CC2564C Datasheet, PDF (33/52 Pages) Texas Instruments – CC2564C Dual-Mode Bluetooth Controller

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CC2564C
SWRS199A – APRIL 2016 – REVISED NOVEMBER 2016
Clock
FT
127 0 1 2 3 4 5 6 7 8 9
42 43 44
...
... _{127 0}
Fsync
Data_Out
MSB
LSB
bit bit bit bit bit bit bit bit bit bit bit
0 1 2 3 4 5 6 7 8 9 10
MSB
LSB
bit bit bit bit bit bit bit bit
...
0123 4567
Data_In
PCM_data_window
bit bit bit bit bit bit bit bit bit bit bit
0 1 2 3 4 5 6 7 8 9 10
bit bit bit bit bit bit bit bit
...
0123 4567
CH1 data start FT = 0
CH1 data length = 11
CH2 data
start FT = 43
NOTE: FT stands for frame timer.
Figure 6-14. 2-Channel Bus Timing
CH2 data
length = 8
Fsync period = 128
Fsync length = 1
twochpcm_swrs064
6.4.4 Assisted Modes
The CC2564C device contains an embedded coprocessor that can be used for multiple purposes (see
Figure 1-1). The CC2564C device uses the coprocessor to perform the LE functionality or to execute the
assisted HFP 1.6 (WBS) or assisted A2DP functions. Only one of these functions can be executed at a
time because they all use the same resources (that is, the coprocessor; see Table 3-1 for the modes of
operation supported by each device).
This section describes the assisted HFP 1.6 (WBS) and assisted A2DP modes of operation. These modes
of operation minimize host processing and power by taking advantage of the device coprocessor to
perform the voice and audio SBC processing required in HFP 1.6 (WBS) and A2DP profiles. This section
also compares the architecture of the assisted modes with the common implementation of the HFP 1.6
and A2DP profiles.
The assisted HFP 1.6 (WBS) and assisted A2DP modes of operation comply fully with the HFP 1.6 and
A2DP Bluetooth specifications. For more information on these profiles, see the corresponding Bluetooth
Profile Specification (www.bluetooth.org/en-us/specification/adopted-specifications).
6.4.4.1 Assisted HFP 1.6 (WBS)
The HFP 1.6 Profile Specification adds the requirement for WBS support. The WBS feature allows twice
the voice quality versus legacy voice coding schemes at the same air bandwidth (64 kbps). This feature is
achieved using a voice sampling rate of 16 kHz, a modified subband coding (mSBC) scheme, and a
packet loss concealment (PLC) algorithm. The mSBC scheme is a modified version of the mandatory
audio coding scheme used in the A2DP profile with the parameters listed in Table 6-3.
Table 6-3. mSBC Parameters
PARAMETER
Channel mode
Sampling rate
Allocation method
Subbands
Block length
Bitpool
VALUE
Mono
16 kHz
Loudness
8
15
26
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Detailed Description
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