One minute to understand BLE advertising data package

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One minute to understand BLE advertising data package
BLE =》 BTLE （Bluetooth Low Energy）
1. How to capture BLE advertising data (full channel at 37,38,39 simutanueously)
   * Hardware：One BLE device (has feature of advertising);
         One HOLLONG BLE SNIFFER
   * Software：Hollong BLE sniffer software 
        Download：

http://www.viewtool.com/index.ph ... 0option=com_content

2. Profile
   BLE Advertising package introduction：
   * Payload data maximum length： 37 bytes
   * Advertising channels：37，38，39 （hopping）
   * Transmission power：usually 0dBm, Maximum 10dBm      


   In each section below, pay attention on blue color marked portion (the raw data captured) and related data interpret portion（data 
interpretation）


3. Access Address
   It is fixed length (4 bytes) and fixed data (0x8e89bed6) used for master device access address identification.



4. Header Info
   Fixed 2 bytes：used by 16 bits
   BIT[0:3]：Advertising package（PDUs) type，there are following PDU Types：

        PDU Type
        b3b2b1b0 Packet Name
        0000 ADV_IND： connectable undirected advertising event
        0001 ADV_DIRECT_IND：connectable directed advertising event
        0010 ADV_NONCONN_IND：non-connectable undirected advertising event
        0011 SCAN_REQ：scan request
        0100 SCAN_RSP: scan response
        0101 CONNECT_REQ：connection request
        0110 ADV_SCAN_IND：scannable undirected advertising event
        0111-1111 Reserved


   BIT[4:5]：Reserved
   BIT[6]：RxAdd
   BIT[7]：TxAdd
   BIT[8:13]：advertising data length （Maximum 37 bytes)
   BIT[14:15]：Reserved


5. MAC Address
   Fixed 6 bytes



6. Advertising data：flag field
   02 01 06
   02：field length 2 bytes
　 01: as flag
   06：BIT1,BIT2 = 1， based on definition below, interept as：
　　　* LE General Discoverable Mode
      * BR/EDR Not Supported (i.e. bit 37 of LMP Extended
Feature bits Page 0)

0 LE Limited Discoverable Mode
1 LE General Discoverable Mode
2 BR/EDR Not Supported (i.e. bit 37 of LMP Extended
Feature bits Page 0)
3 Simultaneous LE and BR/EDR to Same Device Capa-
ble (Controller) (i.e. bit 49 of LMP Extended Feature
bits Page 0)
4 Simultaneous LE and BR/EDR to Same Device Capa-
ble (Host) (i.e. bit 66 of LMP Extended Feature bits
Page 1)
5..7 Reserved 


7. Service tag field
   03 03 02 18
   03：field length 2 bytes
　 03: service tag field
   02 18：=》18 02 => Immediate Alert Service



8. Device name field
   0e 09 45 .... 6d 65
   0e: field length 14 bytes
   09：device name field
   45，。。。6d 65: device name (ASCII)



9. CRC：
      Fixed 3 bytes


Get complete Hollong BLE Sniffer captured data file:

Get advertising data format specification: