initial commit

1 files changed, 110 insertions, 0 deletions

diff --git a/timer.s b/timer.s
new file mode 100644
index 0000000..94e97ae
--- /dev/null
+++ b/timer.s
@@ -0,0 +1,110 @@
+.equ PINB,	0x03
+.equ DDRB,	0x04
+.equ PORTB,	0x05
+.equ PIND,	0x09
+.equ DDRD,	0x0A
+.equ PORTD,	0x0B
+.equ TIFR0,	0x15
+.equ ADDR,	0x256
+.equ SPL,	0x3D
+.equ SPH,	0x3E
+.equ SREG,	0x3F
+.equ TCCR0A,	0x0024
+.equ TCCR0B,	0x0025
+.equ TCNT0,	0x0026
+.equ OCR0A,	0x0027
+.equ TIMSK0,	0x006E
+.equ STOFL,	0xFF
+.equ STOFH,	0x08
+.equ TOIE0,	1
+
+.equ LOC,	0x128
+.equ FREQ,	0x80
+
+.org 0x0000 ; reset interrupt
+jmp init
+.org 0x0040 ; timer 0 overflow interrupt
+jmp tmrint
+
+
+.org 0x0068
+init:
+	; IO
+	sbi DDRB, 5
+	sbi DDRD, 2
+	cbi PORTB, 5
+	cbi PORTD, 2
+	; stack
+	ldi r16, STOFL
+	ldi r17, STOFH
+	out SPL, r16
+	out SPH, r17
+	; initial
+	ldi r16, 69
+	sts ADDR, r16
+	; timer
+	ldi r18, 0b00000001
+	out TCCR0B, r18
+	ldi r18, TOIE0
+	sts TIMSK0, r18
+	sei
+	rcall main
+
+tmrint:
+	push r18
+	in r18, SREG
+	push r18
+	push r19
+	push r20
+	push r21
+	
+	lds r20, LOC
+	ldi r21, FREQ
+	inc r20
+	cpse r20, r21
+	rjmp .stt
+
+	in r18, PORTD
+	ldi r19, (1 << 2)
+	eor r18, r19
+	out PORTD, r18
+	eor r20, r20
+.stt:
+	sts LOC, r20
+.exit:
+	pop r21
+	pop r20
+	pop r19
+	pop r18
+	out SREG, r18
+	pop r18
+	sei
+	reti
+
+
+main:
+	sei
+	ldi r17, 128
+.loop:
+	lds r1, ADDR
+	in r6,TCNT0
+	cp r1, r17
+	breq .finloop
+	inc r1
+	sts ADDR, r1
+	rjmp .loop
+.finloop:
+
+	in r13, PINB
+	in r14, PORTB
+
+	lds r16, ADDR
+	cpse r16, r17
+	cbi PORTB, 5
+
+	in r13, PINB
+	in r14, PORTB
+
+	rjmp main
+
+