Custom BLE service can't read all characteristics

[MicSch]

Hello guys,

I'm currently trying to get notifications from a custom ble service. I can connect to the service, but I only see 6 out of 9 characteristics.
The first pic shows the ble communication between my central and the peripheral device. The second picture shows the communication between the nrf connect ble app and the peripheral.

It seems like the service is devided into two section. Do you have any suggestion how I can discover the last 3 characteristics?

[Hung Bui]

Hi MicSch, 

Could you give more information about your central ? Did you use our service discovery library to do the task ? 

Please attach the sniffer trace file so we can have a look. 

My understanding is that after receiving ATT_READ_BY_TYPE_RSP and the result was not "Attribute Not Found " you would need to continue sending ATT_READ_BY_TYPE_REQ again with the start handled updated until you receive "Attribute not found" Please see Section 4.6.1 Vol 3 Part G in Bluetooth Spec. 

[MicSch]

Hello Hung Bui,

I'm using the ble_db_discovery lib. I changed a client example to be able to discover the custom service. It's running on a nrf52832 chip. In the meantime I will try to find the query for the ATT_READ_BY_TYPE_RSP response.

Here are the two traces.

snifferTraceCentral.pcapngsnifferTraceBleApp.pcapng

[Hung Bui]

Hi MicSch, 

I found this declaration BLE_DB_DISCOVERY_MAX_SRV  set to 6 in the ble_db_discovery.h . It matched with what you observed.

Could you try to increase it  ? 
I'm not sure if all of your characteristic is under the same service or not, but if they are, then you need to increase BLE_GATT_DB_MAX_CHARS as well. 

[MicSch]

They are indeed under the same service. I increased both, but it didn't work. BLE_GATT_DB_MAX_CHARS wasn't declared in the library or the sdk_confiq file, but it doesnt matter where I declare it?
I will try do search for the query of the ATT_READ_BY_TYPE_RSP response tomorrow, maybe this will fix the issue.

[Hung Bui]

Hi MicSch, 

Have you modified BLE_DB_DISCOVERY_MAX_SRV  inside ble_db_discovery.h ? 

[MicSch]

Yes I modified the BLE_DB_DISCOVERY_MAX_SRV in ble_db_discovery.h