Bluetooth Module, BT840F, based upon nRF52840 doesn't seem to advertise.

I am using Fanstel's BT840F BLE module which is based upon nRF52840 for my application. I am using PCA10056 DK to program it. I tried to program the BLE module on the DK with ble_app_beacon example and it successfully shows itself in the nRF Connect Android app as "nRF Beacon". I tried to program the BT840F module using the DK and the same example was successfully programmed but when I connect it to the external 3.7 volt battery, nothing shows up in nRF Connect app. I made sure the connections are fine and the VDD pin on the chip actually has 3.7 volts going in it. What might be the reason for why it is not advertising in the similar manner to the Bluetooth module on the DK?

0 Simonr over 4 years ago

I tried to program the BLE module on the DK with ble_app_beacon example and it successfully shows itself in the nRF Connect Android app as "nRF Beacon".

I assume this was the DK itself you programmed with the BLE app beacon? Please note that the nRF52840 should only be powered by 1.7-3.6V. I assume you power it with high voltage mode operating voltage, where the typical voltage is 3.7V.

The most common issue with third party modules is that they don't have the external LF crystal which all our SDK examples use by default. Please try changing the following configs in the projects sdk_config.h header file to these values, as that is likely to fix your issue.

//==========================================================
// <o> NRF_SDH_CLOCK_LF_SRC  - SoftDevice clock source.
 
// <0=> NRF_CLOCK_LF_SRC_RC 
// <1=> NRF_CLOCK_LF_SRC_XTAL 
// <2=> NRF_CLOCK_LF_SRC_SYNTH 

#ifndef NRF_SDH_CLOCK_LF_SRC
#define NRF_SDH_CLOCK_LF_SRC 0
#endif

// <o> NRF_SDH_CLOCK_LF_RC_CTIV - SoftDevice calibration timer interval. 
#ifndef NRF_SDH_CLOCK_LF_RC_CTIV
#define NRF_SDH_CLOCK_LF_RC_CTIV 16
#endif

// <o> NRF_SDH_CLOCK_LF_RC_TEMP_CTIV - SoftDevice calibration timer interval under constant temperature. 
// <i> How often (in number of calibration intervals) the RC oscillator shall be calibrated
// <i>  if the temperature has not changed.

#ifndef NRF_SDH_CLOCK_LF_RC_TEMP_CTIV
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
#endif

// <o> NRF_SDH_CLOCK_LF_ACCURACY  - External clock accuracy used in the LL to compute timing.
 
// <0=> NRF_CLOCK_LF_ACCURACY_250_PPM 
// <1=> NRF_CLOCK_LF_ACCURACY_500_PPM 
// <2=> NRF_CLOCK_LF_ACCURACY_150_PPM 
// <3=> NRF_CLOCK_LF_ACCURACY_100_PPM 
// <4=> NRF_CLOCK_LF_ACCURACY_75_PPM 
// <5=> NRF_CLOCK_LF_ACCURACY_50_PPM 
// <6=> NRF_CLOCK_LF_ACCURACY_30_PPM 
// <7=> NRF_CLOCK_LF_ACCURACY_20_PPM 
// <8=> NRF_CLOCK_LF_ACCURACY_10_PPM 
// <9=> NRF_CLOCK_LF_ACCURACY_5_PPM 
// <10=> NRF_CLOCK_LF_ACCURACY_2_PPM 
// <11=> NRF_CLOCK_LF_ACCURACY_1_PPM 

#ifndef NRF_SDH_CLOCK_LF_ACCURACY
#define NRF_SDH_CLOCK_LF_ACCURACY 1
#endif

Best regards,

Simon