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collapseos/tests/avra/blink_tn45.asm

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; REGISTER USAGE
;
; R1: overflow counter
; R16: tmp stuff
.inc "avr.h"
.inc "tn254585.h"
.inc "tn45.h"
main:
ldi r16, RAMEND&0xff
out SPL, r16
ldi r16, RAMEND}8
out SPH, r16
sbi DDRB, 0
cbi PORTB, 0
; To have a blinking delay that's visible, we have to prescale a lot.
; The maximum prescaler is 1024, which makes our TCNT0 increase
; 976 times per second, which means that it overflows 4 times per
; second.
in r16, TCCR0B
ori r16, 0x05 ; CS00 + CS02 = 1024 prescaler
out TCCR0B, r16
2019-12-16 08:43:32 +11:00
clr r1
loop:
in r16, TIFR ; TIFR0
sbrc r16, 1 ; is TOV0 flag clear?
rcall toggle
rjmp loop
toggle:
ldi r16, 0b00000010 ; TOV0
out TIFR, R16
inc r1
cbi PORTB, 0
sbrs r1, 1 ; if LED is on
sbi PORTB, 0
ret