BLE Radio: Link Layer (LL)


The LL implements procedures to establish a reliable physical link, including:

  • Advertising: A state in which a BLE device broadcasts data to advertise that it is connectable and discoverable by nearby BLE devices
  • Scanning: A state in which a BLE device scans for nearby advertising BLE devices
  • Initiating and Creating Connections: The device that initiates the connection is called the LL Master; the device that accepts the connection is the LL Slave
  • Data Encryption: A hardware block that implements AES-128 encryption
  • Error Detection: A hardware block that implements a 24-bit cyclic redundancy check (CRC)
  • Adaptive frequency hopping (AFH): A process that enables BLE to adapt to the environment by avoiding channels that have poor signal strength or high error rates

The LL on PSoC 4 BLE is implemented in an integrated on-chip radio