Service discovery, attribute not found 0x0001

[laran]

Dear all,

I am having issues with service discovery of two primary services ( Battery and one propriotary based on NUS) I am currently using SDK 14.2 on NRF52832 chip running as central device application trying to discover these services on off-the shelf peripheral devices (thermal printers to be more specific).

I have tried with different devices (different brands with same UUID) and with some of them the service discovery works and I am able to send data to the printer. It also works when I connect using nRF Connect on my Android device.

I have logged the communication with Wireshark however don't understand why I get the "Attribute Not Found, Handle: 0x0001 (Unknown)

Sorry for being somewhat brief in my description. The thing is that I am not sure I am actually looking at this problem from the right angle. I am not certain the service discovery is wrong. It may be that I missed something in the configuration. If so, how do I find out what?

Thanks for any help getting on track with this.

[Bjørn Kvaale]

If you take a look at Chapter 3.4.1.1 Error Response in the Bluetooth Core Specification , you can see that the error code 0x0A  refers to: "No attribute found within the given attribute handle range". According to this case, this error code is sent for characteristics that do not have a value. Which example from SDK 14.2 are you basing your code off of? Could you upload the whole wireshark log for me to take a look at please? Also, which version of wireshark & nrf sniffer are you currently using?

[laran]

My project is based on the ble_app_uart_c example with the battery service added to it. I am running Wireshark 2.4.6 using the nrf-sniffer-2.

I have uploaded the Wireshark logg. Go to message 520 for a start.

POS-5802.pcapng

[Bjørn Kvaale]

What kind of Bluetooth chip do the thermal printers use? If service discovery works using nrf connect, it seems you have done this part correctly. If the thermal printers do not use a Nordic Bluetooth chip, it could be that there is some kind of service discovery error occurring on the server side in the thermal printers.

[laran]

I am sorry, I was unclear. nrf Connect is able to do the service discovery on all the printers. My implementation on the nrf52 chip works on some of them. I still expect something is wrong with my code.

When looking at package 520 one can see the the 128 bit service is broadcasted by the printer. Then in package #526 the primary service declaration request is hapening, asking for the same 128 bit value, right? then in #527 the "not found" response happen. Starting at package 35052 one can see how the connection and service discovery between the printer and nrf connect my android device.  I interpret it as the printer uses a CSR chip.

I attach a Wireshark log with a device that work. the service discovery starts at package #224

PTP-II.pcapng

[Bjørn Kvaale]

Sorry for the delayed response. I have taken a closer look at the uart central example & I believe this example only searches for the uart service. I think it would be better if you tested with the multilink central example, as that example does not limit itself to the uart service.

[laran]

Just for a quick test I used the  multilink central example you suggested. Since it already has the battery service it was perfect for testing this. However, it does not connect here either. I'll uplode a Wireshark log later today.

[Bjørn Kvaale]

That's weird. Do you also have any logging information from the multilink example that you could upload? Might be helpful in debugging this further.

[SRA]

Just a heads up that I have a similar issue in another post. Also getting Attribute Not Found for three of my characteristics on discovery. So I'm interested in the response here.

[laran]

I have had major issues with Wireshark. I can't get it to capture anything else then advertisement packages. Occasionally I get a scan request from some Apple device in the area. therefore my logs are useless at the moment. I have tried to recreate the loggs I made earlier without luck.

The best I can do for now is the debug output from the debug output.

<debug> nrf_sdh: State request: 0x00000000
<debug> nrf_sdh: Notify observer 0x00027D78 => ready
<debug> nrf_sdh: State change: 0x00000000
<debug> nrf_sdh: State change: 0x00000001
<debug> nrf_sdh_ble: RAM starts at 0x20004190
<info> app: Multilink example started.
<info> app: Start scanning for device 46 2C 90 17 02 0F
<debug> nrf_sdh_ble: BLE event: 0x1D.
<debug> app: Adv report.
<info> app: Connecting to target 62 CE BB 51 F9 F4
<debug> nrf_sdh_ble: BLE event: 0x1D.
<debug> app: Adv report.
<info> app: Connecting to target 90 63 86 95 13 15
<debug> nrf_sdh_ble: BLE event: 0x1D.
<debug> app: Adv report.
<info> app: Connecting to target 46 2C 90 17 02 0F
<debug> nrf_sdh_ble: BLE event: 0x10.
<info> app: Connection 0x0 established, starting DB discovery.
<debug> ble_db_disc: Starting discovery of service with UUID 0x180F on connection handle 0x0.
<debug> nrf_sdh_ble: BLE event: 0x30.
<debug> ble_db_disc: Service UUID 0x180F not found.
<debug> app: call to ble_lbs_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_bas_c: Battery Service discovery failure at peer.  
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> ble_db_disc: Service UUID 0x0 not found.
<debug> nrf_sdh_ble: BLE event: 0x11.
<info> app: LBS central link 0x0 disconnected (reason: 0x8)
<info> app: Start scanning for device 46 2C 90 17 02 0F
<debug> nrf_sdh_ble: BLE event: 0x1D.
<debug> app: Adv report.
<info> app: Connecting to target 59 E1 D5 4E 74 C0
<debug> nrf_sdh_ble: BLE event: 0x1D.
<debug> app: Adv report.
<info> app: Connecting to target 46 2C 90 17 02 0F
<debug> nrf_sdh_ble: BLE event: 0x10.
<info> app: Connection 0x0 established, starting DB discovery.
<debug> ble_db_disc: Starting discovery of service with UUID 0x180F on connection handle 0x0.
<debug> nrf_sdh_ble: BLE event: 0x30.
<debug> ble_db_disc: Service UUID 0x180F not found.
<debug> app: call to ble_lbs_on_db_disc_evt for instance 0 and link 0x0!
<debug> ble_bas_c: Battery Service discovery failure at peer.  

[Bjørn Kvaale]

It seems the on_primary_srv_discovery_rsp() function is printing out the "Service UUID 0x0 not found" to the log. The reason for this is that the line "p_ble_gattc_evt->gatt_status" inside the if block of the on_primary_srv_discovery_rsp() function inside ble_db_discovery.c of the multilink example does not return BLE_GATT_STATUS_SUCCESS. Could you set a breakpoint here or print out what the GATT status code is? If you are still using SDK v 14.2 with Softdevice v5.0.0, you can find the different GATT status codes here.

[laran]

Yes, I am still using SDK 14.2 with SD s132 (v5.0.0)

This is what I get when printing out the GATT status:
<debug> ble_db_disc: Service UUID 0x180F not found (GATT Status = 0x010A).