• State Verified Answer
  • Replies 13 replies
  • Subscribers 63 subscribers
  • Views 11762 views
  • Users 0 members are here
Attachments (0)
Nordic Case Info
  • Case ID: 119294
Options
This post is older than 2 years and might not be relevant anymore
More Info: Consider searching for newer posts

zephyr HCI UART on nRF52DK - HCI interface bring up fails

sundar

Hi,

I am not sure if this is the right place to open up a thread about a zephyr HCI firmware issue. Since Nordic also contributes to zephyr I'm putting up this question here.

I have compiled the hci_uart sample from zephyr and flashed zephyr.hex to my nRF52DK board via JLINK. I connected the UART pins (TX, RX, RTS and CTS) to an FTDI USB-UART converter plugged to a Raspberry Pi 3 running Linux (Raspbian) and tries to enumerate with hciattach.

Here's what I did:

#sudo hciattach -s 115200 ttyUSB0 any 115200 flow Device setup complete

#sudo hciconfig hci1 hci1: Type: BR/EDR Bus: UART BD Address: 00:00:00:00:00:00 ACL MTU: 27:7 SCO MTU: 0:0 DOWN RX bytes:224 acl:0 sco:0 events:15 errors:0 TX bytes:76 acl:0 sco:0 commands:15 errors:0

#sudo hciconfig hci1 up Can't init device hci1: Cannot assign requested address (99)

What I tried so far:

  • Reset the nRF52DK before performing the HCI attach as well but it's not helping
  • All the pins - Ensured TX, RX, RTS and CTS are connected correctly
  • Tried assigning a BDADDR by
    passing an address to hciattach but
    doesn't help
  • Configured 115200 as the baud rate in the zephyr kernel configuration and by default flow control is enabled
  • Turning off/on the flow control from hciattach doesn't help either

I am not sure what's going wrong but there seems to be no communication happening between the nRF52DK and the Host (R-Pi3).

Any help would be appreciated.

  • 0

    Hi,

    Did you compile hci_uart from master, or did you check out a given version?

    It may be that your bluez installation is a bit old. Have you tried following the guide by Carles?

    Note, if your kernel version is older (f.ex. 4.4.x), you may have to configure bluez with --enable-experimental for bluez to compile <bluezsrc>/tools/btattach

    Be sure to use btmon for monitoring and logging to see if the communication is up and running properly. This command should be called prior to btattach.

    Cheers, Håkon

  • 0 in reply to Håkon Alseth

    Thanks for the link to the guide. I was able to get the HCI UART sample working as explained in it. I was under the impression that I had to connect via the UART pins (exposed via GPIO 5, 6, 7, 8). I could only bring up the interface with the ttyACM0 interface created via the USB CDC interface. I read somewhere on the zephyr wiki page that the ttyACM0 interface is bridged to the nRF52's UART interface.

    I want to be able to run the board with battery. I tried to attach with the UART interface (through an FTDI UART converter with proper flow control pins connected) and I was able to set the BD address with the static-addr command on btmgmt but when auto-power command seems to fail. Only if I use the ttyACM0 interface was I able to power on with auto-power command.

    I am wondering if the bridging somehow affects the usage of plain UART pins. Is there a way to un-bridge this via software or jumper pins? Is it possible to talk to the nRF52 through the UART interface directly?

    Thanks.

  • 0 in reply to Håkon Alseth

    I am told by the hardware people that if you want to use the UART without powering the board via USB, then the safest option is to configure the UART pins to some other GPIOs that are not taken by the Segger IC (any free GPIOs, you can then change the config in the boards/ folder in Zephyr) and then you should be able to run on battery with the UART interfacing the remote Host.

    Here are the lines you should change once you've chose new pins:

    github.com/.../Kconfig.defconfig

    Suggested pins for you to use: P0.28-P0.31

  • 0 in reply to Håkon Alseth

    Hi Carles,

    I tried your suggestion of using pins P.028 - P.031 and I see the same issue. When comparing the BTMON logs for both interfaces I see there is no response for the HCI reset command for the auto-power command from btmgmt in UART interface case. If ttyACMx interface is used, the HCI reset happens and we get a HCI event for reset completion.

    Here are the logs for both interfaces: http://pastebin.com/zvY0nyCf (UART interface) http://pastebin.com/dQUGAzQT (ttyACMx interface)

    I'm checking how the reset is handled on zephyr now. Please let me know if you have any pointers.

    Thanks, Sundar

  • 0 in reply to Håkon Alseth

    How does exactly the "UART interface" appear to Linux when you are using FTDI? is it a UART device in dev/tty* ? Perhaps it's an issue with flow control? have you mapped the CTS and RTS lines correctly?

Related