Balena Fin v1.1 BLE 4.2 Data Length Extension?

balenaFin
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#1

I am trying to use DLE (Data Length Extension) to increase the throughput of connections to sensors attached over BLE. This feature was introduced in the 4.2 bluetooth spec that is supposed to be supported by the Fin.

My custom application sends commands directly to the HCI device since DLE and other newer features are not yet supported by Bluez. I have successfully used DLE on a Raspberry Pi 3B+, but on the Fin I get an “Unknown HCI Command” response, which is consistent with a 4.1 or earlier device.

I tracked down the module used on the v1.1 Fin, but am having a hard time finding documentation on the actual chipset being used in the module.

I’ve come up with three potential solutions, but they depend on more information:

  1. Is there newer firmware that can be loaded onto the HCI device that would support DLE? I don’t know the chip model, so I can’t track this down.
  2. Is there a newer alternate module (with DLE support) that I could have placed on a custom batch of Fins?
  3. USB dongle… I would prefer not to use a USB dongle because many of them do not have an external antenna (which my application requires) among other reasons.

TL;DR:

  • Can someone provide a model number for the bluetooth chip being used, so I can track down documentation and firmware?
  • And is there an alternate module I could have put on the Fin that supports newer BLE features?
#5

@aferm Thanks for getting in touch. I’ve reached out to my colleagues who work on the Fin, and should be able to give some answers / guidance here. We’ll be in touch soon

#7

Hi @aferm as documented in the schematics, the module used is Tayo Yuden WYSBHVGXG which relies on the Marvell 88W8887 chip. As you can see from the official NXP page ( NXP recently acquired Marvell WiFi and BT division and portfolio) it has even been updated to BT 5.0 lately (still waiting for firmware that enables that on linux). balenaOS 2.71 does ship the latest firmware and driver available which is as recent as February 2021.

#8

sorry, here is the NXP product page 88W8887: 1x1 Dual-band Wi-Fi® 5 (802.11ac) and Bluetooth®5.0 Combo Solution | NXP Semiconductors

#9

Unfortunately, I am limited to only being able to see the overview on the page you linked, even after signing into my NXP account.

We are in the process of upgrading or devices from Balena OS 2.58.3 to 2.72, but the upgraded devices still give me the same response to the HCI command. Is the firmware loaded on boot, or do I need to manually invoke an upgrade?

#10

Hello @aferm ,

The firmware should be loaded on boot. I’ve reached out to the module manufacturer to see if we can share the datasheet, as I’m not sure we’re allowed to do so.

Also, can you paste the output of btmon? You might need to change the debug level.

Cheers,
Nico.

#13

Hey @aferm.

Have you had any success obtaining the output of btmon as the colleague suggested?