readme.txt

audio talktrough code. platform bf533 + audio card.

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Talkthrough for the ADSP-BF537 EZ-KIT Lite with Audio EZ-Extender

Analog Devices, Inc.
Audio Rendering Technology Center Team
1741 Technology Driver
San Jose, CA 95110

Date Created:	08/25/2005

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This directory contains an example ADSP-BF537 program that demonstrates the
communication between the AD1938 codec and the ADSP-BF537 processor using the
system service library and device driver model.  The AD1938 codec resides on the Audio 
EZ-Extender card that attaches to the ADSP-BF537 EZ-Kit.  The SPI port provides the control 
link, and SPORT1 is used for audio transmission.

Files contained in this directory:

readme.txt              this file
main.c                  C file containing the main loop and audio handling function
talkthrough.c           C file containing routines for audio data processing
talkthrough.h           C header file for talkthrough.c
AudioDriver.c           C file containing the initialization and termination functions for 
			the device drivers
AudioDriver.h           C header file for AudioDriver.c
adi_AudioEzExtender.c   C file of the virtual device driver for the Audio EZ-Extender
adi_AudioEzExtender.h   C header file for the Audio EZ-Extender driver
Talkthrough_BF537_AudioEZExtender.dpj      VisualDSP++ project file

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CONTENTS

I.	FUNCTIONAL DESCRIPTION
II.	IMPLEMENTATION DESCRIPTION
III.    HARDWARE/SOFTWARE CONFIGURATION
IV.	OPERATION DESCRIPTION

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I.    FUNCTIONAL DESCRIPTION

The Talkthru example demonstrates the initialization of the device drivers to configure the
AD1938 codec and establish a link between the ADSP-BF537 and the codec.

The audio EZ-Extender device driver is a virtual driver that resides on top of the AD1938 
driver to allow the user to easily configure the EZ-Extender with various audio modes.  
Currently this driver only supports the analog codec AD1938.  The digital codec ADAV801 is 
not supported and should use the default configuration.

The Audio EZ-Extender driver uses the AD1938 driver to simply set up the SPI port to 
configure both the AD1938 codec A and the AD1938 codec B in TDM 16 channel mode (8 channels 
for each SPORT primary/secondary).  SPORT1 is then setup to receive and transmit audio 
samples from the codec.  Input audio samples from the AD1938 are stored in the processor's 
receive buffer, using DMA.  The samples are processed by the ADSP-BF537 and placed into the 
transmit buffer.  In turn, the transmit buffer is used to transmit data to the AD1938. 
This results in a simple talk-through where data is moved in and out of the processor without 
performing any computations on the data.

This example has also a framework that can be used to easily process the data in 
non-interleaved sequential format.  Talkthrough.c contains a conversion function for each 
input/output audio channel.

The existing configuration sets the codec at 48khz sampling rate.  Audio samples are received
from the L1, R1, L2, R2, L3, R3, L4, R4 input channels of the ADC RCA jack on the EZ-Extender, 
and transmitted through the L1, R1, L2, R2, L3, R3, L4, R4 output jacks.  


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II.   IMPLEMENTATION DESCRIPTION

The Initialization module does the following.

1. Initializes the system service libraries and the device manager.
2. Initializes the audio EZ-Extender driver which configures AD1938 driver accordingly, and
    then sets up the SPI and SPORT drivers.
3. Based on the audio mode index, it calls AD1938 driver's control API to configure the 
    AD1938 codec and ADAV801.
4. Configures SPORT1 in TDM mode and sets up DMA circular buffers for the SPORT through the 
    AD1938 driver.
5. Intializes the callback function for the DMA interrupt handler to process audio data.


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III. HARDWARE/SOFTWARE CONFIGURATION

-----------------------------------------------------
 HARDWARE 
-----------------------------------------------------
ADSP-BF537 EZ-KIT LITE REV 1.1 or later
BLACKFIN Audio EZ-EXTENDER REV 1.1 or later
Audio source (e.g: CD-player) with RCA jack cable
Speaker/Headphone with RCA jack input.

-----------------------------------------------------
 AUDIO EZ-EXTENDER POPULATED JUMPERS
-----------------------------------------------------
JP1.7/8 (SPORT_SEL) unpopulate
JP1.1/2 (BF537_SEL) populate
JP1.5/6 (SPORT1_EN) populate
JP2.SCLK3 selected
SW1~SW4 all OFF

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ADSP-BF537 EZ-KIT LITE SETTINGS:
-----------------------------------------------------

Note: Depending on the revision level of your 
ADSP-BF537 EZ-KIT some of these settings will not 
exist on the board.  You can simply disregard these 
settings.  The lack of these components will have
no effect on the operation of your ADSP-BF537 EZ-KIT.

OFF = SW1, SW2, SW3, SW4, SW5, SW7, SW8, SW12 
OFF = JP7, JP2, JP8, JP6, JP9
ON = SW6, JP1, JP4, JP5, 
JP10.2/3 populate
JP3.1/2 populate
SW16 = Set for default 1 (Boot from on board flash)

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SOFTWARE:
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PC with the following specification
- 166 MHz or higher Intel Pentium㈢ or compatible processor
- Minimum of 32 megabytes of RAM
- Windows 98, Windows 2000, or Windows XP
- One available USB slot

VisualDSP++ 4.0 (updated August or later)
- Session for BlackFin ADSP-BF537 through emulator or debug agent


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IV.  OPERATION DESCRIPTION

- Plug the Audio EZ-Extender card onto the ADSP-BF537 EZ-Kit lite's expansion slot
- Configure hardware as described above
- Connect an input source (such as a CD-player) to the Audio input jack and 
  an output source (such as a speaker) to the Audio output jack.  
  See the Audio EZ-Extender User's Manual for more information on input/output jack layout.
  Audio input and output channels are set up as follows.

        input        output
         L1    --->  L1
         R1    --->  R1
         L2    --->  L2
         R2    --->  R2
         L3    --->  L3
         R3    --->  R3
         L4    --->  L4
         R4    --->  R4

- Open the project "Talkthrough_BF537_AudioEZExtender.dpj" in an ADSP-BF537 EZ-KIT Lite session 
  in the VisualDSP Integrated Development Environment (IDDE).
- Under the "Project" tab, select "Build Project" (program is then loaded 
  automatically onto the processor).
- Select "Run" from the "Debug" tab on the menu bar of VisualDSP.
- Listen to the operation of the talkthrough.