I want to advertise 2 custom UUID in the Gap advertising

RE: I want to advertise 2 custom UUID in the Gap advertising

Jean-marie — Thu, 28 Nov 2019 10:36:30 GMT

Hi Hung, Thanks for your reply, but my problem is to make the 128BIT SERVICE DATA, the first one the Battery Level is OK.

The picture I've send to you is made with Zerynth ide in Python !

I must do the same with Segger Embedded Studio, but I am very new in C langage and I need to be helped with information or in a better way with an working example.

Can you help me ?

Best regards

Jiemde

RE: I want to advertise 2 custom UUID in the Gap advertising

Hung Bui — Thu, 28 Nov 2019 10:13:40 GMT

Well, a picture is worth a thousand words, but a picture with good explanation is even better.

The battery service UUID is 0x180F. It's a 16 bit UUID because it's a Bluetooth SIG service, and it can be used with short UUID (16bit) this is the short form of a 128bit UUID with the Bluetooth SIG base UUID. See here: https://www.bluetooth.com/specifications/assigned-numbers/service-discovery/

The custom service, has the type 0x21 SERVICE_DATA_128BIT and the full UUID is as in the picture started with 0000 and ends with 4c45. It's 128bit. The data of the service is 12 34 56 78.

So what you are doing is correct. You can see that the nRFConnect can parse the advertising package with no problem. Keep in mind that this is possible because the battery service has short UUID, it's not "custom UUID" .

If you are doing 2 128bit UUID then it won't fit in one package.
I got an old blog here, could be useful: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/bluetooth-smart-and-the-nordics-softdevices-part-1

RE: I want to advertise 2 custom UUID in the Gap advertising

Jean-marie — Wed, 27 Nov 2019 15:03:15 GMT

Think that pictures explain more than one million words.

So you can see that there is an SERVICE_DATA " 0x16 " for the Battery Level and a SERVICE_DATA_128BIT " 0x21 " for the display of 4 bytes of Data " 12 34 56 78 "

Thanks for your helping

Jiemde

RE: I want to advertise 2 custom UUID in the Gap advertising

Hung Bui — Wed, 27 Nov 2019 14:00:33 GMT

Hi Jean,

Could you clarify what your custom UUID are ? It should be 128 bit long, not 8 bit as you described.

You can't have both 128 bit UUID in a single advertising packet. But it should be possible using 2 packets (scan response packet)