interrupt_polling_sw1.asm

  XDEF Entry            ; export 'Entry' symbol
  ABSENTRY Entry        ; for absolute assembly: mark this as application entry point
          
  INCLUDE 'mc9s12c32.inc'
  
ROMStart    EQU  $4000
  ORG RAMStart
  
Lamp DC.B $01
Counter1  DC.W  $FFFF
Counter2  DC.W  $0010
Temp  DC.B  $00
  
  ORG ROMStart
  
Entry:
  LDS #RAMEnd+1
  ;ANDCC #$BF
  
  LDAA  #$00  ; PE0
  STAA  DDRE
  
  LDAA  #$01
  STAA  DDRA
  
  LDAA  #$10
  STAA  DDRB
  
  LDAA  #$10  ; ilk isigi yakar
  ;LDAA  Lamp
  STAA  PORTA ; LED1 ON
  STAA  PORTB ; LED2 OFF
  
LOOP:
  
  JSR poll
  JSR delayS
  BRA LOOP

delayS:
  LDY Counter2
delaySLoop: 
  JSR delayMs
  DEY
  BNE delaySLoop
  RTS
delayMs:
  LDX Counter1
delayMsLoop:
  DEX
  BNE delayMsLoop
  RTS
  
poll:
  LDAB  PORTE
  ANDB  #$01
  CMPB  #$01
  BEQ   Return
  LDAB  Temp
  CMPB  #$01
  BEQ   Return2
  COMA
  STAA  PORTA
  STAA  PORTB
  LDAB  #$01
  STAB  Temp
Return:
  LDAB  #$00
  STAB  Temp
Return2:
  RTS