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Example: Talkthru Analog In-Out (AD1835...J4=Input, J5 and J6=Output)
Target: ADSP-21262
Date: September 19, 2003
Tools: VisualDSP++ 3.0 SP1
Hardware: ADSP-21262 EZ-KIT LITE
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Multichannel analog talk-through (stereo in -> four stereo pairs out)

TalkThrough reads audio samples from the stereo ADC of the AD1835 codec, and it
passes the unmodified data through to the four DACs.  Each interrupt reads a
single 24-bit sample (alternating left and right) using SPORT0 and immediately
writes the same value to both the A and B data channels of SPORT1 and SPORT2.
All audio is transmitted in I2S mode.  A 12.288 MHz clock is fed to the ADC as
MCLK, and the ADC generates the 64*48KHz bit clock and the 48 KHz frame sync.
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Instructions: Download the executable to the EZ-KIT.  There are no user
controls or visual outputs.  The four stereo output pairs are identical.
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Source Files contained in this directory:
21262_IVT.asm          Interrupt vector table code
ADSP-21262-EZKIT.ldf         Linker description file
ad1835.h               Header with constants for controlling the audio codec
main.asm               Calls initialization routines then waits for interrupts
init1835viaSPI.asm     Initializes the codec
initDAI.asm            Initializes the SRU & DAI pins
initSPORT.asm          Initializes the transmit and receive serial ports
SPORTisr.asm           The interrupt service routine
Talkthru Analog In-Out.dpj    VisualDSP Project File
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Dependencies contained in VisualDSP++ default include path:
def21262.h             Header with constants for the SHARC
SRU.h                  Macro to simplify programming the SRU & DAI pins
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Analog Devices, Inc.
DSP Division
One Technology Way
Norwood, MA 02062

(c) 2003 Analog Devices, Inc.  All rights reserved.
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