Recommended SoftDevice-Clock-Configuration using RC

[AlwinG]

Is there any documentation about how to configure the SoftDevice clock configuration using the RC as SoftDevice clock source?

My target is the nRF52832 with the S132 Softdevice and no external 32kHz crystall.

I configured the Softdevice with following settings:

NRF_SDH_CLOCK_LF_SRC = NRF_CLOCK_LF_SRC_RC
NRF_SDH_CLOCK_LF_RC_CTIV = 12
NRF_SDH_CLOCK_LF_RC_TEMP_CTIV = 2
NRF_SDH_CLOCK_LF_ACCURACY = NRF_CLOCK_LF_ACCURACY_20_PPM

The nRF works as peripheral and keeps connected in Low-Power mode with a central.

The above listed configuration worked but now on a single target (same HW, same FW) I receive a disconnect event after some minutes with the reason BLE_HCI_CONNECTION_TIMEOUT (0x08)!

Now I wanted to search documentation to check if my settings are correct.

Has someone an answer?

[Simon]

I think the problem is that you have too high accuracy. As mentioned in this answer, a high accuracy will lead to a smaller receive window and you will be more likely to miss packets. Due to this errata you should set the accuracy to 500ppm. Otherwise, the recommended configuration is to set  NRF_SDH_CLOCK_LF_RC_CTIV  equal 16 (No need to calibrate more often than necessary since it will consume more power) and NRF_SDH_CLOCK_LF_RC_TEMP_CTIV  equal to 2.

Best regards,

Simon