nRF52 BLE app hangs on ble_stack_init()

RE: nRF52 BLE app hangs on ble_stack_init()

Einar Thorsrud — Mon, 28 Jan 2019 10:27:00 GMT

Hi,

The SoftDevice Handler library is used by most BLE example in SDK 15.2. Do you use it? If so you have to configure it to use the RC oscillator by setting NRF_SDH_CLOCK_LF_SRC to 0 (NRF_CLOCK_LF_SRC_RC) in the projects sdk_config.h. You should not have to do any other modifications.

RE: nRF52 BLE app hangs on ble_stack_init()

spaniel — Fri, 25 Jan 2019 23:16:02 GMT

I've poked around and found this in nrf_drv_clock.c

#if (CLOCK_CONFIG_LF_SRC == NRF_CLOCK_LFCLK_RC) && !defined(SOFTDEVICE_PRESENT)
#define CALIBRATION_SUPPORT 1
#else
#define CALIBRATION_SUPPORT 1 // ** This was 0, changed it to 1 to force calibration support. **
#endif

Changing this to 1 seems to have gotten everything up and running. I really don't know what the consequences of this action are fully yet. The if statement seems to suggest that if a softdevice is present (which it is) then I shouldn't use calibration support.... I really don't know why this worked, which is scary!

RE: nRF52 BLE app hangs on ble_stack_init()

Nguyen Hoan Hoang — Fri, 25 Jan 2019 22:03:23 GMT

That seems correct for setting the RC. You'll need to trace it out. There might be some places in your code that may bypass the RC settings.

RE: nRF52 BLE app hangs on ble_stack_init()

spaniel — Fri, 25 Jan 2019 21:45:00 GMT

thanks for the quick response. That does seem to be the root cause. To confirm that the crystal is the problem, I removed the LF crystal from the circuit on the Development board and was able to reproduce the problem.

I've done some interneting and found that the clock source can be changed to RC instead of XTAL for applications where there is no LF crystal. Here's a resource that seemed to lay it out fairly well: https://rigado.zendesk.com/hc/en-us/articles/225674668-Example-files-will-not-run-on-my-hardware-LF-Clock-Source-Selection

I followed those steps and rebuilt, but still having the same issue. Am I missing another step?

thanks!

RE: nRF52 BLE app hangs on ble_stack_init()

Nguyen Hoan Hoang — Fri, 25 Jan 2019 20:00:58 GMT

I think the 32KHz crystal is missing on your production board.