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
.