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Bluetooth Accelerator (BTA)
Single-Slot Packet
2
1
L_CH
FLOW
72
Bluetooth
Packet
Access Code
AM_ADDR
3
The packet type information is available from the payload header field, which is the first one or two bytes
of the payload depending on the packet type. The packet header and length information can be determined
from this field.
The PACKET_HEADER and PAYLOAD_HEADER Registers hold header information. In transmit
mode, these registers are written. In receive mode, these registers are read.
Each of the subsections of the Pipeline Processor are discussed in detail in the next sections.
16.3.1.3.1 HEC/CRC Generator and Checker
The Header Error Correction (HEC) and Cyclic Redundancy Check (CRC) unit can be enabled or disabled
by software. If enabled, the unit operation depends on the direction of the bit stream transfer.
Transmit Function—When a Bluetooth packet is to be transmitted by the unit, the HEC/CRC unit
performs the following sequence of actions:
1. Generate the HEC for the packet header.
2. Generate the payload CRC based on the length supplied by software.
3. The software must specify the HEC/CRC initialization word by writing the initialization
word to the HECCRC_CONTROL register. The initialization word is derived from the
Bluetooth clock. The generation of the initialization word is described in the Specification
of the Bluetooth System, version 1.1.
4. Raise a flag to the sequencer after the last CRC bit has been encoded. This is used for zero
stuffing (when necessary) before FEC encoding.
Receive Function—When a Bluetooth packet is received, the HEC/CRC unit performs the following
sequence of actions:
1. Extract the type and length information from the bit stream. This information is used to
control the remaining parts of the bit stream.
The type information is available from the packet header and length information fields in the
payload header field, which is the first one or two bytes of the payload, depending on the packet
16-8
OR
5
LENGTH
L_CH
54
Payload
Header
Header
TYPE
FLOW
ARQN
SEQN
4
1
1
Figure 16-3. Bluetooth Packet Format
MC9328MX1 Reference Manual
Multi-Slot Packet
2
1
9
FLOW
LENGTH
0 to 2745
Payload
HEC
1
8
4
Undefined
MOTOROLA
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