Analog Devices SHARC ADSP-21375, Руководство пользователя

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ADSP-21375 EZ-KIT Lite Evaluation System Manual 2-11
ADSP-21375 EZ-KIT Lite Hardware Reference
Codec Setup Switch (SW3)
The codec setup switch (
SW3
) can be used to change the routing of some
signals going to the AD1835A codec and to set up the communication
protocol of the codec.
SW3
positions 1 and 2 determine the clock routing for the audio oscillator
to the codec and to the processor. Figure 2-5 illustrates how the switch
positions 1 and 2 connect on the board. In the default position, route the
DAI_P17
pin to
DAI_P6
(in software) to clock the AD1835A codec.
SW3
position 3 determines if the AD1835A device is a master or a slave. If
the AD1835A is a master, the device’s serial interface generates the frame
sync and clock signals necessary to transfer data. When the device is a
slave, the processor must generate the frame sync and clock signals. By
default, position 3 is
ON
, and the AD1835A codec generates the control
signals.
SW3
position 4 disconnects the AD1835A codec’s
ADC_DATA
pin from the
DAI interface. This is useful when the DAI interface connects to another
device.
Figure 2-5. Audio Clock Routing
ADSP-21375 Processor AD1835A Codec
DAI_P6
DAI_P17
MCLK
12.288 MHz
OSC
SW3.1
SW3.2