CC2564B: Generic Attribute Service has no "Service Changed" Characteristic

Have you tried using the GATT_Service_Changed_Indication()?

The stack is supposed to handle the "Service Changed" characteristic internally.

Hello Kobi, 

GATT_Service_Changed_Indication() would be the second step.

First of all the "Service Changed" characteristic should be offered internally, so it could be subscribed by a bondend device. 

Issue -> "Service Changed" characteristic is not offered internally / Generic Attribute Service stays empty 

I'll need to check this. I will respond here when i have more details.

This subscription for the "service changed" should  be automatic for the bonded device.

GATT_Service_Changed_Indication() should just work (send the indication).

What is the exact issue that you are facing?

Hello Kobi,

What do you mean by "This subscription for the "service changed" should  be automatic for the bonded device."

My usecase:
One peripheral device (Smartphone Android/iOS or Ble Dongle) is connected and bonded to the central device (CC2564). 

The peripheral device makes a service discovery and will find the Generic Attribute Service, but the Generic Attribute Service has no characteristics (No Service Changed characteristic is found). If the characteristic is not available how should the peripheral subscribe to the Service Changed characteristic?
All other custom defined services/characteristics are found and handled correctly.

Is there any builtin option for CC2564 to enable the service changed feature or characteristic?
Do I miss something in gatt initialize?
Are any additional steps/function calls required to activate the feature or characteristic?
Ist there any working example?

why do you need to subscribe to the "service changed" characteristic?

you should get the indication regardless when GATT_Service_Changed_Indication is triggered.

My thought:
If you want to received notifications or indications of a specific characteristic you have to subscribed the CCCD before. Or do i miss something?

Looking at the SSPLE demo in our SDK, we can see that the "Service Changed" characteristic is available.

What is the code that you are based on?

Base Project was SPPLE Demo. 

and you don't see the "Service Changed" characteristic in the original sample app?

Custom Hardware TM4C 129 and CC2564B with our own Applilation based on SPPLE Demo.


Calling GATT_Service_Changed_Indication(unsigned int BluetoothStackID, unsigned int ConnectionID, GATT_Service_Changed_Data_t *Service_Changed_Data) returns 0 but nothing happens.

Generic Attribute Service stays empty. Everything als is working fine (Generic Access, TI OAD and all other custom Gatt Services)

(Original Sample Demo will not work directly on Hardware)

what exactly have you changed (comparing to the original code)?

Do you have any reference platform to run the original code? The BLE services should not be impacted by the platform. 

Hello Kobi,
the orginal SPPLEDemo with TI Development Board (DK-TM4C-123G) do also have the same Issue.
Generic Attribute Service doesn't have the "service changed" characteristic.

This is what I just got on an Android phone (using the "BLE Scanner" app).

On iPhone it seems that not everything is available for the user.

Hi Kobi, 
thanks you for your response.
I tried it on different Plattform Android, iOS, PC (WIndows) and also analysed it with the ellisys bluetooth analyzer, all had the same result -> no "Service Change" characteristic. Do you use a specific Service Pack? Or what could be missing?  

Best regards, 

Ben

Are you also using the CC2564B?

Hi Kobi,
can you confirm you use also the library sources from CC256XM4BTBLESW-v1.2-R2 packages?
Downloaded from https://www.ti.com/tool/TIBLUETOOTHSTACK-SDK for TM4C platforms.

Is it possible to provide us with your sorces?

Best regards,
Tobias

i’m using the MSP432 port but the issue we are discussing here is a core functionality which is common to all host platforms.

due to legal aspects we can’t provide the sources to the stack.

OK, but I guess that's why you get a different result.
It is a core functionality, but it has to be enabled building the stack library!

So it seems the library you use has been built with different options.

Is the library coming with MSP432 port compatible to run on a TM4C controller?

Are you using iOS or Android? I'm quite sure this is the source of the difference. I see the same results as you using the BLE Scanner on iPhone.

There is no platform specific configuration that will impact this. 

Hi Kobi,

We tried it with iOS, Android, Ellisys BT Tracker, nRF Connect Stick without success.
Refering to original thread the feature is enabled by a stack build option:

Is it possible to provide us with a stack with this option enabled?

Very strange - this should be enabled for all platforms.

I will need to check this.

Hi Kobi, 

do you have any udpates?

not yet. I'll try to check this by the end of the week.

BTW. the fix was for BluetopiaPM - you are using the Bluetopia port for TM4C (not BluetopiaPM), right?

Right, we are uing the Bluetopia port for TM4C.

The fix was made for BluetopiaPM according to the original thread.

We are still trying to find the details of the fix.

If it was done on the PM side - it won't be relevant here.