BLE Introduction and Principle

1. BLE? is the abbreviation for Bluetooth?Low?Energy, also known as Bluetooth 4.0, is mainly used to realize the continuous connection between mobile smart terminals and peripheral accessories, and is a short-range wireless communication technology with extremely low power consumption, and the effective transmission distance has been enhanced to more than 100 meters.

2. BLE devices are divided into single-mode and dual-mode, dual-mode referred to as BR, trademarked as Bluetooth?Smart?Ready, single-mode referred to as BLE or LE, trademarked as Bluetooth?Smart.

3. Dual-mode compatibility with the traditional bluetooth, you can and the traditional bluetooth communication, but also with the BLE communication, commonly used in cell phones, android4.0, android4.0, android4.0, android4.0, android4.0, android4.0. Single-mode can only communicate with BR and single-mode devices, can't communicate with traditional Bluetooth, due to low power consumption and long standby time, so it is commonly used in the smart devices of bracelet. This can explain the difference between BLE on a cell phone and BLE on a device such as a bracelet.

B(device) ?P(phone) PM(power management)

The current BLE SDK has two basic states: broadcast state (advertising state) and connection state (connection state), and when added to the low power (power management, abbreviated as PM), the BLE SDK has two basic states: broadcast state (advertising state) and connection state (connection state), and when added to the low power (power management, abbreviated as PM), the BLE SDK has two basic states: broadcast state (advertising state) and connection state (connection state), and when added to the low power (power management, abbreviated as PM), the BLE SDK has two basic states: broadcast state (advertising state) and connection state (connection state). management (PM) management, a deepsleep state is added.

1. B is in the broadcast state after powering on, and sends out broadcasts continuously

2. If a connection request is initiated by p during the broadcast process, B and p establish a connection, and start to maintain the connection state and communicate with each other.

3. In the connection state, there are three cases to return to the broadcast state (i.e., often encountered disconnection during the connection process):

(1) P discovers anomalies, sends a stop command to B, and takes the initiative to disconnect.

(2) B sends a stop command to P and actively disconnects.

(3) B's RF receives a packet abnormally or P sends a packet abnormally, resulting in B not receiving a packet for a long time, triggering BLE's servicing timeout, and B disconnects and returns to the broadcast state. The BLE will be disconnected and return to the broadcasting state.