#nrf52840 #ble unstable connection #nrf52840 #ble

Randy Chou <rchou3@...>

Hi community,
I'm using nrf52840 on our own development board, I met one problem about abnormal disconnect.

  • environment:
[Central] use BLE nRF connect run on nRF52840_PCA10056 (Windows)
[Peripheral 1] Zephyr peripheral_hids sample application runs on nRF52840_PCA10056
[Peripheral 2] Zephyr peripheral_hids sample application runs on our EVB (nRF52840)
  • result:
[per 1] the connection keeps.
[per 2] abnormal disconnect while I move the central a bit far away from peripheral (< 1m).

  • experiment
  1.  move the central device close next to peripheral 2. it can keeps connection.
  2. change the connection interval from 30ms to 7.5ms/10ms/15ms, it can keeps connection
  3. use our own FW which uses SoftDevice as Bluetooth stack. The distance won't affect the connection.
I'm wondering is this issue related to frequency drift.
As my understanding, in SoftDevice, it will do the clock calibration automatically.
I only find one related configuration (CONFIG_CLOCK_CONTROL_NRF5_K32SRC_250PPM).
Does it also have same feature in Zephyr? 
or do you have other comment about this issue?


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