect a logic analyzer on SCL, SDA and Interrupt and provide the log file?

      Rgds

      BT

       

       

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