readme.txt

对ADSP21369的原理图和测试程序进行搜集

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Example:  Talkthru Digital In-Analog Out External PLL (P8=Input, J5 and P7=Output)
Target:   ADSP-21369
Date:     July 29, 2005
Tools:    VisualDSP++ 4.0
Hardware: ADSP-21369 EZ-KIT LITE
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Multichannel talk-through (stereo in -> four stereo pairs out)

TalkThrough reads audio samples from the on-chip SPDIF receiver and it
passes the unmodified data through to the four DACs of the AD1835.
Each interrupt reads a 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.  An MCLK is derived
from the SPDIF input stream, as well as the bit clock and the frame sync. The
MCLK is passed through the external Analog PLL (U38) to remove the jitter
that is caused by the receiver's built-in digital PLL. Using this analog PLL
is only necessary for DACs that are sensitive to jitter on the MCLK being used.
All are driven to the Codec.

The SPDIF data is sent to all four DACs.
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Instructions: Download the executable to the EZ-KIT.  There are no user
controls or visual outputs.

All switches on SW3 should be OFF.
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Source Files contained in this directory:
21369_IVT.asm          Interrupt vector table code
ADSP-21369-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
initSRU.asm            Initializes the SRU & DAI/DPI pins
initPLL_SDRAM.asm      Configures the DSP to run at CCLK= 393.21 MHz & SDCLK= 157.28 MHz.
initSPORT.asm          Initializes the transmit and receive serial ports
initSPDIF.asm          Initializes the SPDIF receiver
SPORTisr.asm           The interrupt service routine
Talkthru Digital In-Analog Out External PLL.dpj    VisualDSP Project File
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Dependencies contained in VisualDSP++ default include path:
def21369.h             Header with constants for the SHARC
SRU.h                  Macro to simplify programming the SRU & DAI/DPI pins
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Analog Devices, Inc.
DSP Division
One Technology Way
Norwood, MA 02062

(c) 2005 Analog Devices, Inc.  All rights reserved.
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