Spectrum Digital TMS320DM365, Техническое описание

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Spectrum Digital, Inc
2-22 DM365 EVM Technical Reference
2.3 AIC3101 Interface
The EVM uses a Texas Instruments TLV320AIC3101 stereo codec for input and output
of audio signals. The codec samples analog signals on the microphone or line inputs
and converts them into digital data so it can be processed by the DSP. When the DSP
is finished with the data it uses the codec to convert the samples back into analog
signals on the line output so the user can hear the output.
The codec communicates using two serial channels, one to control the codec’s internal
configuration registers and one to send and receive digital audio samples. The I
2
C bus
is used as the AIC3101’s control channel. The control channel is generally only used
when configuring the codec, it is typically idle when audio data is being transmitted,
The DM365’s McBSP is used as the bi-directional data channel. All audio data flows
through the data channel. Many data formats are supported based on the three
variables of sample width, clock signal source and serial data format. The EVM
examples generally use a 16-bit sample width with the codec in master mode so it
generates the frame sync and bit clocks at the correct sample rate without effort on the
DSP side.
The codec is clocked via a 27 Mhz oscillator. The internal sample rate generator
subdivides the default system clock to generate common audio frequencies. The
sample rate is set by a codec register. The figure below shows the codec interface on
the DM365 EVM.
Figure 2-2, DM365 EVM CODEC Interface
DOUT
DIN
BCLK
WCLK
MIC IN
LINE IN
LINE OUT
HP OUT
McBSP
I2S Format
AIC33 Codec
Digital
Analog
MIC IN
LINE IN
LINE OUT
HP OUT
SCL
SDA
I
2
C
Control
SCL
SDA
I
2
C Format
DR
DX
CLKR
CLKX
FSR
FSX
Control Registers
ADC
DAC
AIC3101 Codec