Analog Devices ADSP-2189M EZ-KIT Lite, Руководство пользователя

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Standard Operations
2-10 ADSP-2189M EZ-KIT Lite Evaluation System Manual
For more information about the AD73322 codec, go to
http://www.analog.com/Analog_Root/productPage/productH-
ome/0,2121,AD73322,00.html
.
AD73322 Codec Transmissions
After initialization, the AD73322 codec generates the clock used to trans-
fer data across
SPORT0
. The ADSP-2189M DSP initiates all transmissions
with the AD73322 device by sending a synchronization pulse. Even
though the AD73322 transmits the data clock, it may not be ready for
normal operation.
Initialization of the AD73322 codec is slightly different than that of other
codecs. Initialization is performed by sending at lest 8 and up to 16 con-
trol words contained in a circular buffer to the AD73322 codec. These
control words correspond to the AD73322s control registers
A
through
H
.This is usually done via the
SPORT0 TX
interrupt routine.
Once the codec is initialized, normal operation mode is entered, and the
TX
interrupt routine is never used again until the device is reset. During
normal operation, the
RX
interrupt of
SPORT0
is used. As each datum is
received from the codec, an interrupt is generated. This interrupt is the
SPORT0 RX
interrupt. Inside the
RX
interrupt, datum are moved from the
RX
buffer into the users buffer (generally, this is a circular buffer). At that
same
RX
interrupt, the codec is ready to receive data from the DSP. The
DSP then moves the data (from the users circular buffer) into
SPORT0s TX
buffer and clocks it into the codec.