Size of service UUID sdk12.3 (nrf51822) softdevice130

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

akash — Mon, 20 Nov 2017 17:38:36 GMT

Not yet, it seems like some masking issue in my code itself (since the example code works fine). I actually just decided to use 0x0008 as service ID which works out just fine.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

MartinBL — Mon, 20 Nov 2017 11:20:29 GMT

Hi, Have you found a cause for this yet? Sorry for the late response. I have been out traveling the last couple of weeks.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

akash — Fri, 27 Oct 2017 17:02:18 GMT

Hi Martin,

It never disconnects or error out in either case. In the first case (when service UUID is > 4 bytes) central finds the peripheral service but never completes the device discovery but in the second example it does completes the device discovery (as you can see in the log). The system still stays healthy and functioning in both cases. No error. Somehow its not liking me setting UUID > 4 bytes.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

MartinBL — Fri, 27 Oct 2017 08:40:21 GMT

The first log says it is connected. It even finds your UUID. Do you mean that it connects and then disconnects without warning? Have you debugged your code and looked for errors and asserts like this? It wouldn't surprise me if the central examples somewhere doesn't like your new UUID and produces an error and send your application into an error handler function, effectively breaking your BLE connection.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

akash — Thu, 26 Oct 2017 22:55:04 GMT

thanks! I will try to get the sniffer logs.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

endnode — Thu, 26 Oct 2017 22:49:53 GMT

Here is link to Nordic cheap sniffing solution (special FW for nRF51 DK or Dongle, unofficial FW for nRF52 Dk can be found on this forum as well). But indeed there are many other tools and variants, from few USD up to dozens of thousands. I would bet that if you go back to stock SDK examples of NUS Central and Peripheral, change just 16bit UUID of the service it will work. Kind of indication where is the problem... but maybe there is some wrong cast or whatever which will be already in the example. In every case there is nothing like "length" of UUID, zeros count indeed, that number is in the end used as 16-bit part of entire 128-bit UUID, trust me;)

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

akash — Thu, 26 Oct 2017 22:25:15 GMT

Yes, I am just changing the constant on both sides. Its not about the 0s but the bit size of the UUID value itself. I haven't change the device discovery part much. Biggest change in my code is, my device has both central and peripheral role at same time (not sure if the problem is related to that though).

Can you please point me to some tutorial how to get sniffer/analyzer logs? I am pretty new to BLE programming.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

endnode — Thu, 26 Oct 2017 22:18:13 GMT

You mean that you are changing the constant on both sides and is stops working depending on how many non-zero bits UUID has? That sounds really strange. Btw. the UUID you talk about has always 16-bits, the fact that some are zeros doesn't make it shorter. Are you sure there isn't some nasty conversion done on top o that constant before you use it as 16-bit unsigned integer in UUID structure? If you are sure that all is correct could you show us radio log from some sniffer/analyzer to see what exactly happens on GATT layer and what is source of the error?

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

akash — Thu, 26 Oct 2017 21:54:18 GMT

I am using softdevice s130v2. I am using the ble_central\ble_app_uart_c and ble_peripheral\ble_app_uart_c example code from sdk12.3.

I am talking about size of service UUID (BLE_UUID_NUS_SERVICE) which is 0x0001 in the code and not the base UUID (NUS_BASE_UUID) which is 128 bit. Everything works fine in the example code and also in my code if I keep the service UUID < 4 bit. If I change the service UUID to say 0x0022 it won't work.

RE: Size of service UUID sdk12.3 (nrf51822) softdevice130

endnode — Thu, 26 Oct 2017 21:06:14 GMT

Sorry but this doesn't make any sense. Firstly GATT UUID is matter of stack so you should refer SoftDevice version (if you use Nordic Soft Device) and not SDK. Second all Nordic SD API work with 128-bit(16-byte) base (in the form of reference to table provisioned through Soft Device API earlier) and 16-bit (2-byte) "short" UUID. Could you be more precise what SDK example you use and what changes you made to the code? COuld you go back to generic example and verify that (indeed) all works fine?