How can I make peripheral device name configurable?

[PingISTL]

Dear all

I am developing a BLE product, and would like to have a different device name for each unit like Product1, Product2 etc. when advertising, so user can identify each of them.

I noticed Device name in Generic Access service is read only, is there a way I can configure it differently?

Regards!

Ping

[Hieu]

Hi, one solution you can try is to concatenate the device name with information from in the Factory Information Configuration Registers (FICR). It's best to use the read-only, factory written Device ID.

You can explore more here:

nRF5 SDK: https://infocenter.nordicsemi.com/topic/drivers_nrfx_v2.7.0/group__nrf__ficr__hal.html

nRF Connect SDK: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfx/drivers/ficr/hal.html?highlight=ficr

Best regards,
Hieu

[PingISTL]

Hello, Hieu

Thanks for reply!

I use nrf Connect v1.9.1 and VS Code. Not sure above API is valid with this version?

The BLE is hosted by another MCU, and the unique ID is better from my host MCU, my question is - is it possible to make it configurable after it is programmed with an initial default factory device name.

Regards!

Ping 

[Hieu]

Hi,

The API is actually valid in NCS v1.9.1 too: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/nrfx/drivers/ficr/hal.html.

I'm afraid I don't fully understand your setup. Are you saying you need the unique ID to be provided to the nRF52 chip from a different MCU?

In any case, there are a number of ways to influence the device's "appearance" to a scanner.

First solution: Advertise with Local Name data, and update that data. This can be done even during advertising.

The caveat is that the Local Name has to be the same or a shortened version of the Device Name itself.
See the section about Local Name in Bluetooth Core Specification Supplement for more details.

But anyway, the actual caveat is, if you want to add some dynamic run-time determined element to the Local Name, you are required by Bluetooth Spec to update the device name itself. Which brings us to:

Second solution: Advertise with Device Name data. If name has to be changed, stop advertising, set new name, and start advertising again.

There might be more ways. But now I can only think of those two.

[PingISTL]

Thank you for your contribution, Hieu

My application requires a name change after it starts up, to attach a bit more id related information in the name. 

It is a good idea that it starts with local device name - shorted version of like Product , and then attach a ID. so, it becomes ProductID later. In my application the ID is from host MCU via serial interface.

I don't mind stop advertising and restart again later, my question is - do I define two set of ad data like below?  I might need to make the complete device name as a variable, I suppose? Do I advertise with both local name and complete device name? any examples please?

#define DEVICE_NAME             CONFIG_BT_DEVICE_NAME
#define DEVICE_NAME_LEN         (sizeof(DEVICE_NAME) - 1)

static const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
};

 

Regards!

Ping

[Hieu]

Hi Ping,

Yes, what you are doing is one correct way of doing it. Just want to point out a few things to be careful about it:

1. If you are not using the full name of your device in the advertisement, you should use the ad data flag BT_DATA_NAME_SHORTENED instead of BT_DATA_NAME_COMPLETE. Apparently it will still work, but it is improper.
   
   
2. If you are already providing a Local Name data in your bt_data_ad array, don't set the bt_le_adv_param.option BT_LE_ADV_OPT_USE_NAME when creating advertisement set or starting advertisement.
   I did some quick experiments and both bt_le_ext_adv_set_data() and bt_le_adv_start() don't like it and will fail.
   
   (And as you might have guessed, one different way is the opposite BT_DATA_NAME_COMPLETE and just use the advertising option BT_LE_ADV_OPT_USE_NAME.)
   
   
3. Remember to set the Kconfig CONFIG_BT_DEVICE_NAME_DYNAMIC appropriately

If you want to discover different solutions, you can also try looking into Manufacturer Data and a custom app parsing data from it as well. Depends on your product design, it might be more suitable.

Best regarsd,
Hieu

[PingISTL]

Thank you, it works now, just don't think the last option(CONFIG_BT_DEVICE_NAME_DYNAMIC ) is necessary as I stop adv first and restart again after I got a full name with ID.

One more question, I need to save the full device name with ID once it is received, so it stays over power cycles, how can I do that please?

Regards!

Ping

[Hieu]

Hi Ping,

Good to know that things are working. Also interesting to know that CONFIG_BT_DEVICE_NAME_DYNAMIC doesn't matter.
Its name is very clear and it has always been on for me so I didn't check what happened if it is turned off. Interesting, I wonder what it is for then.

Regarding saving over power cycles, you could refer to this recent Q&A:  RE: Recommended solution for persistent data storage in NCS . The question looks different at first but they are discussing exactly what you need over there.

Best regards,
Hieu