nRF5340 Dynamic Connection Event Length

[AKV]

Hi,

I need to use two or more different event lengths for different modes. The event length should be set based on the mode before establishing a connection. I found that sdc_hci_cmd_vs_event_length_set() can be used for this purpose.

To implement this, I added the header:

#include <sdc_hci_vs.h>

Then, I tried to use the function with the following code:

uint8_t err;
static sdc_hci_cmd_vs_event_length_set_t event_length_param;
event_length_param.event_length_us = 5000;

err = sdc_hci_cmd_vs_event_length_set(&event_length_param);
if (err)
    printk("Failed to set event length (err %d)\n", err);
else
    printk("Event length set to %u units\n", event_length_param.event_length_us);

However, I am unable to compile the project due to the following error:
"Undefined reference to sdc_hci_cmd_vs_event_length_set."

Could you help me understand why this error occurs? Are there additional header files or configurations required?

Can you please provide an example implementation to make integration easier?

[dejans]

Hi,

Is your application based on any of our samples?

Which NCS version do you use?

Can you provide complete error log?

Best regards,
Dejan

[AKV]

Hi,

dejans said:

Which NCS version do you use?

NCS version 2.6.1.

dejans said:

Is your application based on any of our samples?

No, Our custom board code. 

Please check the complete log.

Fullscreen log14032025.txt Download

 *  Executing task: nRF Connect: Build: C50T1_RideGrid_nRF5340/build (active) 

Building C50T1_RideGrid_nRF5340
C:\WINDOWS\system32\cmd.exe /d /s /c "west build --build-dir d:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build d:/NORDIC/Projects/C50T1_RideGrid_nRF5340"

[0/26] Performing build step for 'mcuboot_subimage'
ninja: no work to do.
[0/5] Performing build step for 'b0n_subimage'
ninja: no work to do.
[3/18] Building C object CMakeFiles/app.dir/src/main.c.obj
In file included from D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/custom_module/MeshConnection.h:2,
                 from D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:19:
D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/include/zephyr/random/rand32.h:13:2: warning: #warning "<zephyr/random/rand32.h> is deprecated, include <zephyr/random/random.h> instead" [-Wcpp]
   13 | #warning "<zephyr/random/rand32.h> is deprecated, include <zephyr/random/random.h> instead"
      |  ^~~~~~~
In file included from D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:26:
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/legacy_module/inc/fm_config.h:25:1: warning: multi-line comment [-Wcomment]
   25 | // #define FM_UUID_SERV_VAL \
      | ^
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/legacy_module/inc/fm_config.h:27:1: warning: multi-line comment [-Wcomment]
   27 | // #define FM_MESH_SERVICE_CHAR_UUID_VAL \
      | ^
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:86:6: warning: return type of 'main' is not 'int' [-Wmain]
   86 | void main(void)
      |      ^~~~
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c: In function 'main':
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:96:9: warning: implicit declaration of function 'buffer_init' [-Wimplicit-function-declaration]
   96 |         buffer_init();
      |         ^~~~~~~~~~~
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:99:9: warning: implicit declaration of function 'ridegrid_device_info_send' [-Wimplicit-function-declaration]
   99 |         ridegrid_device_info_send();
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~
[5/18] Linking C executable zephyr\zephyr_pre0.elf
FAILED: zephyr/zephyr_pre0.elf zephyr/zephyr_pre0.map D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/zephyr/zephyr_pre0.map 
cmd.exe /C "cd . && D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\zephyr-sdk\arm-zephyr-eabi\bin\arm-zephyr-eabi-gcc.exe  -gdwarf-4 @CMakeFiles\zephyr_pre0.rsp -o zephyr\zephyr_pre0.elf  && cmd.exe /C "cd /D D:\NORDIC\Projects\C50T1_RideGrid_nRF5340\build\zephyr && D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\bin\cmake.exe -E true""
d:/nordic/nrfconnectsdk/toolchains/cf2149caf2/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: app/libapp.a(main.c.obj): in function `main':
D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:106: undefined reference to `sdc_hci_cmd_vs_event_length_set'
collect2.exe: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: 'D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\bin\cmake.EXE' --build 'd:\NORDIC\Projects\C50T1_RideGrid_nRF5340\build'

 *  The terminal process terminated with exit code: 1. 
 *  Terminal will be reused by tasks, press any key to close it. 

[dejans]

Hi,

Can you provide more information about your application? Is it based on any of our Bluetooth samples?

Edit:  You can look at the scanning while connecting sample. It shows how to set event_length_us parameter.

Best regards,
Dejan

[AKV]

Hi,

I have developed a custom BLE application code by using this custom_ncs_ble_service_sample tutorial. Its working fine.

We are developing a mesh network. Our requirement is the one device can connect to three other devices. Using one connection as a peripheral and up to two connections as a central for mesh connections.

We are using nRF5340 and the nRF Connect SDK Version 2.6.1.

I have attached our code in this private ticket. If needed you can refer this.  

Private ticket of other issue

[dejans]

Hi,

Thank you for additional information.

AKV said:

I have attached our code in this private ticket. If needed you can refer this.  

There are many files (including several zip files) in your previous ticket. Which file contains your code?

dejans said:

Edit:  You can look at the scanning while connecting sample. It shows how to set event_length_us parameter.

Can you look at the sample which I linked in my previous edited reply?

Best regards,
Dejan

[AKV]

Hi,

dejans said:

There are many files (including several zip files) in your previous ticket. Which file contains your code?

You can download any code, If you need latest one you download "ridegrid_06_28012025".

dejans said:

Can you look at the sample which I linked in my previous edited reply?

Yes, I have tried as given below. But the error is 

main.c:30:10: fatal error: bluetooth/hci_vs_sdc.h: No such file or directory
30 | #include <bluetooth/hci_vs_sdc.h> 

#include <bluetooth/hci_vs_sdc.h>
#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/addr.h>
#include <zephyr/bluetooth/conn.h>
#include <zephyr/bluetooth/hci.h>



sdc_hci_cmd_vs_event_length_set_t event_length_params = {
		.event_length_us = 2000,
	};

hci_vs_sdc_event_length_set(&event_length_params);

[dejans]

Hi,

I have reproduced your issue. I will look further into it. I expect to get back to you by the end of the week.

Best regards,
Dejan

[dejans]

Hi,

The issue you observed might be related to APIs inability to access controller which is on the network core.
You could try to use hci_vs_sdc which is currently recommended API for sending VS commands to the controller. This API will build and send HCI command to the controller and works even if the controller is on another CPU compared to the host/application. You can look at this commit.

Best regards,
Dejan

[AKV]

Hi,

1. I have added the hci_vs_sdc.h file to the NCS library path:

nRFConnectSDK\v2.6.1\zephyr\include\zephyr\bluetooth\hci_vs_sdc.h

2. I have added the hci_vs_sdc.c file to the NCS library path:

nRFConnectSDK\v2.6.1\zephyr\subsys\bluetooth\hci_vs_sdc.c

3. I have modified the CMakeLists.txt file in the NCS library path:

nRFConnectSDK\v2.6.1\zephyr\subsys\bluetooth\CMakeLists.txt

Added the following line:

zephyr_sources_ifdef(CONFIG_BT_LL_SOFTDEVICE hci_vs_sdc.c)

# SPDX-License-Identifier: Apache-2.0

add_library(subsys__bluetooth INTERFACE)

target_include_directories(subsys__bluetooth INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})

add_subdirectory(common)
add_subdirectory_ifdef(CONFIG_BT_HCI host)
add_subdirectory_ifdef(CONFIG_BT_SHELL shell)
add_subdirectory_ifdef(CONFIG_BT_CONN services)
add_subdirectory_ifdef(CONFIG_BT_MESH mesh)
add_subdirectory_ifdef(CONFIG_BT_AUDIO audio)
add_subdirectory_ifdef(CONFIG_BT_CRYPTO crypto)

zephyr_sources_ifdef(CONFIG_BT_LL_SOFTDEVICE hci_vs_sdc.c)

if(CONFIG_BT_CTLR AND CONFIG_BT_LL_SW_SPLIT)
  add_subdirectory(controller)
endif()

zephyr_include_directories(${ZEPHYR_BASE}/subsys/bluetooth)

add_subdirectory(lib)

4. I have enabled the CONFIG_BT_LL_SOFTDEVICE option by adding CONFIG_BT_LL_SOFTDEVICE=y in both the app core and net core config files.

But still I am getting the error 

main.c:118: undefined reference to `hci_vs_sdc_event_length_set'

Fullscreen log19032025.txt Download

 *  Executing task: nRF Connect: Build: C50T1_RideGrid_nRF5340/build (active) 

Building C50T1_RideGrid_nRF5340
C:\WINDOWS\system32\cmd.exe /d /s /c "west build --build-dir d:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build d:/NORDIC/Projects/C50T1_RideGrid_nRF5340"

[0/25] Performing build step for 'mcuboot_subimage'
ninja: no work to do.
[26/26] Linking C executable zephyr\zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:       22332 B      34176 B     65.34%
             RAM:        3456 B        64 KB      5.27%
           SRAM1:          0 GB        64 KB      0.00%
        IDT_LIST:          0 GB        32 KB      0.00%
[57/202] Building C object zephyr/CMakeFiles/zephyr.dir/subsys/bluetooth/hci_vs_sdc.c.obj
FAILED: zephyr/CMakeFiles/zephyr.dir/subsys/bluetooth/hci_vs_sdc.c.obj 
D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\zephyr-sdk\arm-zephyr-eabi\bin\arm-zephyr-eabi-gcc.exe -DEXT_API_MAGIC=0x281ee6de,0xb845acea,13570 -DFIRMWARE_INFO_MAGIC=0x281ee6de,0x8fcebb4c,13570 -DKERNEL -DNRF5340_XXAA_NETWORK -DPICOLIBC_LONG_LONG_PRINTF_SCANF -DUSE_PARTITION_MANAGER=1 -DVALIDATION_INFO_MAGIC=0x281ee6de,0x86518483,79106 -DVALIDATION_POINTER_MAGIC=0x281ee6de,0x6919b47e,79106 -D_FORTIFY_SOURCE=1 -D_POSIX_C_SOURCE=200809 -D__LINUX_ERRNO_EXTENSIONS__ -D__PROGRAM_START -D__ZEPHYR__=1 -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/kernel/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/arch/arm/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrf/drivers/mpsl/clock_control -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/include -ID:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/hci_ipc/zephyr/include/generated -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/soc/arm/nordic_nrf/nrf53 -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/soc/common/nordic_nrf/. -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/soc/arm/nordic_nrf/common/. -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/subsys/bluetooth -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/subsys/settings/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrf/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrf/lib/multithreading_lock/. -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrf/subsys/bluetooth/controller/. -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrf/tests/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/modules/hal/cmsis/CMSIS/Core/Include -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/modules/cmsis/. -ID:/NORDIC/nRFConnectSDK/v2.6.1/modules/hal/nordic/nrfx -ID:/NORDIC/nRFConnectSDK/v2.6.1/modules/hal/nordic/nrfx/drivers/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/modules/hal/nordic/nrfx/mdk -ID:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/modules/hal_nordic/nrfx/. -ID:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/hci_ipc/modules/libmetal/libmetal/lib/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/modules/lib/open-amp/open-amp/lib/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/modules/crypto/tinycrypt/lib/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/fem/common/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/fem/nrf21540_gpio/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/fem/nrf21540_gpio_spi/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/fem/simple_gpio/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/fem/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/fem/include/protocol -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/include -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/mpsl/include/protocol -ID:/NORDIC/nRFConnectSDK/v2.6.1/nrfxlib/softdevice_controller/include -isystem D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/lib/libc/common/include -fno-strict-aliasing -O2 -imacros D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/hci_ipc/zephyr/include/generated/autoconf.h -fno-printf-return-value -fno-common -g -gdwarf-4 -fdiagnostics-color=always -mcpu=cortex-m33+nodsp -mthumb -mabi=aapcs -mfp16-format=ieee -mtp=soft --sysroot=D:/NORDIC/nRFConnectSDK/toolchains/cf2149caf2/opt/zephyr-sdk/arm-zephyr-eabi/arm-zephyr-eabi -imacros D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/include/zephyr/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined -Wno-unused-but-set-variable -Werror=implicit-int -fno-pic -fno-pie -fno-asynchronous-unwind-tables -ftls-model=local-exec -fno-reorder-functions --param=min-pagesize=0 -fno-defer-pop -fmacro-prefix-map=D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/samples/bluetooth/hci_ipc=CMAKE_SOURCE_DIR -fmacro-prefix-map=D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr=ZEPHYR_BASE -fmacro-prefix-map=D:/NORDIC/nRFConnectSDK/v2.6.1=WEST_TOPDIR -ffunction-sections -fdata-sections --specs=picolibc.specs -std=c99 -MD -MT zephyr/CMakeFiles/zephyr.dir/subsys/bluetooth/hci_vs_sdc.c.obj -MF zephyr\CMakeFiles\zephyr.dir\subsys\bluetooth\hci_vs_sdc.c.obj.d -o zephyr/CMakeFiles/zephyr.dir/subsys/bluetooth/hci_vs_sdc.c.obj -c D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/subsys/bluetooth/hci_vs_sdc.c
D:/NORDIC/nRFConnectSDK/v2.6.1/zephyr/subsys/bluetooth/hci_vs_sdc.c:8:10: fatal error: bluetooth/hci_vs_sdc.h: No such file or directory
    8 | #include <bluetooth/hci_vs_sdc.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

[65/202] Building C object modules/nrf/subsys/bluetooth/controller/CMakeFiles/..__nrf__subsys__bluetooth__controller.dir/hci_driver.c.obj
ninja: build stopped: subcommand failed.
[4/25] Linking C executable zephyr\zephyr_pre0.elf
FAILED: zephyr/zephyr_pre0.elf zephyr/zephyr_pre0.map D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/zephyr/zephyr_pre0.map 
cmd.exe /C "cd . && D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\zephyr-sdk\arm-zephyr-eabi\bin\arm-zephyr-eabi-gcc.exe  -gdwarf-4 @CMakeFiles\zephyr_pre0.rsp -o zephyr\zephyr_pre0.elf  && cmd.exe /C "cd /D D:\NORDIC\Projects\C50T1_RideGrid_nRF5340\build\zephyr && D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\bin\cmake.exe -E true""
d:/nordic/nrfconnectsdk/toolchains/cf2149caf2/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: app/libapp.a(main.c.obj): in function `main':

D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/src/main.c:118: undefined reference to `hci_vs_sdc_event_length_set'

collect2.exe: error: ld returned 1 exit status
FAILED: modules/nrf/samples/hci_ipc_subimage-prefix/src/hci_ipc_subimage-stamp/hci_ipc_subimage-build hci_ipc/zephyr/zephyr.hex hci_ipc/zephyr/zephyr.elf hci_ipc/zephyr/merged_CPUNET.hex D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/modules/nrf/samples/hci_ipc_subimage-prefix/src/hci_ipc_subimage-stamp/hci_ipc_subimage-build D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/hci_ipc/zephyr/zephyr.hex D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/hci_ipc/zephyr/zephyr.elf D:/NORDIC/Projects/C50T1_RideGrid_nRF5340/build/hci_ipc/zephyr/merged_CPUNET.hex 
cmd.exe /C "cd /D D:\NORDIC\Projects\C50T1_RideGrid_nRF5340\build\hci_ipc && D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\bin\cmake.exe --build . --"
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: 'D:\NORDIC\nRFConnectSDK\toolchains\cf2149caf2\opt\bin\cmake.EXE' --build 'd:\NORDIC\Projects\C50T1_RideGrid_nRF5340\build'

 *  The terminal process terminated with exit code: 1. 
 *  Terminal will be reused by tasks, press any key to close it. 

Can you please confirm if the above steps are correct or if I am missing anything?