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

[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.