Re: Zephyr hci_usb nrf52840

Carles Cufi

Hi Nathan,


In order to be able to ascertain if the problem is in the USB transport layer (which could be since it’s relatively new and untested) could you please try instead to use the hci_uart application, assuming you are using our nRF52840 development kit, so that we see if the problem disappears when using a UART transport instead of an USB one.


You can find instructions on how to do so here:






From: users@... <users@...> On Behalf Of nathan.miller@...
Sent: 02 May 2018 00:11
To: users@...
Subject: [Zephyr-users] Zephyr hci_usb nrf52840


Hi all,

I am trying to test an nRF52840 as a USB HCI using the Zephyr hci_usb sample project. I'm running into an issue in which devices I attempt to connect to will disconnect themselves after about 30 seconds, every time I attempt to connect. When I watch btmon, I see this:

< ACL Data TX: Handle 0 flags 0x00 dlen 7                  #15 [hci0] 17.698158
      ATT: Exchange MTU Request (0x02) len 2
        Client RX MTU: 517
< HCI Command: Disconnect (0x01|0x0006) plen 3             #16 [hci0] 49.737234
        Handle: 0
        Reason: Remote User Terminated Connection (0x13)

it appears that the device never receives or never responds to the Exchange MTU Request. I'm using bluetoothctl to establish the connection. I've tried two different device types and both exhibit the problem, and when I attempt to use the internal adapter on my host, I do not have this problem with either device. My host is an x86_64 machine running Ubuntu 16.04.4, kernel version 4.13.0-39, and BlueZ version 5.49. I've attempted it with both a Nordic PCA10056 board and a Rigado BMD-340 dev board. Has anyone seen this before? I'm not entirely sure what steps to take next to debug this. I can provide any additional info necessary.

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