Creating a custom UART connection over BLE

[tolab]

I would like to use the ble_app_uart_c example, found here, to connect to a custom peripheral. What values should I change in the central device code in order to connect to a device, service, and characteristic of my choice?

I am guessing I need to change the UUID of the service I am searching for. Also, I assume should be able to change the UUID's for the RX and TX characteristics of the service I want to read from and write to.

Do I need to change how the handles for these characteristics are retrieved? Are there any another changes I need to make in order to get the nRF52 to establish a serial connection with my device?

I am using IAR, and the nRF52832 with softdevice 132 loaded onto it.

[endnode]

If you change all UUID values correctly then GATT service discovery in ble_db_discovery module should make the job for you.

[tolab]

The original RX and TX characteristics are 16-bit UUIDs. The UUID for my custom device is 128 bits long. How do I adjust for this?

Thanks for the response!

[endnode]

Not really. In Nordic BLE stack all UUIDs are 128-bit (that's actually true in BT SIG Core as well;). They just come in pair of values: 16-bit UUID + 128-bit UUID base. Now the only standard 128-base which is in SoftDevice pre-configured is the one defined for 16-bit BT SIG UUIDs (logical;). What Nordic BLE UART examples are doing is that they provision second (custom) 128-bit UUID to Soft Device during init and then they use it as base for all custom 16-bit UUIDs. This is the same on GATT Server as well as GATT Client side. SO the answer is: provision correctly your specific 128-bit UUID base and use it for provisioning all Service/Characteristic UUIDs together with 16-bit values (but I'm pretty sure this is already happening in Nordic SDK examples).

[tolab]

Sorry I am very new to this so I have many questions. What does it mean to provision a UUID?

Does this mean, if I change the given 128 bit UUID in the example to resemble the UUID of the characteristic I'm trying to read, it won't affect any of the other UUID's my board needs to read (i.e. the UUID for another service)? I am confused because they do not all have the same 128 bit form.

[endnode]

Cool, then spend some time by reading all the tutorials and then we can answer rest of your questions;) devzone.nordicsemi.com/.../ devzone.nordicsemi.com/.../ devzone.nordicsemi.com/.../