;**********************************************************************
;                                                                     *
;    Filename:	    farol.asm                                         *
;    Date:          Novembro 2004                                     *
;    File Version:                                                    *
;                                                                     *
;    Author:        Mario Luzeiro  - a25408 at alunos.det.ua.pt       *
;    Company:       Azeiteiro Team                                    *
;                   http://sweet.ua.pt/~a25408/                       * 
;                                                                     *
;    Notes:         Codigo para implementar um farol para o concurso  *
;                   MicroRato de acordo com as regras de 2004         *
;                   36.8Khz modulados a 600hz com duty cyle de 30%    *
;                                                                     *
;                                                                     *
;**********************************************************************


	list      p=16f628            ; list directive to define processor
	#include <p16f628.inc>        ; processor specific variable definitions
	
	__CONFIG _INTRC_OSC_NOCLKOUT & _CP_OFF & _WDT_OFF & _BODEN_ON & _PWRTE_ON & _MCLRE_OFF & _LVP_OFF

    CBLOCK 0x20             ; Declare variable addresses starting at 0x20 
     Loop1,Loop2 
    ENDC
        
;**********************************************************************
		ORG     0x000             ; processor reset vector
		goto    main              ; go to beginning of program
main
; 
; ----------- 
; INITIALIZE 
; ----------- 
;
		CLRF   PORTA           ; Initialize port A 
		CLRF   PORTB           ; Initialize port B 

        BSF    STATUS,RP0      ; RAM bank 1 

        CLRF   TRISA           ; All pins port A output 
        CLRF   TRISB           ; All pins port B output 

        BCF    STATUS,RP0      ; RAM bank 0

; 
; ------------------------ 
; FUNCTION OF PORT A PINS 
; ------------------------ 
; 
        MOVLW    7 
        MOVWF    CMCON         ; Comparators off, all pins digital I/O 
; 
; ---------- 
; MAIN LOOP 
; ---------- 
; 
LOOP
		MOVLW   13
        MOVWF   Loop1 

OSCL40khz
; on all
		MOVLW b'11111111' 
        MOVWF PORTA
        MOVWF PORTB
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP					;= 0.0000011 s
;off all
        MOVLW b'00000000'   ;+ 0.0000001
        MOVWF PORTA
        MOVWF PORTB
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP					;= 0.0000010 s
        DECFSZ  Loop1,F 	;+ 0.0000001
        GOTO    OSCL40khz	;+ 0.0000002


		MOVLW   64
        MOVWF   Loop2
wait1ms
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP
        NOP        
		DECFSZ  Loop2,F
        GOTO    wait1ms

		GOTO LOOP


		END                    ; directive 'end of program'