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This commit is contained in:
Erick
2025-12-26 22:07:17 +01:00
parent b1b14bcdfa
commit e74d9369e1
2 changed files with 26 additions and 19 deletions
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src/led.inc
+7 -4
View File
@@ -1,8 +1,11 @@
; Registers:
; r16: timer0 start and stop operations
start_blink:
ldi r16, (1 << OCF0A) ; Clear timer status flag
ldi r16, (1 << OCF0A) ; Write Output Compare Flag 0 A to 1
out TIFR, r16 ; Clear Timer0 interrupt flag register
clr r16 ; Clear register
clr r16 ; Cleanup register
out TCNT0, r16 ; Reset Counter to 0
ldi r16, (1 << CS02) | (1 << CS00) ; Load prescaler value (00000101 = prescaler 1024)
@@ -16,9 +19,9 @@ stop_blink:
cbi PORTB, PB0 ; Set LED off
clr r16 ; Cleanup register
out TCCR0B, r16 ; Stop timer0 by clearing prescaler
out TCCR0B, r16 ; Stop timer0 by clearing prescaler
ldi r16, (1 << OCF0A)
out TIFR, r16 ; Clear Timer0 interrupt flag register
out TIFR, r16 ; Clear timer0 interrupt flag register
reti
src/timer.inc
+19 -15
View File
@@ -1,28 +1,32 @@
; Timer0 is static and used for the led
; Registers:
; r16: timer0 setup (can reuse after ret)
; r17: timer1 dynamic setup (always needed)
; Timer0 (static, low precision)
timer0_set:
ldi r16, (1 << WGM01) ; Load 00000010 to register (bit 1=CTC)
out TCCR0A, r16 ; On T/C Control Register A, enable CTC and
ldi r16, (1 << WGM01) ; Write CTC (Clear Timer on Compare) to 1
out TCCR0A, r16 ; On T/C Control Register A enable CTC waveform
ldi r16, 244 ; Load counter target limit value (ticks)
out OCR0A, r16 ; Compare target to current counter
out OCR0A, r16 ; Load target for compatison with TCNT0
ldi r16, (1 << OCIE0A) ; Output Compare Match A Interrupt Enable
out TIMSK, r16 ; Allow Timer0 to interrupt (mask register)
ldi r16, (1 << OCIE0A) ; Write Compare Match A Interrupt Enable to 1
out TIMSK, r16 ; Allow Timer0 to interrupt
ret
; Timer1 will be dynamically changed in main (tempo)
timer1_set:
;timer1_set:
; Load 10011011 to register:
; CTC1 (Bit 7): Reset timer to 0 when it matches OCR1C
; COM1A0 (Bit 4): Toggle OC1A (PB1) when it matches OCR1A
; CS13, CS11, CS10 (Bits 3,1,0): Prescaler 1024 (1011)
ldi r16, (1 << CTC1) | (1 << COM1A0) | (1 << CS13) | (1 << CS11) | (1 << CS10)
out TCCR1, r16 ; On T/C Control Register 1, enable: CTC1 COM1A0 CS13 CS11 CS10
; ldi r17, (1 << CTC1) | (1 << COM1A0) | (1 << CS13) | (1 << CS11) | (1 << CS10)
; out TCCR1, r16 ; On T/C Control Register 1, enable: CTC1 COM1A0 CS13 CS11 CS10
timer1_use:
ldi r16, 256 ; Load counter total value (ticks)
ldi r16, 5 ; Load counter on value (ticks)
; //TODO: change r16 on main and then call timer1_dyn to use the value already on r16 (so its dynamic)
out OCR1C, r16 ; Compare target to current counter (frequency)
out OCR1A, r16 ; Compare target to current counter (phase shift)
;timer1_use:
; ldi r17, 256 ; Load counter total value (ticks)
; ldi r17, 5 ; Load counter on value (ticks)
; //TODO: change r17 on main and then call timer1_dyn to use the value already on r16 (so its dynamic)
; out OCR1C, r17 ; Compare target to current counter (frequency)
; out OCR1A, r17 ; Compare target to current counter (phase shift)