ST25R3911B Hardware noise issues.

[Huzaifa_Tariq01]

Hi, I am using an ST25R3911B using the ST25NFC_embedded_library in polling mode on an stm32f103CBT6. In my program, I poll my ST25 and then move on to reading values from arrays of hall sensors (4 arrays of 16 sensors each) a total of 64 sensors. The issue I am facing is that, after a number of stable and precise repetitive readings, i get a complete reading with noise in the readings. when I shutdown polling of the ST25 in my software, the noise disappears. The left sensor array is most affected by the noise. 

Note:: Also the noise is not very random, every time the shift in sensor readings for each sensor is almost same as show in error log.

I have attached an image of the serial debug terminal highlighting the noise.

[Travis Palmer]

Hello Huzaifa_Tariq01,

If I understood your post correctly, you assume that the NFC reader is disturbing the hall sensors.

Hall sensor are based on magnetic sensing. In your setup, can they be disturbed by the magnetic field sent by the ST25R device?

You could check by taking another ST25R3911B reader (e.g. ST25R3911B-Disco board), emit a continuous magnetic field and bring it close to the hall sensors while reading them out.

BR Travis