The reasons for BLE_HCI_INSTANT_PASSED occurring on a peripheral and the corresponding countermeasures.

[keigo.imaizumi]

I using XIAO nrf52840.
https://wiki.seeedstudio.com/XIAO_BLE/

I am developing a BLE peripheral device using the nRF52840.
This device is designed to connect with a specific central device.
The peripheral detects disconnect events, which can be attributed to two main factors:

• BLE_HCI_CONNECTION_TIMEOUT
• BLE_HCI_INSTANT_PASSED

For BLE_HCI_CONNECTION_TIMEOUT, I believe the cause is the distance between the BLE devices or the presence of many 2.4 GHz frequency devices in the area.
If this issue occurs frequently, I am considering advising users to reduce the distance between the devices.

As for BLE_HCI_INSTANT_PASSED, what would be the best approach to handle this issue?

I looked at https://devzone.nordicsemi.com/f/nordic-q-a/67703/ble_hci_instant_passed-disconnection-reason.
but I’m still not entirely sure I understand it.
Does it mean that the LFCLK source settings are incorrect?
I'll include the sdk_config settings below.

//==========================================================

// <h> Clock - SoftDevice clock configuration

//==========================================================

// <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 1

#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 0

#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 0

#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 7

#endif

thank you for reading my question.

[Simonr]

Hi

Try setting the oscillator settings to the following since I think the XIAO you're using doesn't have an external 32.768 kHz crystal oscillator, so you'll have to use the internal RC oscillator.

// <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

[keigo.imaizumi]

Hello Simonr 

First of all, thank you for your reply.

I’m planning to adjust the SoftDevice clock settings and observe how it goes.

Regarding the BLE_HCI_INSTANT_PASSED error, do you think it’s related to the clock settings?
I’d like to understand this better, so if possible, could you explain the nature of this error?