nRF51422 radio issues

RE: nRF51422 radio issues

Adrian Lita — Thu, 20 Jul 2017 13:43:15 GMT

Thank you for the support. After long hours of debugging, I managed to find the problem. When I designed the board, I've put a certain 16MHz oscillator, but when I had to order, I found that wasn't in stock at that time, so I ordered another one with the same footprint. Unfortunately, the load capacitance was different. With the first one it was 16pF and with the second one it was 20pF.

I managed to see this when I touched the oscillator with my bare hands. Probably my skin acted like a capacitance between XL1/2 and GND, and that was the moment I've seen the board was seen by my phone/laptop.

RE: nRF51422 radio issues

Petter Myhre — Thu, 20 Jul 2017 10:50:39 GMT

You checked the software on the PCA10028 by blinking leds? Can you try to see if other parts of the application works as well? Mainly the Bluetooth communication, since this seems to be the issue on your custom board. I'm not familiar with PacketLogger from Apple devtools. A commercial sniffer trace with a Frontline or Ellisys sniffer is preffered, or you can use our nRF Sniffer tool for free.

RE: nRF51422 radio issues

Adrian Lita — Thu, 20 Jul 2017 10:00:02 GMT

One other comment I have is that I use a 16MHz crystal, but it's a bigger one, not as the one you use. The traces aren't more than 1cm long, and I have capacitors and everything.

RE: nRF51422 radio issues

Adrian Lita — Thu, 20 Jul 2017 09:59:09 GMT

Also, I've build another board, on which I am pretty sure there isn't any soldering issues. The behaviour is the same.

RE: nRF51422 radio issues

Adrian Lita — Thu, 20 Jul 2017 09:58:03 GMT

I installed PacketLogger from Apple devtools, and I see the device at some moment, and this is what it outputs: LE Meta Event - LE Advertising Report - 1 - FC:F6:4D:27:37:7E -45 dBm Parameter Length: 27 (0x1B) LE Advertising Report Num_Reports: 0X01 Event_Type: Connectable undirected advertising (ADV_IND) Address_Type: Random Device Address Peer_Address: FC:F6:4D:27:37:7E Length_Data: 0X0F Appearance: 000000 Flags: 0x06 Local Name: Thingy Data: 03 19 00 00 02 01 06 07 09 54 68 69 6E 67 79 RSSI: -45 dBm

RE: nRF51422 radio issues

Adrian Lita — Thu, 20 Jul 2017 09:27:10 GMT

Yes, the app was developed on PCA10028, and I only use 3 IOs, which I checked and the software is running (LEDs are toggling). Can you please tell me how I upload sniffer trace?

RE: nRF51422 radio issues

Petter Myhre — Thu, 20 Jul 2017 08:29:29 GMT

Have you checked that your application is running properly on a board you know works? Like one of our DKs? Could you upload sniffer trace?

RE: nRF51422 radio issues

Adrian Lita — Wed, 19 Jul 2017 13:46:35 GMT

Update: I use nRF Connect on my iPhone, and I sometimes see the device, has -47 dB (which I presume is very good), but can't connect to it. Also it disappears, and then reappears, but is not connectable.

Can you please give me some hints on what to check on this ?

RE: nRF51422 radio issues

Adrian Lita — Wed, 19 Jul 2017 13:46:16 GMT

Can you please give me some hints on what to check on this ?

Kind regards, Adrian