蓝牙BLE ATT剖析-- PDU
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一.Error Handling
Error Response
The Error Responseis used to state that a given request cannot be performed,and to provide the reason.
Note: The Write Command does notgenerate an Error Response
二.MTU Exchange
1.Exchange MTU Request
The Exchange MTU Requestis used by the client toinform the server of theclient’s maximum receive MTU size and requestthe server to respond with its
maximum receive MTU size.
2.Exchange MTU Response
The Exchange MTU Responseis sent in reply to a received Exchange MTURequest.
三.Find Information
1.Find Information Request
The Find Information Requestis used to obtain the mapping of attributehandles with their associated types. This allows a client to discover the list of
attributes and their types on a server
2. Find Information Response
The Find Information Responseis sent in reply to a received Find InformationRequestand contains information about this server
3.Find By Type Value Request
The Find By Type Value Requestis used to obtain the handles of attributes thathave a 16-bit UUID attribute type and attribute value.This allows the range of
handles associated with a given attribute to be discovered when the attribute
type determines the grouping of a set of attributes. Note: Generic Attribute
Profile defines grouping of attributes by attribute type.
4.Find By Type Value Response
The Find By Type Value Responseis sent in reply to a received Find By Type
Value Requestand contains information about this server
四.Reading Attributes
1.Read By Type Request
The Read By Type Requestis used to obtain the values of attributes where theattribute type is known butthe handle is not known
2.Read ByType Response
The Read By Type Responseis sent in reply to a received Read By TypeRequestand contains the handles and values of the attributesthat have been
read
3.Read Request
The Read Requestis used to request the serverto read the value of anattribute and returnits value in a Read Response
4.Read Response
The read response is sent in reply toa received Read Requestand containsthe value of the attribute that has been read
例:
5.Read Blob Request
The Read Blob Requestis used to request the server to read part of the valueof an attribute at a given offset and return a specific part of the value in a Read
Blob Response.
6.ReadBlob Response
The Read Blob Responseis sent in reply to a received Read Blob Requestandcontains part of the value of the attribute that has been read.
7.Read Multiple Request
The Read Multiple Requestis used to request the server to read two or morevalues of a set of attributesand return their values in a Read Multiple
Response. Only values that have a known fixed size can be read, with the
exception of the last value that can have a variable length. The knowledge of
whether attributes have a known fixed size is defined in a higher layer
specification.
8.Read Multiple Response
The read response is sent in reply toa received Read Multiple Requestandcontains the values of the attributes that have been read
9.Read by Group Type Request
The Read By Group Type Requestis used to obtain the values of attributeswhere the attribute type is known, the type of a grouping attribute as defined by
a higher layer specification,but the handle is not known.
10.Read by Group Type Response
The Read By Group Type Responseis sent in reply to a received Read ByGroup Type Requestand contains the handles and values of the attributes that
have been read
五.Writing Attributes
1.Write Request
The Write Requestis used to request the server to write the value of anattribute and acknowledge thatthis has been achieved in a Write Response
2.Write Response
The Write Responseis sent in reply to a valid Write Requestandacknowledges that the attribute has been successfully written
例:
3.Write Command
The Write Command is used to request the server to write the value of anattribute, typically into a control-pointattribute.
例:
4.Signed Write Command
The Signed Write Commandis used to request the serverto write the value of anattribute with an authentication signature, typically into a control-point attribute
六.Signed Write Command
The Signed Write Commandis used to request the serverto write the value of anattribute with an authentication signature, typically into a control-point attribute
七.ServerInitiated
1.Handle Value Notification
A server can send a notification of an attribute’s value at any time例:
2.Handle Value Indication
A server can send an indication of an attribute’s value3.Handle Value Confirmation
The Handle Value Confirmationis sent in response to a received Handle ValueIndicationand confirms that the client has received an indication of the given
attribute.
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