微處理器 - Microchip ATtiny13 - Assembly - Timer

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

本範例使用Prescaler 1024，當Timer Overflow時，觸發中斷，在中斷裡面Toggle LED


main.s

    .equ DDRB,   0x17
    .equ PORTB,  0x18
    .equ TIMSK0, 0x39 
    .equ TCNT0,  0x32
    .equ TCCR0B, 0x33

    .equ LED,    1

    .org 0x0000
    rjmp main
    reti
    reti
    rjmp timer_handler

    .org 0x0020
main:
    sbi DDRB, LED
    sbi PORTB, LED
    ldi r16, 0x00
    out TCNT0, r16
    ldi r16, 0x02
    out TIMSK0, r16
    ldi r16, 0x05
    out TCCR0B, r16
    ldi r16, 0x01
    ldi r17, 0
    sei
 
loop:
    rjmp loop

timer_handler:
    sbrs r17, 0
    cbi PORTB, LED
    sbrc r17, 0
    sbi PORTB, LED
    eor r17, r16
    reti

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