Custom PCB: no BLE

[Dieter]

Hello,

I've got the PCA10040 dev kit and it works fine. To match my PCB setup I've cut SB2, this disables the 32kHz osc.

For debugging purposes I went back to the examples of SDK 15.0.0 and loaded the ble_app_blinky.

I modified sdk_config.h:

NRF_SDH_CLOCK_LF_SRC -> 0 use RC oscillator

NRF_SDH_CLOCK_LF_CTIV -> 16

NRF_SDH_CLOCK_LF_TEMP_CTIV -> 2

I also enabled the RTT, so I get debug messages.

This works fine on the PCA10040 board, but not on my custom PCB which uses exactly the  same nRF52832xxAA.

Relevant hardware differences between the dev kit and my PCB:

- no 32kHz osc (hence the cut in SB2)

- no DC/DC inductors on DCC, but this appears to be unused in the ble_app_blinky (DCDCEN is 0).

- chip antenna

Using nRF Connect I can see the dev kit but not my custom PCB. I just get "app: Blinky example started"

I've got the other part of the code running: I can use GPIOs, peripherals etc so my debugger and IDE work correct.

Did I miss something obvious?

Should I use a different example to troubleshoot?

[Nguyen Hoan Hoang]

First thing I would check in this case your 32MHz crystal.  Make sure that it work.  To check that, just enable it in the code, if it hangs then your oscillator is not working hence no RF signal.  Second thing was it solder in the correct position and reversed ?  Even if the RF section was not fully tuned, you should see something with very weak RSSI.  

[Dieter]

Hi Nguyen,

just to follow up: The 32MHz crystal was ok, the configuration too. The PCB layout is unusable. I've sent a board for RF-analysis (I don't have the tools here) and got some instructions how to disable the on board chip antenna.

I soldered a 29mm wire to the pad and it works! (a coax cable and wifi antenna from an old router works too)

...but not on my Huawei P20 lite. Should someone else have this phone, I can't recommend it as for some reason it does not see my board. The old Samsung S III mini works just fine, even with the wire as antenna. I'll use that :-)

Meanwhile I've got all my boards running with bluetooth.

Thanks!