Atmel AVR AT90S8515-4 Manuale Utente Scaricare il pdf (Pagina 10)

AN INTRODUCTION INTENDED FOR PEOPLE WITH NO PRIOR AVR KNOWLEDGE - AVRFREAKS.NET

Writing your First AVR Program

At this point you should have installed the software, and started up the a new

project called "Leds" You should also have the AT90S8515 Datasheet, stored

somewhere you can easily find it. If you can answer "Yes" to both these

questions, you are ready to continue writing some AVR Code.

In the Editor view in AVR Studio, continue your program (which at this point only

consists of the first line below) by adding the text below. (Cheaters can simply

cut & paste the source below into AVR Studio...)

Samplecode.asm

(file included in

files-folder)

;My Very First AVR Project

.include "8515def.inc" ;Includes the 8515 definitions file

.def Temp = R16 ;Gives "Defines" Register R16 the name

Temp

.org 0x0000 ;Places the following code from address

0x0000

rjmp RESET ;Take a Relative Jump to the RESET Label

RESET: ;Reset Label

ldi Temp, 0xFF ;Store 255 in R16 (Since we have defined

R16 = Temp)

out DDRB, Temp ;Store this value in The PORTB Data

direction Register

Loop: ;Loop Label

out PORTB, Temp ;Write all highs (255 decimal) to PORTB

dec Temp ;Decrement R16 (Temp)

rjmp Loop ;Take a relative jump to the Loop label

Note that the source code changes color when written in the editor window. This

is known as syntax highlighting and is very useful make the code more readable.

Once the Source code is entered, press CTRL + F7 or select [Build and Run] from

the [Project] Menu.

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Atmel AVR AT90S8515-4 Manuale Utente Pagina 10