nRF52832 never appears on phone as an Adafruit Feather nRF52832

RE: nRF52832 never appears on phone as an Adafruit Feather nRF52832

0miker0 — Mon, 23 Nov 2020 15:50:52 GMT

Not sure what you mean but rotating the crystal 90 degrees to compensate for my incorrect footprint has fixed the issue. Works perfectly now.

Thanks!

RE: nRF52832 never appears on phone as an Adafruit Feather nRF52832

ketiljo — Mon, 23 Nov 2020 14:52:51 GMT

That should be ok. Is soldered properly? Can you do a test when you force the CPU to use the HFXO instead of the HFRC?

RE: nRF52832 never appears on phone as an Adafruit Feather nRF52832

0miker0 — Mon, 23 Nov 2020 14:47:36 GMT

Using this crystal that is 10ppm with 12pF capacitors. lcsc.com/.../SMD-Crystal-Resonators_TXC-Corp-8Y32000001_C409316.html

RE: nRF52832 never appears on phone as an Adafruit Feather nRF52832

ketiljo — Mon, 23 Nov 2020 13:50:09 GMT

What's the spec of the 32 MHz crystal you're using? It needs to have a total tolerance of 40 ppm or better. Also, the CL value is important and sets the value of the load caps. C12 and C13:

Ccap = CL * 2 - Cpin, where Cpin = 4 pF.

For a crystal with CL = 8 pF, the caps should be 12 pH each. For other CL values, adjust the cap value.

Also make sure you haven't mounted the crystal 90 degrees to the correct position.

RE: nRF52832 never appears on phone as an Adafruit Feather nRF52832

0miker0 — Mon, 23 Nov 2020 12:27:38 GMT

Over the weekend I've discovered that the four pin 32Mhz crystal had the pins incorrect when I created the footprint. After rotating the part 90 degrees, it works perfectly.

Would it be possible to cloie this case?

Thank you,

Mike