And Finally the Breathing LED is Here, :)

Jonathan Ive style, Old Macbook Pro sleep indicator LED.

Using interrupt, fast PWM on ATTiny13A.

.include "../tn13Adef.INC" 

.def a = r16

.def b = r17

.def c = r18

.def d = r19

.org $0000              ; startup vector

    rjmp onReset

.org $0006              ; compare match vector

    rjmp Tim0CompA

onReset:

    ldi a, 1

    out OCR0A,a

    ldi b, 1

    ldi c, 0

    ldi d, 255

    

    sbi DDRB,0          ; port B0 as output

    

    ldi a, 0b10000011   ; pwm mode 3

    out TCCR0A, a

    

    ldi a, 0b00000011   ; divider 01/no 10/8 11/64 100/256 101/1024

    out TCCR0B,a

    

    ldi a, 0b0000100    ; enable compare interupt

    out TIMSK0,a

    

    sei

main:

    rjmp main

    

Tim0CompA:

    in a, OCR0A

    rjmp incdec

        switch:

    out OCR0A,a

    reti

incdec:

    sbrs b,0

    rjmp deca

    inc a

        back:

    cp a,c

    breq oneB

    cp a,d

    breq zeroB

        bBack:

    rjmp switch

    

    

deca:

    dec a

    rjmp back

    

oneB:

    ldi b,1

    rjmp bBack

zeroB:

    ldi b,0

    rjmp bBack

.