CC256X Datasheet, PDF (23/51 Pages) Texas Instruments – Bluetooth® Smart Ready Controller

CC256x
www.ti.com
SWRS121C – JULY 2012 – REVISED OCTOBER 2013
• Allow overflow: if overflow is allowed, the Bluetooth continues receiving data and overwrites any data
not yet sent to the codec.
• Do not allow overflow: if overflow is not allowed, RF voice packets received when the buffer is full are
discarded.
3.5.4 Assisted Modes (CC2560B and CC2564B Devices)
The CC256x devices contain an embedded coprocessor (see Figure 1-1) that can be used for multiple
purposes. The CC2564 and CC2564B devices use this coprocessor to perform the LE or ANT
functionality. The CC2560B and CC2564B devices can use this coprocessor 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 1-1 for the modes of operation
supported by each device).
This section describes the assisted HFP 1.6 (WBS) and assisted A2DP modes of operation in the
CC2560B and CC2564B devices. These modes of operation minimize host processing and power by
taking advantage of the CC256x coprocessor to perform the voice and audio SBC processing required in
HFP1.6 (WBS) and A2DP profiles. This section also compares the architecture of the assisted modes with
the common implementation of the HFP1.6 and A2DP profiles.
The assisted HFP1.6 (WBS) and assisted A2DP modes of operation comply fully with the HFP1.6 and
A2DP Bluetooth specifications. For more information on these profiles, see the corresponding Bluetooth
Profile Specification (www.bluetooth.org/en-us/specification/adopted-specifications).
3.5.4.1 Assisted HFP1.6 (WBS)
The HFP1.6 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 is a modified version of the mandatory audio coding
scheme used in the A2DP profile with the parameters listed in Table 3-5.
Table 3-5. mSBC Parameters
Parameter
Channel mode
Sampling rate
Allocation method
Subbands
Block length
Bitpool
Value
Mono
16 kHz
Loudness
8
15
26
The assisted HFP1.6 mode of operation implements this WBS feature on the embedded CC256x
coprocessor. That is, the mSBC voice coding scheme and the PLC algorithm are executed in the CC256x
coprocessor rather than in the host, thus minimizing the host processing and power. One WBS connection
is supported at a time and WBS and NBS connections cannot be used simultaneously in this mode of
operation. Figure 3-16 shows the architecture comparison between the common implementation of the
HFP1.6 profile and the assisted HFP1.6 solution.
Copyright © 2012–2013, Texas Instruments Incorporated
Submit Documentation Feedback
Detailed Description
23