readme.txt

使用ADSP-BF533的例子源代码

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ADSP-BF533 EZ-KIT Interface to ADC AD9244 Example

Analog Devices, Inc.
DSP Division
Three Technology Way
Norwood, MA 02062

Date Created:	06/06/03

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This directory contains an example on how to interface the ADSP-BF533 EZ-kit to an AD9244 Evaluation Board 
via the Extender Card.


Files contained in this directory (all source code in C language):

AD9244_ADC.dpj			VisualDSP++ project file
main.c				main routine 
InitPPI.c			initialization of PPI port and DMA channel
Init Interrupts.c		initialization and definition of Interrupts and service routine
Init SDRAM.c			initialize SDRAM controller
InitFlash.c			setup flash I/O port
readme.txt			this readme file
system.h			header file

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CONTENTS

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


I.    FUNCTIONAL DESCRIPTION

	Reads in continous streams of data from the ADC. The data is read into a memory buffer via the PPI interface of the ADSP-BF533.


II.   IMPLEMENTATION DESCRIPTION

 	A double buffering scheme is implemented so that data in one half of the input buffer is available for processing while the other
	half is being filled with new data via DMA operations. A flag indicates which half is ready for processing. In this example, the 
	main loop just copies the data that is ready into another buffer (only for demonstration purposes, you may display [plot menu]
	the data in VisualDSP from this buffer)
						

III.  OPERATION DESCRIPTION

	- follow the "hardware setup" instructions in the main comment header in "main.c"
	- Open the project "AD9244_ADC.dpj" in the VisualDSP Integrated Development Environment (IDDE).
	- Under the "Project" tab, select "Build Project" (program is then loaded automatically into DSP).
	- Feed an analog signal into the ADC (see AD9244 documentation)
	- Select "Run" from the "Debug" tab on the menu bar of VisualDSP.
	- Hit the stop button to halt the processor
	- Open a plot window: View->Debug Windows->Plot->New".  Display the "ADC_data" buffer by using the following configurations:
	  Address: browse for the variable ADC_data,  Count: 1024,  Format: short,
	  All of the other parameters can remain the same as default.  
	  Click "Add" after typing in the above configurations.  Then click ok.
	- You should see a portion of the analog signal that was fed into the ADC.
	- If you observe output flag PF2 on an oscilloscope, you will see the execution time of the "data processing" portion of main.
	  You must make sure that this time remains smaller than the interrupt period of the DMA blocks, if you modify this part of the code.
	- The main header file "system.h" contains #define statements to change buffer size and other options.