Missing radio on NRF52832

[Ekorre]

I am getting no radio (as in not being able to pick up advertisements packets) from my custom nrf52832 board. The antenna design is a hack so I am not looking fo stellar performance, rather signs of life. It is a chip antenna (2450AT18A100) directly connected to the ANT output via a want to be 50 Ohm trace.

What I have done so far:

• Confirmed the design on the nrf52-DK board, works.
• Measured the crystal to 32 MHz and confirmed life from the software.
• Soldered a 60 mm copper wire to the chip antenna pad (with the antenna removed), still nothing (I have gotten away doing this before).
• Measured the air spectrum between 2402 and 2480 MHz to see if turning the circuit on and off makes a difference. Lets pretend that makes sense. Saw no difference in the very crowded range. I lack equipment to perform any proper measurements.

It is supererogatory to say that I do not know what I am doing. What I am looking for are hints on what to check, what I might have missed and if there is something that can be done in software to either help or troubleshoot. I will add a matching network on the next design. Before I bin the board I would like to know that I tried what I could.

Any ideas?

[Wojtek]

Does the code run correctly? Are you able to debug?

[Hung Bui]

Using a copper wire as an antenna usually helps to get some signal even though it's not tuned and matched. There must be something else is wrong. As Wojtek asked, have you made sure the code run correctly, no assert ? Which code did you use ? If you test with BLE, you need to flash the softdevice first. You can also test with the example\peripheral\radio example or the ESB example in our SDK to verify the operation of the radio, you have full control over the RF channel you want to use there.

If it doesn't work, please upload your schematic, layout and a photo of the board.

[Ekorre]

Hello and thank you for the comments!

I did discover the radio_test demo and really appreciate that you can select just about any pin as serial interface (as a feature of NRF) and control said demo.

I have to clarify. The application software was running like intended on the NRF52-DK board so I am loading the SD and app just fine.

Now to the good news. All seem to work and what made the difference was replacing the oscillator twice. Either I am junk at soldering or something else is up.

I use CSTCW32M0X51-R0 (PDF: www.murata.com/.../pdfdownloadapi as oscillator and cannot really find a reason not to. Is there one?

Something to bring home from this is the radio_test mentioned by Hung Bui above so I am marking that as the answer.

Again thanks!

[Hung Bui]

The CSTCW32M0X51-R0 doesn't seem very right. The Frequency tolerance of 0.5% wouldn't meet the minimum requirement for Radio activity which is 60ppm.

[Ekorre]

Ouch, what a mistake. That is it. Again thank you!

I went with the Epson FA-128 10 ppm crystal and added a matching network in a new design. However since I replaced the oscillator on the current board everything works as far as proof of concept for the software (I know I am pushing my luck though).