.include "tn15def.inc"

.def  temp  =R25
.def  itemp =R24
.def  itemp2=R23
.def  lock  =R1
.def  cnt0  =R2
.def  cnt10 =R19
.def  cnt11 =R20
.def  TOcnt0 =R22
.def  TOcnt1 =R18
.def  Status = R21

.equ  rot =0
.equ  gelb =1
.equ  gruen =3

		.cseg
    rjmp start  ;1 $000 RESET External Reset, Power-on Reset,Brown-out Reset, and Watchdog Reset
    rjmp IRQ0   ;2 $001 INT0 External Interrupt Request 0
    reti        ;3 $002 I/O Pins Pin Change Interrupt
    reti        ;4 $003 TIMER1, COMPA Timer/Counter1 Compare Match A
    rjmp Timer1 ;5 $004 TIMER1, OVF Timer/Counter1 Overflow
    rjmp Timer0 ;6 $005 TIMER0, OVF Timer/Counter0 Overflow
    reti        ;7 $006 EE_RDY EEPROM Ready
    reti        ;8 $007 ANA_COMP Analog Comparator
    reti        ;9 $008 ADC ADC Conversion Complete
		
		
start:
    ldi temp,$ff
    out PORTB,temp

    ldi temp,$05 ; // Timer0 Prescaler = CK/1024 (ca. 5.2 Hz bei Overflow)
    out TCCR0,temp

    ldi temp,$08  // Timer1 Prescaler = CK/8 
    out TCCR1,temp

    ldi temp,$40
    out GIMSK,temp;  // INT0 einschalten

    ldi temp,$06
    out TIMSK,temp  // erst nur Timer1 einschalten --> Ampelphasen einmal durchlaufen

    clr cnt0
    clr cnt10
    clr cnt11

    // Port B einrichten (die ersten 2+4 bits auf Ausgang)
    ldi temp,0b00001011
    out DDRB,temp

    // Zuerst Ampel auf rot stellen
    sbi PORTB,gelb
    sbi PORTB,gruen
    cbi PORTB,rot
    clr Status

    mov TOcnt0,Status
    mov TOcnt1,Status

    ldi temp,$30 // low level of int0, and enable sleep-mode as powerdown
    out MCUCR,temp

main_loop:
    sei
    nop
    nop
    cli
    cpi TOcnt1,$5
    brne  main_loop;
     //wenn die Phasen einmal durchlaufen wurden, dann Timer abschalten          
    ldi temp,$FF
    out PORTB,temp
    sei
    sleep


    clr TOcnt0;
    mov TOcnt1,TOcnt0
    out TIMSK,TOcnt0
    
		rjmp start


IRQ0:
    tst lock
    brne  exit_irq
    ser itemp
    mov lock,itemp        // merken, dass Taste gedrückt wurde ... /elektronisches entsperren;
                    // Timer 0 Interrupt einschalten
    
    clr itemp
    out TCNT1,itemp

    mov TOcnt0,itemp
    mov TOcnt1,itemp

    cpi Status,$2
    brne  to_grn
    
    ldi Status,$4
    reti

to_grn:
    clr Status

exit_irq:
    reti;



Timer1:
    clc
    ldi itemp,$1
    add cnt10,itemp
    brcc  t1_add
    inc cnt11
t1_add:
    cpi cnt11,$3
    brne  exit_t1
      
    inc Status
    cpi Status,$1
    brne  s2
    // Rot->Rot+Gelb
    cBi PORTB,gelb
    rjmp  exit_t1a
s2:
    cpi Status,$2
    brne  s3
    // Rot+Gelb --> Grün
    sBi PORTB,rot
    sBi PORTB,gelb
    cBi PORTB,gruen
    rjmp  exit_t1a
s3:
    cpi Status,$3
    breq  dec_unlock

    cpi Status,$5
    brne s6
    // Grün -->Gelb
    sBi PORTB,rot
    CBi PORTB,gelb
    SBi PORTB,gruen
    rjmp  exit_t1a
s6:
    cpi Status,$7
    brne  exit_t1a
    // Gelb -->Rot
    cbi PORTB,rot
    sBi PORTB,gelb

dec_unlock:
    dec Status
    clr lock


exit_t1a:
    clr cnt10
    clr cnt11
    
exit_t1:
    reti;

Timer0:
    dec TOcnt0
    brne  exit_t0

    ldi itemp2,$1
    add TOcnt1,itemp2

exit_t0:
    reti;