Is it required to program STM32L1 for using BlueNRG-1/2 in network coprocessor mode ?

[MH1]

Hello,

I would like to design my own PCB for a Bluetooth Mesh project. Currently I am using STEVAL-IDB007V1 and STEVAL-IDB008V2 boards by configuring and provisioning them as mesh nodes through smartphone. I want to know whether it is required to program the STM32L151CBU6 microcontroller in order to use BlueNRG-1/2 in network coprocessor mode ?

In the documentation, it is mentioned that "In order to configure the BlueNRG-2 device as a network coprocessor, the device must be programmed with a specific application, named DTM (direct test mode). " Moreover , it is also mentioned that

"The STM32L microcontroller on the board is not intended to be programmed by users. ST provides a preprogrammed firmware image for the sole purpose of interfacing BlueNRG-1, BlueNRG-2 to a USB host device (e.g., a PC)."

So, I want to ask if I want to design my own PCB for BlueNRG-1/2, then is it required to program firstly the STM32L microcontroller with the DTM source code provided in SDK ? Kindly let me know the necessary steps.

[MH1]

@alok​ @STM Community​  ...Could you please help ?

[alok]

Hi MH,

The BlueNRG-1, -2 can be used in 2 modes: Network coprocessor mode or Application processor

The comments you have mentioned are for Network co-processor mode. Because in this case the external controller (STM32) is needed.

For the Mesh firmware example you are using in STSW_BNRG-Mesh solution, the BlueNRG-1, 2 are used in Application mode. The device can work independently without a need of STM32

Hope it is clear

In addition, the STM32 available on the STEVAL-IDB007V1 and STEVAL-IDB008V2 boards is to provide the USB-UART bridge. Also, it provides functionality to drag-drop the binary file to program the BlueNRG-1, -2.

So, you can design your own hardware without any STM32L1

[MH1]

Hi Alok,

Thank you for reply. If I use only BlueNRG-1,2 without STM32L1, how can I program the output or binary files to BlueNRG-1,2 on my own hardware board ? What changes do I need to make to connections of BlueNRG-1,2 in schematic of STEVALIDB007V1 board ?

[alok]

Hi MH,

You need the SWD connections. Refer to schematics for example for this design which is based on BlueNRG-2: STEVAL-BCN002V1B  

Schematics are inside the Databrief:

https://www.st.com/resource/en/data_brief/steval-bcn002v1b.pdf

You will surely need a programming tool like ST-LINK/V2

[MH1]

Hi @alok​ ,

I tested the SWD connection to program BlueNRG-1,2 using ST Link/v2 and it worked. I want to further confirm that for programming mesh firmware on BlueNRG-1,2, there is no need of sheet 2 in this schematic and can I implement mesh firmware by using only sheet 1 and 3 of this schematic ?

https://www.st.com/content/ccc/resource/technical/layouts_and_diagrams/schematic_pack/group0/7c/37/69/17/1f/c8/42/e8/STEVAL-IDB007V2_schematics/files/STEVAL_IDB007V2_schematic.pdf/jcr:content/translations/en.STEVAL_IDB007V2_schematic.pdf

[MH1]

Hi @alok​ ,

Can you also tell me the value of inductor "L5" used for both STEVAL-IDB007V2 and STEVAL-IDB008v2 ?

Its value is not mentioned either in schematic or BOM.

[alok]

Hi MH,

In my opinion, L5 will depend on the recommendation of the XTAL used. You can leave the footprint for the bead

[MH1]

Hi ,

Can you let me know the values for both cases i.e. for 32MHz crystal (used in STEVAL-IDB008V2) and 16 MHz crystal (used in STEVAL-IDB007V2) ?

[MH1]

Hi @alok​ ,

Could you please reply to this question as well ?