Custom Service Setup in Central in nRF Connect SDK

RE: Custom Service Setup in Central in nRF Connect SDK

Simonr — Tue, 06 Dec 2022 14:05:51 GMT

This project doesn't seem to have anything to do with Bluetooth LE and services, so I'm not sure I understand how this is related to your ticket, but we do have multiple USB sample projects available in the Zephyr branch here. The USB CDC ACM sample application is likely the easiest to get into.

Best regards,

Simon

RE: Custom Service Setup in Central in nRF Connect SDK

Dr. Jumba Jookiba — Tue, 06 Dec 2022 09:17:44 GMT

github.com/.../usb_cdc.c

i want to implement similar to this in nRF COnnect SDK, Do we have any similar example?

RE: Custom Service Setup in Central in nRF Connect SDK

Simonr — Mon, 05 Dec 2022 09:06:20 GMT

I would recommend using logging to try and debug this to see where exactly it would fail. As I can't think of what exactly the issue would be from these error messages. Are you able to see where the device fails exactly when this error occurs? Try setting CONFIG_LOG=y in your project config file, and add some printk() lines to make sure that steps are completed successfully. You can also use the Debug extension in VS Code, we have a tutorial video available here.

Best regards,

Simon

RE: Custom Service Setup in Central in nRF Connect SDK

Dr. Jumba Jookiba — Fri, 02 Dec 2022 12:36:15 GMT

Thank you Simonr , i have completed that part but stuck after discovering the service.
The discovery get completed and then while processing the following line

bt_gatt_dm_data_print(dm);

bt_nus_handles_assign(dm, nus);
bt_nus_subscribe_receive(nus);

bt_gatt_dm_data_release(dm);
k_sleep(K_SECONDS(10));
//bt_gatt_dm_continue(dm,context);

I get the following errors and then device reset,

[00:00:31.800,567] <err> os: ***** MPU FAULT *****
[00:00:31.800,598] <err> os: Data Access Violation
[00:00:31.800,598] <err> os: MMFAR Address: 0x4
[00:00:31.800,628] <err> os: r0/a1: 0x0000001a r1/a2: 0x00000000 r2/a3: 0x0001537b
[00:00:31.800,628] <err> os: r3/a4: 0x00015379 r12/ip: 0x000000d7 r14/lr: 0x00010d9b
[00:00:31.800,659] <err> os: xpsr: 0x01000000
[00:00:31.800,659] <err> os: Faulting instruction address (r15/pc): 0x00010da8
[00:00:31.800,689] <err> os: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
[00:00:31.800,720] <err> os: Current thread: 0x20001d98 (BT RX)

RE: Custom Service Setup in Central in nRF Connect SDK

Simonr — Fri, 02 Dec 2022 08:03:51 GMT

I'm sorry, that wasn't the best explanation. Since the nus_client.c file does not have a gatt_discover() function in the driver file you need to edit this in your main.c file instead to use the custom UUID. The central_uart samples main.c file has a gatt_discover() function that is looking for the NUS service specifically, so you need to either replace this with or add your custom service UUID here.

Unfortunately we do not have a specific walkthrough for the central side, as it is conceptually similar to how it's done on the peripheral side.

Best regards,

Simon

RE: Custom Service Setup in Central in nRF Connect SDK

Dr. Jumba Jookiba — Thu, 01 Dec 2022 09:00:32 GMT

Thank you Simonr
i have modified that file with my custom uuids.

I think i am miising this part,Also, since NUS_CLIENT does not have the discovery added, you need to change the gatt_discover() function to use the custom UUID as well.

Can you please point me to any example in which it is done.

Would really like to see a walkthrough for the central side and if possible the combination of the central and peripheral for a device.

RE: Custom Service Setup in Central in nRF Connect SDK

Simonr — Thu, 01 Dec 2022 08:35:25 GMT

You need to modify this file to recognize your custom UUID, as the nus_client.c by default is only designed to work with the NUS base UUID. Also, since NUS_CLIENT does not have the discovery added, you need to change the gatt_discover() function to use the custom UUID as well.

What exactly "isn't working" in your case?

Best regards,

Simon

RE: Custom Service Setup in Central in nRF Connect SDK

Dr. Jumba Jookiba — Wed, 30 Nov 2022 12:24:31 GMT

Thank you for quick response,
have gone through this, this example represent peripheral side of creating custom service and all.

i am working on central where i have to read the custom service after connecting to the peripheral, i have modified nus_client.c and header file to read my custom services.

But that isn't working.

RE: Custom Service Setup in Central in nRF Connect SDK

Simonr — Wed, 30 Nov 2022 12:12:02 GMT

One of my colleagues has made a Custom BLE service sample project for the nRF Connect SDK here that is made for BLE courses.

Best regards,

Simon