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

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

Simonr — Thu, 05 Sep 2024 08:00:16 GMT

BLE_HCI_INSTANT_PASSED means that an instant was passed, and could be due to the LF crystal clock not being tuned correctly so that the device misses the HCI instant due to the clock being off by too much to catch it. I'm not 100% sure this is the error, but it's a good first step at least, as this has been seen as the cause of this error message for this.

Best regards,

Simon

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

keigo.imaizumi — Tue, 03 Sep 2024 10:16:40 GMT

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?

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

Simonr — Tue, 03 Sep 2024 09:12:25 GMT

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