I can't understand concept of control point..

[JoonDong]

I can't understand concept of control point..

Is it just one of charateristics?

So what are differences with other charateristics?

I heard that control point can be writable or notified, but cannot readable.

Is it right? I don't understand how unreadable value works.

[Petter Myhre]

A characteristic value could be a control point attribute, which per Bluetooth Core Specification 5.0, Vol 3, Part F, Section 3.2.6 is:

Attributes that cannot be read, but can only be written, notified or indicated arecalled control-point attributes. These control-point attributes can be used by higher layers to enable device specific procedures, for example the writing of a command or the indication when a given procedure on a device has completed.

You heard correct, and it is right.

Let me know if anything is still unclear.

[Petter Myhre]

Data received? Do you mean when a client writes to the attribute? Then the application on the server side will get a write event telling it that the attribute has been written to. Then it can react to the this event, but I guess it can also read it later. What is used in user code? I don't understand.