Questions related to UUID

RE: Questions related to UUID

Hung Bui — Tue, 12 May 2020 08:11:34 GMT

Hi Shinyc,

Please study the ble_app_uart_c example. You need to get to know how the example uses NUS_BASE_UUID as the base UUID and combine with BLE_UUID_NUS_SERVICE and BLE_UUID_NUS_RX_CHARACTERISTIC and BLE_UUID_NUS_TX_CHARACTERISTIC to match with the UUID that you see in nRF Connect.

Please be aware that the service and characteristic of a profile usually share the same UUID base, and only byte 13 and 14 are different. In your case you have byte 01 are different. This meant that you don't have the same UUID base and it's wrong. You should have them share the same UUID base, and only byte 13 and 14 are different for service and characteristics UUID.

RE: Questions related to UUID

shinyc — Tue, 12 May 2020 01:16:25 GMT

Hi Hung Bui,

Thank you for the reply.

You don't seem to understand my question. (Or maybe it's something I didn't understand....)

The screenshot below(nRF Connect App) and UUID is the information of the robot I want to control.

-Unknown Servie UUID : 8903136C-5F13-4548-A885-C58779136701

-Unknown Characteristic UUID : 8903136C-5F13-4548-A885-C58779136702

-Unknown Characteristic UUID : 8903136C-5F13-4548-A885-C58779136703

(As you can see, only the first BYTE value is different.)

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And when analyzed with wireshark, the following results were obtained.

1) The screenshot above is when controlling the LED of the robot.

And the following UUID is used.

-service UUID : 8903136C-5F13-4548-A885-C58779136701

-UUID : 8903136C-5F13-4548-A885-C58779136703

2) The screenshot above is when controlling the Motor of the robot.

And the following UUID is used.

-service UUID : 8903136C-5F13-4548-A885-C58779136701

-UUID : 8903136C-5F13-4548-A885-C58779136702

(If I try to control the motor and use the UUID required for LED control, I cannot control the motor.)

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I want to control this robot using a controller (Central).

However, in the ble_central (s130, ble_app_uart) example, I can't figure out what to fix.

Please tell me this part.

Thank you very much.

RE: Questions related to UUID

Hung Bui — Mon, 11 May 2020 13:49:28 GMT

Hi Shinyc,

Yes you need to either modify the NUS_BASE_UUID base and the BLE_UUID_NUS_SERVICE, BLE_UUID_NUS_RX_CHARACTERISTIC to match with your own UUID of the robot. Or declare your own base UUID and then use it in the central code.

It should be something like:

ROBOT_BASE_UUID {{0x01,0x67,0x13 .... ,0x5F, 0x00,0x00, 0x03, 0x89}}

And the Service UUID will be: 0x13bc and characteristic will be something else (in your screen shot the characteristic and the service have the same UUID which is wrong)