on
2021-04-13
3:45 AM
- edited on
2025-08-01
5:43 AM
by
Laurids_PETERSE
This article details the Bluetooth LE packet formats for different applications from IoT to Automotive.
The Bluetooth LE protocol stack is composed by a Host and a Controller layer organized as per the picture below:
ADV_IND shall be used in connectable and scannable undirected advertising events.
ADV_NONCONN_IND shall be used in non-connectable and non-scannable undirected advertising events.
ADV_SCAN_IND shall be used in scannable undirected advertising events.
More information available here
The PDU shall be used in connectable directed advertising events. More info available here.
AA: The link layer connection's access address
CRCInit: Initialization value for the CRC calculation
WinSize: The transmitWindowSize value
WinOffset: The transmitWindowOffset value
Interval: Connection interval of data connection
Latency: The connSlaveLatency value
Timeout: The connSupervisionTimeout value
ChM: Channel map which indicates Used and Unused data channels. LSB represents data channel index 0. A bit value of 0 indicates that the channel is Unused and a bit value of 1 indicates that the channel is Used.
Hop: hopIncrement used in the data channel selection algorithm. Random value in the range of 5 to 16.
SCA: used to determine the worst case Master's sleep clock accuracy.
Useful links to know more about iBeacon advertising packet structure , iBeacon and BLE generic access profile
More info here on Eddystone protocol specifications and service
Packets take between 44 and 2120 μs to transmit.
LLID: Indicates whether the packet is an LL Data PDU or an LL Control PDU
NESN: Next expected Sequence Number
SN: Sequence Number
MD: More data
RFU: Reserved for future use
LLID: Indicates whether the packet is an LL Data PDU or an LL Control PDU
NESN: Next expected Sequence Number
SN: Sequence Number
MD: More data
RFU: Reserved for future use