MPSL ASSERT: 1, 1310

[HauJohn]

I encountered the error MPSL ASSERT: 1, 1310 when establishing a BLE connection on my custom board, only happens when using an external 32 kHZ crystal oscillator (

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL). Could you provide information on what issue this error might be related to? 

I am using nRF Connect SDK v2.9.1. My custom board is based on the nRF54L15.

[Kenneth]

Hello,

Try to change CONFIG_MPSL_HFCLK_LATENCY=1500

Kenneth

[HauJohn]

Hi, your method works. I also tried another approach by configuring the internal capacitor for the HFXO. With values from 4000 to 10750, the issue no longer occurs. However, specifically with the value 10500, the device encounters the same error immediately during advertising.

From what I read, increasing MPSL_HFCLK_LATENCY impacts power consumption.

Could you clarify the relationship between MPSL_HFCLK_LATENCY and the HFXO internal capacitor configuration as described above? Which approach would be the most appropriate to resolve the issue?.

[Kenneth]

HauJohn said:

MPSL_HFCLK_LATENCY

Use this one yes.

HauJohn said:

HFXO internal capacitor configuration

You should only configure this parameter during radio_test to ensure the carrier is as close as possible to the configured frequency when you are outputting a continuous carrier. For instance if you setup a carrier on channel 2, then use a spectrum analyzer and check which setting that get you closest to frequency 2402MHz. This parameter can also indirectly affect the startup time, but with wrong setting you can be off frequency (e.g. out of spec). The carrier should for a BLE device be maximum +-96kHz off center frequency (+-40ppm at 2.4GHz).

Kenneth

[HauJohn]

As I understand, the most accurate method is to use a spectrum analyzer through a radio test to precisely determine the required capacitor value for stable radio clock operation. Increasing MPSL_HFCLK_LATENCY is only a workaround, correct?

Could you explain in detail what aspects are affected by increasing MPSL_HFCLK_LATENCY? For example, does it impact data transmission speed, power consumption during data transfer, etc.

[Kenneth]

Hi,

This is directly related to the settling time of the HFXO, in nRF Connect SDK v2.9.x it simply was configured to short.

Kenneth

[HauJohn]

I just want to clearly understand what the parameter CONFIG_MPSL_HFCLK_LATENCY means. Is it the ramp-up time during packet transmission and reception as shown in this diagram?

If that’s the case, then increasing this parameter could reduce the transmission speed, right?

[Kenneth]

No, it's telling the software how far ahead of the BLE event that it should startup the HFCLK.

Kenneth