zephyr HCI UART on nRF52DK - HCI interface bring up fails

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

Håkon Alseth — Mon, 13 Aug 2018 06:29:30 GMT

Hi,

This thread is >1 year old. If you have an issue, please create a new case.

Håkon

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

icephyr — Sun, 12 Aug 2018 14:07:58 GMT

Hi，sundar，

I met the same problem with you,can tell me how this problem was solved?thanks

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

amartino — Mon, 16 Oct 2017 14:25:34 GMT

@Robin Could you please post the steps for a successful example? I'm trying to have them documented here. Didn't thought it would work with the JLink directly, which is why I initially started with the external UART connection.

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

sundar — Tue, 07 Feb 2017 08:58:07 GMT

Well I finally figured it out. It was a problem with the Raspberry Pi in my case. I could make it work with the UART interface with an x86 laptop running Linux. I believe it has something to do with the FTDI UART driver on the Pi. It worked occasionally and crashing the kernel in a while. So it has nothing to do with the UART interface being bridged by the USB CDC ttyACMx interface. Thanks for the help and timely responses from the community!

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

robin — Fri, 03 Feb 2017 19:33:54 GMT

I am also working though this problem: moving the UART connection from the Segger JLink-based VCP to PCA10040 header pins. A photo of my setup is at drive.google.com/open A photo of the UART GPIO pins: drive.google.com/open A photo of the SBxx to be cut: drive.google.com/open I have been working on the for a couple days and believe it too is related to HW flow control: RTS/CTS lines are at issue.

As a related point, I have been successful in getting the HCI-H4 to work when I interconnect the Raspberry Pi with the PCA10040 via the Segger JLink VCP. see screenshot drive.google.com/open

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

sundar — Fri, 03 Feb 2017 14:47:57 GMT

The Linux host has two controllers and I have brought down hci0 (the on-board interface) before the experiments. I don't have a logic analyser with me so I'd have to consider the LED blink option or the RTT method. I'm hoping to configure the RTT support and debug using the JLink debugger. I'll try and update.

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

Carles — Fri, 03 Feb 2017 14:27:52 GMT

Weird indeed. That said in your ttyUSBx log I see you have 2 controllers connected, maybe we could start by removing one of them. Also I'm not sure who's sending that Reset command, seems strange that btmgmt would do that at that point in time. The only option I can see right now is to sniff the GPIO pins with a logic analyzer to see whether the reset command is reaching the nRF52. Or you could also try to modify the code in hci_uart so that every time it receives a packet it blinks an LED or something similar.

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

sundar — Fri, 03 Feb 2017 14:11:26 GMT

It appears as a /dev/ttyUSBx interface on Linux. The RTS from the nRF52DK is connected to the CTS pin in the FTDI module and vice versa for the board's CTS pin. It does not seem to be an issue with flow control because the other HCI commands and events are getting transferred. If the RTS/CTS pins are not connected the static-addr command would fail and BTMON wouldn't show the capabilities info upon init.

Only the HCI reset command is not getting processed. Weird.

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

Carles — Fri, 03 Feb 2017 13:13:21 GMT

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?

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

sundar — Fri, 03 Feb 2017 12:35:44 GMT

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

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

Carles — Fri, 03 Feb 2017 11:34:57 GMT

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

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

sundar — Thu, 02 Feb 2017 15:58:59 GMT

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.

RE: zephyr HCI UART on nRF52DK - HCI interface bring up fails

Håkon Alseth — Mon, 30 Jan 2017 09:18:44 GMT

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