ST25R3916B Custom Board Not Detecting Tags on Embedded Linux System

[dave100]

Hi,

I’m working with an ST25R3916B custom board connected via SPI to a custom embedded Linux system. The system is running the ST25R3916_v2.8.0_Linux_demo_v1.0, but it is unable to detect any NFC tags.

The issue seems to originate from the nfc_demo_st3916b application, specifically in st25r3916.c at the st25r3916OscOn() function. The application fails at the check on ST25R3916_REG_AUX_DISPLAY_osc_ok at line 287. To bypass this, I commented out the check, which allowed the application to run, but it still does not detect any tags.

Here’s what I’ve observed:

• With ST25R_SELFTEST defined in st25r3916.c, I see a 400 µsec pulse on the IRQ line when the application starts, and it runs without errors. However, no further pulses or signals are observed on the IRQ line afterward.
• When I define ST25R_SELFTEST_TIMER in st25r3916.c, the initialization fails on the second test at line 232, and I do not observe any pulse on the IRQ line at all.

I would greatly appreciate any advice or recommendations on what further steps I should take to resolve this issue.

Thank you and best regards,

Dave

[Brian TIDAL · Accepted solution]

Hi Dave,

The 27.12MHz oscillator seems to fail to start. I would suggest to check that this component is properly soldered and properly connected to XTI and XTO pins. Also probe the oscillator with a scope and make sure it is starting

Rgds

BT

[dave100]

Hi Brian,

Thank you so much for your quick and accurate response—it was spot on. I’ve made the necessary corrections, and the system is now working.

Your support has been invaluable, and I’m grateful for the guidance.

Thanks again!

Dave