CC2564_15 Datasheet, PDF (20/47 Pages) Texas Instruments – Bluetooth® and Dual-Mode Controller

CC256x
SWRS121D – JULY 2012 – REVISED JANUARY 2014
www.ti.com
3.5.3.6 Two-Channel Bus Example
Figure 3-15 shows a 2-channel bus in which the two channels have different word sizes and arbitrary
positions in the bus frame. (FT stands for frame timer.)
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
Figure 3-15. 2-Channel Bus Timing
CH2 data
length = 8
Fsync period = 128
Fsync length = 1
twochpcm_swrs064
3.5.3.7 Improved Algorithm For Lost Packets
The device features an improved algorithm to improve voice quality when received voice data packets are
lost. There are two options:
• Repeat the last sample: possible only for sample sizes up to 24 bits. For sample sizes larger than 24
bits, the last byte is repeated.
• Repeat a configurable sample of 8 to 24 bits (depending on the real sample size) to simulate silence
(or anything else) in the bus. The configured sample is written in a specific register for each channel.
The choice between those two options is configurable separately for each channel.
3.5.3.8 Bluetooth and Codec Clock Mismatch Handling
In Bluetooth RX, the device receives RF voice packets and writes them to the codec interface. If the
device receives data faster than the codec interface output allows, an overflow occurs. In this case, the
Bluetooth has two possible modes of behavior:
• 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 the coprocessor to perform the LE or ANT
functionality. The CC2560B and CC2564B devices use the 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).
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