User's Manual

Enhanced Class 1 Bluetooth v2.1 Module
User’s Guide
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CONN-GUIDE-BT740_v0.2
12.2 Logical Packet Format
The format of the HDP logical packet is as follows:
LEN
PACKET_TYPE
DATA
2 bytes
1 byte
N bytes
LEN is set to N+3 and big endian, so that the first byte of LEN sent on the wire is the MSB. The DATA
field structure depends on the logical packet type specified by PACKET_TYPE and the following
subsections describe the types of packets available at the time of writing.
12.2.1 Packet Type: Attribute Value
This logical packet sends to the host as a result of processing the CMD_HDP_ATTRIBUTE_READ
command in either the agent or manager roles.
For this logical packet type the PACKET_TYPE field sets to 0x00 and the DATA field consists of 4 fields
as follows:
Agent Handle
Attr Nominal Code
Attr Qualifier Field
Attr Value
2 bytes
2 bytes
2 bytes
N bytes
The ‘Agent Handle’, ‘Attr Nominal Code’ and ‘Attr Qualifier ID’ fields are all 2 byte fields in big endian
format (MSB first) and echo from the CMD_HDP_ATTRIBUTE_READ command, and ‘Attr Value’ is the
actual value of the attribute.
Calculate the length of N by subtracting 9 from the LEN field of the logical packet.
12.2.2 Packet Type: Scan Report
This logical packet sends to the host in a manager role as a result of scan report arriving from an agent.
For this logical packet type the PACKET_TYPE field sets to 0x01 and the DATA field consists of multiple
fields as follows:
Agent Handle
Person ID
Num of Objects
Data Lists
2 bytes
2 bytes
1 byte
N bytes
The ‘Agent Handle’ and ‘PersonID’ fields are 2 byte fields in big endian format (MSB first), ‘Num of
Objects’ is a one byte field which specifies the number of objects, and the field ‘Data Lists’ consists of
multiple composite fields structured as follows:
Field Type
Data
1 byte
N bytes
‘Field Type’ can be 0x00 for ‘OBJECT HANDLE’ and 0x01 for ‘ATTRIBUTE TAG/VALUE’, and the size of
the ‘Data’ field depends on the Field Type. The available Field Types/Data are described in the following
sections.