readme.txt

ADI 公司的DSP ADSP21369 EZ-KIT LITE开发板的全部源代码

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Example:  Talkthru W-SRC_Digital In-Analog Out (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 (two stereo pairs 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.

There are two clock domains in this project.
The first is derived from the SPDIF input stream. Each interrupt reads a single
24-bit sample (alternating left and right) using SPORT0A and immediately writes
the same value to SPORT1A. All audio is transmitted in I2S mode.

The second clock is provided by the AD1835. Each interrupt reads a single 24-bit
sample (alternating left and right) using SPORT2 and immediately writes the same
value to both the A and B data channels of SPORT3 and SPORT4. All audio is
transmitted in I2S mode.

The ADC data is being received on SPORT2B while the SPDIF is being received on 
SPORT2A. The ADC data is being copied to DACs 1 & 2, and the SPDIF data is being 
copied to DACs 3 & 4.

An Asynchronous SRC is being used to convert the data between the two clock
domains so that the input data from the SPDIF receiver can be sent to the DACs.
This setup will work for encoded data if the decoding takes place in the SPORT0
interrupt.

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Instructions: Download the executable to the EZ-KIT.  There are no user
controls or visual outputs.

Required Switch Settings: SW3 - 1=Off, 2=On, 3=On, 4=On
                            (this is the default setting)
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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 W-SRC_Digital In-Analog Out.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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