Hi,
We have a custom board with nRF52832 QFABB0 chip. High frequency crystal used is 32MHz (Part No: ECS-320-8-37CKM) with two 12pF load capacitors (Part No:80-CBR04C120F5G).
Issue: After using our board for a couple of days, sometimes the board stops advertising upon startup.
Observations when this happens:
1. Only the advertising fails to start. When connected to SES via programmer, the code runs (SES shows "Running") and all the logs including "Fast advertising" appear in the terminal in debug mode.
2. All the voltages are correct at all Vcc points.
3. Jlink detects the board and "connect" command on terminal works. Able to reprogram the board also.
Upon analysis of the board, it turns out that one of the load capacitor of the crystal has failed (Capacitor failure is usually detected via multimeter impedance check across the load capacitors - we get an impedance in kiloOhms range if it failed as opposed to MegaOhms range when everything works well)
After replacing the failed load capacitor with a new 12pF capacitor, everything works well - i.e. code runs with logs appearing on SES terminal, SES shows "Running" and advertising works with expected RSSI (observed via nrfConnect App on iPhone).
Any idea why this might happen?
Attaching the layout of the crystal with accompanying load capacitors.
Four pads marker 01-NS7, 02-GND, 03-NS9 and 04-GND is how the crystal is placed.
