readme.txt

这是DSP信号处理中关于led循环显示的测试程序。

ADSP-BF535 EZ-KIT Lite ASM_Timer Demo

Analog Devices, Inc.
DSP Division
Three Technology Way
P.O. Box 9106
Norwood, MA 02062


Date Created:	1/30/02

This directory contains example ADSP-BF535 code that demonstrates the use of
the Timer and general purpose I/O pins by blinking LEDs on the board.

Files contained in this directory:

readme.txt		this file
asm_timer.asm		assembly file for the timer blink routine 
asm_timer.dpj		VisualDSP++ project file
asm_timer.dxe		executable for this project
ADSP-BF535_asm.ldf	linker description file 
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CONTENTS

I.	FUNCTION/ALGORITHM DESCRIPTION
II.	IMPLEMENTATION DESCRIPTION
III.	OPERATION DESCRIPTION


I.  FUNCTION/ALGORITHM DESCRIPTION

The ASM_TIMER demo contains an implementation of a subroutine
that initializes general purpose I/O pins, core timer, and interrupts.  
Once the timer is initialized, the main code simply loops waiting for the timer to expire.  
Upon timer expiration, a core timer interrupt is generated and the handler 
toggles the state of the general purpose I/O pins.  The expected output is the alternate blinking 
of PF0/PF2 and PF1/PF3.  These pins are connected to LEDs on the ADSPBF535 EZ-KIT Lite for viewing.


II.  IMPLEMENTATION DESCRIPTION

The ADSP-BF535 is loaded with the ASM_TIMER program.
The main modules perform the following:

1. The GP I/O's are set to outputs.
2. The core timer Period and Width registers are initialized.
3. The core timer interrupt is enabled.
4. Timer is enabled.
5. Main code loops, waiting for the core timer count to expire and generate an interrupt.


III.  OPERATION DESCRIPTION

- Open the project "asm_timer.dpj" in the VisualDSP Integrated Development and Debugger Environment (IDDE).
- Under the "Project" tab, select "Build Project".
- Open a ADSP-BF535 EZ-KIT Lite session in the Debugger.
- Load "asm_timer.DXE" 
- Place breakpoints as desired to see the operation of the program.
- Focus on the ADSP-BF535 and select "RUN" from the menu bar.
- View the LEDs on the EZ-KIT Lite to see the Timer in action.