Does anyone know why bluenrg_2 adds +2 to the feature value when subscribing to it?

mfc4143

yibin_cai

The essence of subscription is to write 0x0100 to the attribute value representing the "characteristic descriptor".

A feature with subscription properties needs to be described by at least three properties:

0x000A Feature declaration attributes // I am a feature

0x000B Characteristic value attribute // The value of this characteristic

0x000C Feature descriptor attributes // Some attributes of this feature

The feature descriptor handle needs to be offset by 2 relative to the feature declaration.