CC256X Datasheet, PDF (20/51 Pages) Texas Instruments – Bluetooth® Smart Ready Controller

CC256x
SWRS121C – JULY 2012 – REVISED OCTOBER 2013
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3.5.3 Digital Codec Interface
The codec interface is a fully programmable port to support seamless interfacing with different PCM and
I2S codec devices. The interface includes the following features:
• Two voice channels
• Master and slave modes
• All voice coding schemes defined by the Bluetooth specification: linear, A-Law, and μ-Law
• Long and short frames
• Different data sizes, order, and positions
• High flexibility to support a variety of codecs
• Bus sharing: Data_Out is in Hi-Z mode when the interface is not transmitting voice data.
3.5.3.1 Hardware Interface
The interface includes four signals:
• Clock: configurable direction (input or output)
• Frame_Sync and Word_Sync: configurable direction (input or output)
• Data_In: input
• Data_Out: output or 3-state
The CC256x device can be the master of the interface when generating the clock and the frame-sync
signals or the slave when receiving these two signals.
For slave mode, clock input frequencies of up to 15 MHz are supported. At clock rates above 12 MHz, the
maximum data burst size is 32 bits.
For master mode, the CC256x device can generate any clock frequency between 64 kHz and 4.096 MHz.
3.5.3.2 I2S
When the codec interface is configured to support the I2S protocol, these settings are recommended:
• Bidirectional, full-duplex interface
• Two time slots per frame: time slot-0 for the left channel audio data; and time slot-1 for the right
channel audio data
• Each time slot is configurable up to 40 serial clock cycles long, and the frame is configurable up to 80
serial clock cycles long.
3.5.3.3 Data Format
The data format is fully configurable:
• The data length can be from 8 to 320 bits in 1-bit increments when working with 2 channels, or up to
640 bits when working with 1 channel. The data length can be set independently for each channel.
• The data position within a frame is also configurable within 1 clock (bit) resolution and can be set
independently (relative to the edge of the Frame_Sync signal) for each channel.
• The Data_In and Data_Out bit order can be configured independently. For example; Data_In can start
with the most significant bit (MSB); Data_Out can start with the least significant bit (LSB). Each
channel is separately configurable. The inverse bit order (that is, LSB first) is supported only for
sample sizes up to 24 bits.
• It is not necessary for Data_In and Data_Out to be the same length.
• The Data_Out line is configured to Hi-Z output between data words. Data_Out can also be set for
permanent Hi-Z, regardless of data out. This allows the CC256x device to be a bus slave in a
multislave PCM environment. At power up, Data_Out is configured as Hi-Z.
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