1、LMP層整體架構
藍牙controller中整體架構如下所示,HCI層、LMP層、Baseband層以及LC等各部分。
對於LMP來說,簡化版的結構如下所示,LM模塊和LC模塊交互完成host和controller之間的命令交互。
2、數據包格式
LMP數據包採用DM1包,並且長度固定不能夠超過DM1數據包的長度。只有在HV1數據包的SCO鏈路中,並且數據長度小於9bytes時,採用DV數據包。
3、LMP支持的feature特性。
LMP特性總共有三個page頁,分別是page0、page1和page2,多數設備只支持page0頁特性。在page0頁中,每個bit爲代表一個特性,1表示支持此特性,0表示不支持此特性,其中,page0中總共有8bytes64個特性。
No.
|
Supported feature
|
Byte
|
Bit
|
|
0
1
2
3
4
5
6
7
|
3 slot packets
5 slot packets
Encryption
Slot offset
Timing accuracy
Role switch
Hold mode
Sniff mode
|
0
0
0
0
0
0
0
0
|
0
1
2
3
4
5
6
7
|
|
8
9
10
11
12
13
14
15
|
Park state
Power control requests
Channel quality driven data rate (CQDDR)
SCO link
HV2 packets
HV3 packets ì-law log synchronous data
A-law log synchronous data
|
1
1
1
1
1
1
1
1
|
0
1
2
3
4
5
6
7
|
|
16
17
18
19
20
21
22
23
|
CVSD synchronous data
Paging parameter negotiation
Power control
Transparent synchronous data
Flow control lag (least significant bit)
Flow control lag (middle bit)
Flow control lag (most significant bit)
Broadcast Encryption
|
2
2
2
2
2
2
2
2
|
0
1
2
3
4
5
6
7
|
|
24
25
|
Reserved
Enhanced Data Rate ACL 2 Mb/s mode
|
3
3
|
|
|
26
27
28
29
30
31
|
Enhanced Data Rate ACL 3 Mb/s mode
Enhanced inquiry scan
Interlaced inquiry scan
Interlaced page scan
RSSI with inquiry results
Extended SCO link (EV3 packets)
|
3
3
3
3
3
3
|
2
3
4
5
6
7
|
32
33
34
35
36
37
38
39
|
EV4 packets
EV5 packets
Reserved
AFH capable slave
AFH classification slave
BR/EDR Not Supported
LE Supported (Controller)
3-slot Enhanced Data Rate ACL packets
|
4
4
4
4
4
4
4
4
|
0
1
2
3
4
5
6
7
|
40
41
42
43
44
45
46
47
|
5-slot Enhanced Data Rate ACL packets
Sniff subrating
Pause encryption
AFH capable master
AFH classification master
Enhanced Data Rate eSCO 2 Mb/s mode
Enhanced Data Rate eSCO 3 Mb/s mode
3-slot Enhanced Data Rate eSCO packets
|
5
5
5
5
5
5
5
5
|
0
1
2
3
4
5
6
7
|
48
49
50
51
52
53
54
55
|
Extended Inquiry Response
Simultaneous LE and BR/EDR to Same Device Capable
Reserved
Secure Simple Pairing
Encapsulated PDU
Erroneous Data Reporting
Non-flushable Packet Boundary Flag
Reserved
|
6
6
6
6
6
6
6
6
|
0
1
2
3
4
5
6
7
|
56
|
Link Supervision Timeout Changed Event
|
7
|
0
|
57
58
59
60
61
62
63
|
Inquiry TX Power Level
Enhanced Power Control
Reserved
Reserved
Reserved
Reserved
Extended features
|
7
7
7
7
7
7
7
|
1
2
3
4
5
6
7
|
|
|
|
|
|
|
|
Page1和page2頁不在此詳細描述,詳見藍牙核心協議文檔。
4、LMP常用控制命令
LMP支持的控制命令可以分爲如下6個類別,連接控制類、安全類、信息請求類、角色切換類、操作模式類(sniff模式等)、本地傳輸類(sco/esco)和測試類。
連接過程的LMP命令如下
請求支持命令。
請求操作模式命令
模式切換過程activity mode《==》sniff mode《==》sniff subrating mode。
詳細命令不在此介紹,詳見藍牙core文檔。