/*================================================================================
Example: Sample Playback
Target: ADSP-21262
Date: September 26, 2003
Tools: VisualDSP++ 3.0 SP1
Hardware: ADSP-21262 EZ-KIT LITE
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This example plays back a mono, 16-bit, 48kHz audio sample stored in the
parallel flash while blinking LEDs by writing to a memory-mapped latch. As the
sample is played back, the balance is swept from right to left by adjusting the
gain on the L and R channel in SW.

SPORT2 is used to send samples to the CODEC using interrupts.  The samples are
played using an I2S connection to the CODEC, so a new sample is only required
on alternating serial port interrupts.  Because the FLASH and LED LATCH are on
the same bus, the two subroutines must first check for any PP activity before
changing any parameters.

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Instructions: This demo runs with all switches and jumpers in in their default
positions.  If a sample is already in the FLASH, then operation only requires
loading Sample Playback.dxe and running it. The default location of the audio
sample in the flash is 0x01040000.

To program the flash with these samples, build and run the project in the Sample
Playback Flash Programmer directory.

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Source Files contained in this directory:

Subdirectories:
./Sample Playback Flash Programmer - directory containing a Flash Programmer
                      project to program the two samples and the loader file
                      created in this project.

./samples           - directory containing audio source and matlab script to
                      create new samples from .WAV files.

Files:
Sample Playback.dpj - VisualDSP Project file
ad1835.h            - definitions used for initializing codec
CTalkThrough.ldf    - linker description file
global_vars.c       - global variables used across subroutines
init1835viaSPI.c    - uses DMA to write to the 1835's control registers
initDAI.c           - a macro in SRU.h routes SRU signals (see file for detail)
initSPORT.c         - initialize SPORT2 to communicate w/ CODEC
SPORTisr.c          - handle SPORT2 int., determine if L or R sample needed
Sample Playback.h   - project settings such as LED sweep rate, sample size, etc.
LED.asm             - subroutine which writes one new value to the LED latch
main.c              - initializes system then stays in loop to synchronize the
                      LED sweeping with the sample playback
process_samples.c   - Adjust L/R gain so balance matches LED position
read_flash.c        - Fetches one sample from the parallel flash.  This is
                      called every other sport interrupt.
sweep.c             - subroutine which controls LED status - this file calls
                      the subroutine in LED.asm, and is frequently interrupted
                      by the SPORT2 interrupt to fetch a new sample.
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Dependencies contained in VisualDSP++ default include path:
SRU.h                    Header file with DAI definitions
def21262.h               Header file with generic definitions
*******************************************************************************
Analog Devices, Inc.
DSP Division
One Technology Way
Norwood, MA 02062

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