bandpass.txt

ADSP-21160下的数字带通滤波器实现的汇编代码。 开发环境为 Visual Dsp 4.5++。

"ADSP-21160 EZ-KIT Lite bandpass FIR Demo"

Date Created:	4/11/02		Rev 1.0

This directory contains an example ADSP-21160 subroutine that demonstrates the 
initialization of the AC'97 communication link between SPORT0 on the ADSP-21160 
and the AD1881 stereo Codec.

This program also demonstrates 3 different bandpass filters.  

Files contained in this directory:

bandpass.dpj				VisualDSP project file	
bandpass.asm				Main Module
ISR_TABLE.asm				EZ-Kit ISR module
Codec_Processing_ISR.asm	Talkthru ISR Module
AD1881_INIT.asm				Initialization module
21160_EZKIT_Lite.ldf		Linker Description File 
AD1881_Registers.h			AD1881 Specific definitions
bandpass.h					Function Prototypes
SIMD_FIR_demo.asm			FIR Module
Filter_BP_4000_67.dat		bandpass coefficients
Filter_BP_2000_67.dat		bandpass coefficients
Filter_BP_800_67.dat		bandpass coefficients

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CONTENTS

I.	 FUNCTIONAL DESCRIPTION
II.	 IMPLEMENTATION DESCRIPTION
III. OPERATION DESCRIPTION


I.    FUNCTIONAL DESCRIPTION

The bandpass demo demonstrates the initialization of SPORT to establish
an AC'97 link between the ADSP-21160 and the AD1881 Codec.
 
This example simply exercises the SPORT0 interface.  SPORT0 is setup as a 
Slot-16 AC'97 interface to communicate with the AD1881.  Audio samples received
from the AD1881 are moved into the DSP's receive buffer, using DMA.  The samples are processed
by the ADSP-21160 and placed in the transmit buffer.  In turn, the transmit buffer is 
used to transmit data to the AD1881.  This results in a simple
talk-through where data is moved in and out of the DSP with out performing
any computations on the data.

The IRQ push buttons are then used to switch between the different filters and
standard talkthrough.


II.   IMPLEMENTATION DESCRIPTION

The Initialization module initializes:

1. The transmit and receive Multi-channel configuration. 
2. The transmit and receive DMA control registers and Auto-buffer registers.
3. The SPORT0 control registers.
4. The AD1881 Codec by writing to its control registers.
5. The bandpass FIR by pressing IRQ2 to switch between the different filtering
   coefficients.


III.  OPERATION DESCRIPTION

- Open a ADSP-21160 EZ-KIT Lite session in the VisualDSP Integrated Development Environment (IDDE).
- Open the project "bandpass.dpj" in the VisualDSP IDDE.
- From the "Project" menu, select "Build Project".
- Load "bandpass.dxe" into the ADSP-21160.
- Setup an input source (such as a radio) to the "LINE IN" and an output source (such as
  headphones) to the "LINE OUT" connectors of the EZ-KIT Lite.  See the ADSP-21160 EZ-KIT Lite
  User's Manual for more information on setting up the hardware.
- Select "RUN" from the "Debug" menu.
- Listen to the operation of the bandpass filters.
- IRQ2 is used to switch between the 3 different bandpass filters
- IRQ1 is used to switch between filtering and a standard talkthrough