[nRF53] Generic UUID

[Rantanplan]

Hello,

I tried to change the defined UUIDs for the BLE service and characteristics in the LED Button Service example (lbs.h).

E.g.

/** @brief LBS Service UUID. */
#define BT_UUID_LBS_VAL \
BT_UUID_128_ENCODE(0x6e65df85, 0x2e4f, 0x4d72, 0xadf5, 0xd41d46eedf88)

But the result is somehow random. Most of the time, the original value for this service is found by the BLE scanner App.

I'm also wondering how to define the services Generic Access and Generic Attribute? Interestingly the nRF Connect App is able to show them, but other Apps like LightBlue aren't.

The environment I'm using is a nRF5340 DK, nRF Connect 2.1.0, with the configuration nrf5340dk_nrf530_cpuapp.

Many help in adding additional BLE services and characteristics would be highly appreciated.

Many thanks in advance.

[Simon]

Hello,

I'll look into this today/tomorrow

Best regards,

Simon

[Rantanplan]

Hello, 

I got a step further and realized that changes in /ncs/v2.1.0/nrf/include/bluetooth/services/lbs.h are working. But if I try to define a custom service in my local work directory, definint new UUIDs there has no effect because CONFIG_BT_LBS=y is required and loads the defaults from /ncs/v2.1.0/nrf/include/bluetooth/services/lbs.h. Without CONFIG_BT_LBS=y, the definition of GATT characteristics does not work.

So I followed the description in 

 nRF Connect SDK Bluetooth Low Energy tutorial part 1: Custom Service in Peripheral role 

which seems to work. 

Anyway, I'm still wondering why attributes like Generic Access and Generic Attributes are not shown in Apps other than nRF Connect.

[Simon]

Rantanplan said:

Anyway, I'm still wondering why attributes like Generic Access and Generic Attributes are not shown in Apps other than nRF Connect.

I would think the reason that these services are not present in any other apps, are because they are not very useful for users. These are added by the stack and can not be modified in any way. See

 Custom GAP Service with User Descriptions (UUID 0x2901) 

 How to remove generic access and generic attribute profiles 

Best regards,

Simon

[Rantanplan]

Hi Simon,

as far as I understand the Bluetooth standard, those characteristics are mandatory and should be readable without any burden.

Therefore I'd like to understand how they are hidden.

And one additional question:

How to set the characteristic "Manufacturer Name" (0x2a29) and "Model Number" (0x2A24) inside the service "Device Information" (180A) or the "Device Name" (0x2a00) in "Generic Access" (0x1800)? 

Many thanks in advance.

Kind regards,

Christian

[Simon]

Rantanplan said:

Therefore I'd like to understand how they are hidden.

Rantanplan said:

Anyway, I'm still wondering why attributes like Generic Access and Generic Attributes are not shown in Apps other than nRF Connect.

I'm not sure about this. I can look into it and get back to you if you would like. Would you be able to ask the companies/peoples of these apps, why they hide these services?

Rantanplan said:

How to set the characteristic "Manufacturer Name" (0x2a29) and "Model Number" (0x2A24) inside the service "Device Information" (180A)

Check out the sample zephyr/samples/bluetooth/peripheral_dis, it sets Manufacturer name to "Zephyr Manufacturer", Model Number to "Zephyr Model" and some of the characteristics are set through Kconfigs

https://github.com/nrfconnect/sdk-zephyr/blob/v3.1.99-ncs1/samples/bluetooth/peripheral_dis/prj.conf#L13-L15

https://github.com/nrfconnect/sdk-zephyr/blob/v3.1.99-ncs1/samples/bluetooth/peripheral_dis/src/main.c#L61-L77

Rantanplan said:

or the "Device Name" (0x2a00) in "Generic Access" (0x1800)? 

Try setting CONFIG_BT_DEVICE_NAME="my name" in prj.conf, like done in the Bluetooth Peripheral UART sample: https://github.com/nrfconnect/sdk-nrf/blob/v2.1.0/samples/bluetooth/peripheral_uart/prj.conf. You can also set it in runtime if you enable CONFIG_BT_DEVICE_NAME_DYNAMIC.

Best regards,

Simon

[Rantanplan]

Hello Simon,

many thanks for the advice, this seems to work.

Interestingly, after enabling the Device Information Service (CONFIG_BT_DIS), the characteristics "Manufacturer Name" and "Model Number" are also found by other Bluetooth Apps, not only by the nRF Connect App.

Thanks again and kind regards,

Christian