How to detect if BLE is transmitting or not.?

[Pratik_BMek]

Hello there,

We are using nRF52832 custom board. I2C and GPIO are working on it. Then I uploaded BLE program (which is tested on nRF52-DK) but BLE is not showing up at all. We are using PCB-printed antenna of length 22.0241 mm. Recommended length is around 23 mm, can this be a root cause of the issue. I calculated the frequency theoretically from nRF Antenna Design manual, it is around 2.35 GHz. (Dielectric constant of the material is same as in document)

Now, How can detect if this antenna is transmitting at some different frequency or not transmitting at all? We don't have a spectrum analyzer.

Is there any method, any status registers etc which I can try to read so that I can confirm if it is transmitting or not.?

After this, I will be able to decide if antenna length is the issue or some other issue is there.

FYI, we are using internal crystal. External crystal is not connected.

Thanks in advance,

[Daniel Wang]

you are using internal 32 kHz clock when starting the softdevice?

#define NRF_CLOCK_LFCLKSRC {.source = NRF_CLOCK_LF_SRC_RC, \ .rc_ctiv = 16, \ .rc_temp_ctiv = 0}
nrf_clock_lf_cfg_t clock_lf_cfg = NRF_CLOCK_LFCLKSRC;
SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL);

and you have a external 32 MHz crystal on your board?

[Pratik_BMek]

Thanks for the response Daniel. We had 32MHz crystal on board but we have removed it as they consider it default if it is there. So now we have just removed it, we DO NOT have it on board. However, we haven't changed anything in the program for using internal crystal.

[Jørn]

Hello Pratik_BMek

The 32 MHz crystal is required for radio operation, and must be present if you are to use the radio. For BLE the 32 MHz crystal must have a maximum frequency tolerance of +/- 40ppm.

Best regards

Jørn Frøysa

[Pratik_BMek]

Thanks for the answer Jorn, we are soon to try with the xtal. Will update results here. Tolerance point is noted. Thanks,

[Pratik_BMek]

@Jørn Frøysa It will help if you can provide a link to any document that says why we can't use internal crystal.? I am just curious about the reason because our is completely dead. If the external crystal improves the performance then antenna should give something at least some weak signal, that's what we thought.
Thanks,