;Toggling PORTB in Assembly Language for Dragon 12 Plus Trainer Board 
;with DeBug-12 monitor Program installed


#include "C:\Reg9s12.H"
;----------------------USE $1000-$1FFF FOR SCRATCH PAD 
R1      EQU     $1001
R2      EQU     $1002
R3      EQU     $1003

        ORG     $2000		;PROGRAM CODE ADDRESS 
        LDS     #$2FFF		;STACK	
        LDAA    #$FF
        STAA    DDRB		;MAKE PORTB AN OUTPUT PORT	
	BSET    DDRJ,%00000010	;MAKE PORTJ1 AN OUTPUT PIN	
	BCLR    PTJ,%00000010	;TURN OFF PORTJ1 TO ALLOW LEDs ON PORTB TO SHOW DATA 
;
;-------Toggling LEDs connected to PORTB

	LDAA #$55
BACK	STAA PORTB
	JSR DELAY
	COMA
	BRA BACK    

	



;----------DELAY
DELAY

        PSHA			;SAVE REG. A ON STACK
        LDAA    #24
        STAA    R3
L3      LDAA    #200
        STAA    R2
L2      LDAA    #250
        STAA    R1
L1      NOP
        NOP
        NOP
        DEC     R1
        BNE     L1
        DEC     R2
        BNE     L2
        DEC     R3
        BNE     L3
        PULA			;RESTORE REG A
        RTS
;-------------------
        END