Understanding Nordic UART Service and RX 6 tx cHARACTERISTICS

[SpaceToon]

Hello,

I have an Adafruit Feather M0 Bluefruit LE with an nRF51822 chipset from Nordic and I am currently dealing with Bluetooth Low Energy, especially with profiles, services and characteristics. I have read that there are predefined profiles (SIG) that contain services and characteristics. Services are something like a container that contain similar data and the characteristics then contain the actual data. For example, the Blood Pressure Profile contains the Device Information Service, i.e. This service only contains information that relates to the device. And if I want to access very specific information, e.g. Model number, I have to use Characteristics. Is my understanding correct so far?

So, I have connected the above-mentioned developer board with a sensor and would like to send this data to a PC via Bluetooth Low Energy. I saw that there is, among other things, the Nordic UART service, which contains an RX and TX characteristic. What I do not understand now is: Are all the services stored in a profile, if so what is the name of the profile? Secondly, a service encapsulates information that is similar, but the Nordic UART service has no information, the information is in my sensor, and I apparently only use the Nordic UART service to send this data to the PC. Can someone explain this to me more precisely with the Nordic UART service, the RX and TX Characteristic? I did some research on the internet, but I don't understand the whole thing (I'm a newcomer to this area). Thank you so much!

[awneil]

A beginner's tutorial on BLE Services:

https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-services-a-beginners-tutorial

Example using NUS:

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v16.0.0/ble_sdk_app_nus_eval.html

SpaceToon said:

the Nordic UART service has no information, the information is in my sensor, and I apparently only use the Nordic UART service to send this data to the PC

Exactly - just like a real UART, it is just a way to transport arbitrary, unstructured data.

[SpaceToon]

Thank you - but how can I find the name of the Profile, that is used here? So the Blood Pressure profile consists of Blood Pressure Service and Device Information Service. My Device, the Adafruit DevBoard with the nordic CBLE Chip, has 5 Services (e.g. Nordic UART Service, Device Information...). But under what Profile name are they available? 

[awneil]

NUS = Nordic UART Service - It is just a Service, with a set of defined Characteristics.

It is a proprietary Service - so it won't appear in any Standard Profiles.

What do you mean by, "CBLE" ?

[Karl Ylvisaker]

Hello,

I'm a newcomer to this area

Welcome!
Do not hesitate to ask questions if things are unclear.

To get started working with the BLE concepts and to get some practical experience with using advertising, services and characteristics I would highly recommend going through the tutorial that @Awneil already mentioned! Its a great way to familiarize yourself with the subject. The learning curve might seem steep at times, but you'll get the hang of it in notime!
If you would like to watch a video on the subject, I would recommend this one for familiarizing yourself with the BLE terminology and usage.

Please let me know if things are still unclear with regards to your initial ticket question,

Best regards,
Karl