Hello STM Community,
I'm currently working on a project involving the ST25DV04KC-IE8C3 NFC chip interfaced with the STM32L496ZG microcontroller. I've encountered an issue where the performance of the NFC chip deteriorates when a magnet is brought near the system, specifically related to the operation of a magnetic switch that generates interrupts.
Problem Description:
- Components: The NFC chip is located approximately 3.6 mm away from a magnetic switch (RR132-2E32-551).
- Issue: When the magnet is brought close to the magnetic switch, it appears to cause delays in counting and issues with I2C communication. Specifically, I suspect that the magnetic field is affecting the NFC chip's operation, leading to unexpected behaviour or interruptions that impact the STM32’s performance.
- Effects on System:
- Interruption in the NFC communication.
- Possible noise was introduced on the I2C bus.
- Delays in processing and timing, particularly in counting routines.
Troubleshooting Steps:
- I’ve monitored the interrupt lines and found unexpected behaviour, suggesting that the magnet may be inducing noise or causing the NFC chip to misbehave.
- I am considering moving the NFC chip to the bottom layer of the PCB and implementing shielding to mitigate the interference.
PCB Design:
I have attached a photo of the PCB layout for your reference. I would greatly appreciate any feedback on the design or suggestions on mitigating this issue!
Thank you for your assistance!
