Migrating from nrf51 DK to custom module

[gaminn]

Hi, I wan to load ble_app_hrs_s110_pca10028 project example from SDK 8.10 to a module purchased on eBay:

www.ebay.com/.../111600483137

This module has nrf51822 qfaag2 (instead of nrf51422 on nrf 51 DK) and has no 32 khz crystal.

I assumed I need to make these changes since no 32 khz crystal is present on the module:

I modified nrf_drv_config.h:

#define CLOCK_CONFIG_LF_SRC             NRF_CLOCK_LF_SRC_RC
#define CLOCK_CONFIG_LF_RC_CAL_INTERVAL NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION

And I also modified ble_stack_init function in main.c:

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_250_PPM, NULL);

However, the application still doesn't run on the module. I can load it and debug it, but it seems that something goes wrong in

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_250_PPM, NULL);

as the debugger can't hit any breakpoint after the function.

On nrf51 DK the same code runs.

[Nguyen Hoan Hoang]

You need to call SOFTDEVICE_HANDLER_INIT with NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION. The other one is to use the crystal. I see on the photo that the device is marking QFAB which is the 128KB Flash version. So make sure you adjust the linker script to the right value.

[gaminn]

Thanks, NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION solved the problém. The device is QFAAG2 = 256 kB flash.

[RiZsho]

I had the same problem and this resolved the issue. May I ask, for what purpose is this RC oscillator used? Will it affect performance and functionality when exposed to different temperatures?

[Nguyen Hoan Hoang]

Yes it does, that is why there is the calibration parameter. It allows to period periodically recalibrate the oscillator. The effect on performance is minimal.