微處理器 - Microchip ATtiny13 - Assembly - Watchdog

參考資訊：
https://www.microchip.com/en-us/product/attiny13#Documentation
https://nerdathome.blogspot.com/2008/04/avr-as-usage-tutorial.html

本練習使用Watchdog Interrupt模式(不會執行Reset)，因此，Watchdog觸發後，會從Sleep指令繼續往下執行


main.s

    .equ PINB,  0x16
    .equ DDRB,  0x17
    .equ PORTB, 0x18
    .equ WDTCR, 0x21
    .equ MCUSR, 0x34
    .equ MCUCR, 0x35

    .equ LED,   1

    .org 0x0000
    rjmp main
    reti
    reti
    reti
    reti
    reti
    reti
    reti
    reti
    reti

    .org 0x0020
main:
    sbi DDRB, LED
    sbi PORTB, LED
    ldi r16, 0x30
    out MCUCR, r16
    ldi r16, 0x60
    out WDTCR, r16
    sei
    sleep
    cbi PORTB, 1
 
loop:
    rjmp loop

編譯和燒錄

$ avr-as -mmcu=attiny13 -o main.o main.s
$ avr-ld -o main.elf main.o
$ avr-objcopy --output-target=ihex main.elf main.ihex
$ sudo avrdude -c usbasp -p t13 -B 1024 -U flash:w:main.ihex:i

完成