How to diagnose central connection timeout?

RE: How to diagnose central connection timeout?

Vidar Berg — Wed, 20 Nov 2024 07:34:45 GMT

I think the issue might be something else than excessive drift on the slow clock as you're getting the same results with both the LF RC and crystal oscillator. You could also try using the LF synth to confirm that clock drift isn't the cause.

Does the proximity of the devices seem to make any difference? Close proximity should help if the problem is related to a poor link budget. It might be worth creating a new private support ticket and request a hardware review. Be sure to upload the gerbers and schematics.

RE: How to diagnose central connection timeout?

jmp246 — Tue, 19 Nov 2024 22:09:46 GMT

I have tested with

Internal 500ms

Latency 30

Timeout 32000ms

nRF52840 dongle (Central) -> BLE121LR USB dongle (Peripheral) works
nRF5340 DK (Central) -> nRF52840 dongle (Peripheral) works
RAYTAC MDBT53-DB (MDBT53-1M dev board) (Central) -> nRF52840 dongle (Peripheral) works
RAYTAC MDBT53-DB using low frequency RC (MDBT53-1M dev board) (Central) -> nRF52840 dongle (Peripheral) works
Custom board (MDBT53-1M) using LF crystal times out.
Custom board (MDBT53-1M) using LF RC times out.

clock_skew with CONFIG_APP_ENABLE_HFXO=y

https://docs.nordicsemi.com/bundle/ncs-1.6.0/page/zephyr/samples/boards/nrf/clock_skew/README.html

MDBT53-DB (A)

MDBT53-DB (B)

Custom board (A)

Custom board (B)

Seems like there is a issue with my board but I'm unsure where to look.

RE: How to diagnose central connection timeout?

Vidar Berg — Mon, 18 Nov 2024 16:18:43 GMT

Hello,

Do you have access to check the disconnect reason reported by the legacy BLE121LR device as well? Either way, since you have a nRF52840 Dongle, I would suggest you try use it with the Bluetooth® Low Energy app in nRF Connect for Desktop to see if you experience the same connection issues if you connect to the BLE121LR and request a CI above 6 seconds.

Best regards,

Vidar