Zephyr device tree BLE NUS in nRF52832

Hello,

I am trying to have a BLE NUS connection between an F9P and my phone (central) via an nRF52832 (peripheral). I am trying to get a minimal code based on the corresponding XPLR example to run but believe I am running into some device tree issues (which I see from previous reported issues to be a headache source 😅).

My understanding is that seeing that the code I'm implementing is flashed to the nRF52832, my overlay should contain the open-cpu tag. What's more, in order to be in accordance with the Zephyr philosophy, I should rely on

errorCode = uDeviceOpen(NULL, &gDeviceHandle);

as opposed to

uDeviceGetDefaults(U_DEVICE_TYPE_SHORT_RANGE_OPEN_CPU, &gDeviceCfg);
errorCode = uDeviceOpen(&gDeviceCfg, &gDeviceHandle);

though whatever I do I can't seem to get past an U_ERROR_COMMON_NOT_INITIALISED errorCode.

My overlay file is as follows:

 / {
    cfg-device-short-range {
        compatible = "u-blox,ubxlib-device-short-range";
        status = "okay";
        module-type = "U_SHORT_RANGE_MODULE_TYPE_INTERNAL";
        open-cpu;
        network = <&label_cfg_network_ble_peripheral>;
       };

    label_cfg_network_ble_peripheral: cfg-network-ble-peripheral {
        compatible = "u-blox,ubxlib-network-ble";
        status = "okay";
        role = "U_BLE_CFG_ROLE_PERIPHERAL";
    };
};

My main.c can be found here and my prj.conf here.

Via the debugger (I'm using an nRF52 DK), I've narrowed down the bringing up of the network failure to be from the device instance pointer saying the context pointer is 0x0 <nvs_flash_al_wrt>. Am I missing something obvious here? Apologies if it is trivial, it is my first experience with nRF/Zephyr.

Many thanks in advance for your help!

P.S.: development environment is VS Code + nRF Connect for VS Code v2024.3.25 + nRF toolchain v2.5.0 and ubxlib v1.4.0

Thanks for posting and sorry you're having trouble with this.

Do you have the debug log output from ubxlib, as far as it gets, when this is run? I ask because, when it processes the device configuration it picks up from the device tree, it prints out a line beginning with U_PORT_BOARD_CFG which tells you what it has done.

Thing is, though, the error code U_ERROR_COMMON_NOT_INITIALISED sounds like it isn't even getting that far. If this is the error code returned by uDeviceOpen(), it seems more likely that you are missing a conditional compilation flag somehow.

Could you post the output from a clean build so that we can see which files are being pulled in? Specifically, it would good to see the line "UBXLIB_FEATURES will be...".

Hi Rob,

Thanks for your comments and help. I should have been more explicit in my initial message, the U_ERROR_COMMON_NOT_INITIALISED is raised by the uNetworkInterfaceUp call, not the uDeviceOpen one; apologies for that!

Here is the output of a pristine build, which shows gnss and short_range features (just like I intended via a local environment variable):

 *  Executing task: nRF Connect: Build [pristine]: ubxlib_ble/build (active) 

Building ubxlib_ble
west build --build-dir /home/mleroy/Documents/nrf_projects/ubxlib_ble/build /home/mleroy/Documents/nrf_projects/ubxlib_ble --pristine --board nrf52dk_nrf52832 --no-sysbuild -- -DNCS_TOOLCHAIN_VERSION=NONE -DCACHED_CONF_FILE=/home/mleroy/Documents/nrf_projects/ubxlib_ble/ubxlib/port/platform/zephyr/default.conf;/home/mleroy/Documents/nrf_projects/ubxlib_ble/prj.conf -DDTC_OVERLAY_FILE=/home/mleroy/Documents/nrf_projects/ubxlib_ble/nrf52dk_nrf52832.overlay

-- west build: generating a build system
Loading Zephyr default modules (Zephyr base).
-- Application: /home/mleroy/Documents/nrf_projects/ubxlib_ble
-- CMake version: 3.20.5
-- Found Python3: /home/mleroy/ncs/toolchains/7795df4459/usr/local/bin/python3.8 (found suitable version "3.8.2", minimum required is "3.8") found components: Interpreter 
-- Cache files will be written to: /home/mleroy/.cache/zephyr
-- Zephyr version: 3.4.99 (/home/mleroy/ncs/v2.5.0/zephyr)
-- Found west (found suitable version "1.1.0", minimum required is "0.14.0")
-- Board: nrf52dk_nrf52832
-- Found host-tools: zephyr 0.16.1 (/home/mleroy/ncs/toolchains/7795df4459/opt/zephyr-sdk)
-- Found toolchain: zephyr 0.16.1 (/home/mleroy/ncs/toolchains/7795df4459/opt/zephyr-sdk)
-- Found Dtc: /home/mleroy/ncs/toolchains/7795df4459/usr/bin/dtc (found suitable version "1.4.7", minimum required is "1.4.6") 
-- Found BOARD.dts: /home/mleroy/ncs/v2.5.0/zephyr/boards/arm/nrf52dk_nrf52832/nrf52dk_nrf52832.dts
-- Found devicetree overlay: /home/mleroy/Documents/nrf_projects/ubxlib_ble/nrf52dk_nrf52832.overlay
-- Generated zephyr.dts: /home/mleroy/Documents/nrf_projects/ubxlib_ble/build/zephyr/zephyr.dts
-- Generated devicetree_generated.h: /home/mleroy/Documents/nrf_projects/ubxlib_ble/build/zephyr/include/generated/devicetree_generated.h
-- Including generated dts.cmake file: /home/mleroy/Documents/nrf_projects/ubxlib_ble/build/zephyr/dts.cmake
Parsing /home/mleroy/ncs/v2.5.0/zephyr/Kconfig
Loaded configuration '/home/mleroy/ncs/v2.5.0/zephyr/boards/arm/nrf52dk_nrf52832/nrf52dk_nrf52832_defconfig'
Merged configuration '/home/mleroy/Documents/nrf_projects/ubxlib_ble/ubxlib/port/platform/zephyr/default.conf'
Merged configuration '/home/mleroy/Documents/nrf_projects/ubxlib_ble/prj.conf'
Configuration saved to '/home/mleroy/Documents/nrf_projects/ubxlib_ble/build/zephyr/.config'
Kconfig header saved to '/home/mleroy/Documents/nrf_projects/ubxlib_ble/build/zephyr/include/generated/autoconf.h'
-- Found GnuLd: /home/mleroy/ncs/toolchains/7795df4459/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd (found version "2.38") 
-- The C compiler identification is GNU 12.2.0
-- The CXX compiler identification is GNU 12.2.0
-- The ASM compiler identification is GNU
-- Found assembler: /home/mleroy/ncs/toolchains/7795df4459/opt/zephyr-sdk/arm-zephyr-eabi/bin/arm-zephyr-eabi-gcc
UBXLIB_FEATURES will be "gnss;short_range"
CMake Warning at /home/mleroy/ncs/v2.5.0/zephyr/CMakeLists.txt:1958 (message):
  __ASSERT() statements are globally ENABLED

-- Configuring done
-- Generating done
-- Build files have been written to: /home/mleroy/Documents/nrf_projects/ubxlib_ble/build
-- west build: building application
[1/360] Preparing syscall dependency handling

[3/360] Generating include/generated/version.h
-- Zephyr version: 3.4.99 (/home/mleroy/ncs/v2.5.0/zephyr), build: v3.4.99-ncs1
[143/360] Building C object CMakeFiles/app.dir/ubxlib/port/platform/zephyr/src/u_port_board_cfg.c.obj
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:837:26: warning: 'gpDeviceCfgWifiNetworkListApIpAddress' defined but not used [-Wunused-const-variable=]
  837 | static const char *const gpDeviceCfgWifiNetworkListApIpAddress[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:826:26: warning: 'gpDeviceCfgWifiNetworkListApPassPhrase' defined but not used [-Wunused-const-variable=]
  826 | static const char *const gpDeviceCfgWifiNetworkListApPassPhrase[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:815:22: warning: 'gDeviceCfgWifiNetworkListApAuthentication' defined but not used [-Wunused-const-variable=]
  815 | static const int32_t gDeviceCfgWifiNetworkListApAuthentication[][2] = {
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:804:26: warning: 'gpDeviceCfgWifiNetworkListApSsid' defined but not used [-Wunused-const-variable=]
  804 | static const char *const gpDeviceCfgWifiNetworkListApSsid[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:793:26: warning: 'gpDeviceCfgWifiNetworkListMode' defined but not used [-Wunused-const-variable=]
  793 | static const char *const gpDeviceCfgWifiNetworkListMode[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:779:26: warning: 'gpDeviceCfgWifiNetworkListHostName' defined but not used [-Wunused-const-variable=]
  779 | static const char *const gpDeviceCfgWifiNetworkListHostName[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:768:26: warning: 'gpDeviceCfgWifiNetworkListPassPhrase' defined but not used [-Wunused-const-variable=]
  768 | static const char *const gpDeviceCfgWifiNetworkListPassPhrase[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:757:22: warning: 'gDeviceCfgWifiNetworkListAuthentication' defined but not used [-Wunused-const-variable=]
  757 | static const int32_t gDeviceCfgWifiNetworkListAuthentication[][2] = {
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../ubxlib/port/platform/zephyr/src/u_port_board_cfg.c:746:26: warning: 'gpDeviceCfgWifiNetworkListSsid' defined but not used [-Wunused-const-variable=]
  746 | static const char *const gpDeviceCfgWifiNetworkListSsid[][2] = {
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[360/360] Linking C executable zephyr/zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:      337480 B       512 KB     64.37%
             RAM:       55968 B        64 KB     85.40%
        IDT_LIST:          0 GB         2 KB      0.00%
 *  Terminal will be reused by tasks, press any key to close it.

In terms of console output, here it is when I comment the uPortLogOff call in the main.c I attached in my previous message:

*** Booting nRF Connect SDK v2.5.0 ***

Initiating the module...
U_PORT_BOARD_CFG: using SHORT-RANGE device "cfg-device-short-range" from the device tree, module-type 0, open-cpu.
Starting BLE...
U_PORT_BOARD_CFG: using BLE network configuration associated with SHORT-RANGE device "cfg-device-short-range" from the device tree, role 2.
* Failed to bring up the network: -2

Thanks again for your help!

Thanks for the swift response. Sorry about the warnings, we try to avoid conditional compilation flags inside ubxlib but it is very much the Zephyr way and so in this particular case we end up with a combinatorial nightmare. Anyway...

As you say, you have UBXLIB_FEATURES gnss and short_range, which seems right. The print from your main.c "Starting BLE..." is only emitted if uDeviceOpen() returned 0, so that's good.

However: the second parameter to uNetworkInterfaceUp() should be the network type, which in this case would be U_NETWORK_TYPE_BLE (as opposed to the other possibility for a Short Range module which would be Wifi); you are calling it with U_BLE_CFG_ROLE_PERIPHERAL instead, which will turn out to be a value of 2, which corresponds to network type U_NETWORK_TYPE_CELL; that will indeed come back as not initialised since you don't have cellular in your build...?

No worries for the warnings, I know how difficult it is to handle aiming to support everything everywhere 😅

My understanding is that I was passing a network type as the second parameter, as per networkCfg.type, which was defined as U_NETWORK_TYPE_BLE in line 139 of my main file above. U_BLE_CFG_ROLE_PERIPHERAL is in the role attribute of uNetworkCfgBle_t, not the type. This code was really just a stripped down version of the XPLR example, but with the device exclusively defined as a BLE peripheral.

Nevertheless, I've replaced the peripheral mention with a central one both in the main and overlay files (and the console properly showing now role 1), but the failure remains.

I think it is more likely that the error stems from the device tree enclosed in my original message, but the BLE binding seems to be simple enough and I based my overlay file on the NINA-B3 one, specifically the cfg-device-short-range-1 which seems to be a BLE+Wifi chip. Therefore, that's why I am having a hard time figuring out what is causing the failure...

Apologies, I was getting role and type mixed up, let me look again...

Sure, thank you for your prompt reply!

Side note, as I wrote my message above it made me think that I could try adding a dummy Wifi phandle, i.e. making the overlay file as follows:

 / {
    cfg-device-short-range {
        compatible = "u-blox,ubxlib-device-short-range";
        status = "okay";
        module-type = "U_SHORT_RANGE_MODULE_TYPE_INTERNAL";
        open-cpu;
        network = <&label_cfg_network_ble_peripheral &label_cfg_network_wifi_client_home>;
       };

    label_cfg_network_wifi_client_home: cfg_network_wifi_client_home {
        compatible = "u-blox,ubxlib-network-wifi";
        mode = "U_WIFI_MODE_NONE";  // valid according to https://github.com/u-blox/ubxlib/blob/v1.4.0/port/platform/zephyr/dts/bindings/u-blox%2Cubxlib-network-wifi.yaml#L36
    };

    label_cfg_network_ble_peripheral: cfg-network-ble-peripheral {
        compatible = "u-blox,ubxlib-network-ble";
        status = "okay";
        role = "U_BLE_CFG_ROLE_PERIPHERAL";
    };
};

and albeit the build warnings regarding the unused variables are gone, the failure remains.

Hi, I'm sorry but Ubxlib currently doesn't support any BLE Gatt operations for open-cpu (internal) mode. The only thing available for now is the U-blox service SPS. The example for the XPLR-IOT1 uses the BLE functionality of the connected Nina W15 and not the host Nora B1.

So I'm afraid the only option for you at this point is to implement this using the Zephyr apis. An example can be found here: https://github.com/junqingzou/Zephyr_NUS_Sample

BR /Peter Lerup

Oh that's a shame, I thought and hoped it could work... So be it, I'll try with an alternative. Thank you both for your help!

u-blox / ubxlib

Zephyr device tree BLE NUS in nRF52832 #227