;Sounding the Buzzer on PT0 using Chann 0 Timer (Output Compare option) of the Project Board
;PT0 of PORTT is connected to buzzer/speaker on Project Board using HCS12 MCU Module
;Notice this is NOT using any Time Delay
;Modified from Example 9-11 HCS12 book by Mazidi & Causey for Project BoardDragon and CodeWarrior 
  
;On Student Project Board, PT0 of PORTT is connected to buzzer/speaker permanently. It is accessed by BZ jumper. 
;MAKE SURE jumper for BZ (buzzer) is set. BZ JUMPER is part of group of jumpers called UFEA right next to the Buzzer itself 

;In Codewarrior, Make sure you are in TBDML Mode before downloading 
;Press F7 (to Make), then F5(Debug) to downLOAD,and F5 once more to start the program execution

 
        ABSENTRY Entry        ; for absolute assembly: mark this as application entry point
    
; Include derivative-specific definitions 
		INCLUDE 'mc9s12dp256.inc'     ;
 
 
;code section
        ORG   $4000     ;Flash ROM address for code
Entry:
	      LDS     #$4000    ;Stack
        BSET    DDRT,%00000001     ;Make PT0 an out for Buzzer 
          
;---Sound the Buzzer by toggling PT0 pin using Timer chan 0   
 			  ;Timer Chan0 set-up
	      LDAA 	#$80			 ;if you use $90, then NO need for "BSET	TFLG1,%00100000" 
	      STAA	TSCR1			 ;at the end of this program righ above BRA OVER
	      LDAA 	#$04    ;Prescaler=16. Change (0-7) to hear different sound
	      STAA	TSCR2			
	      BSET	TIOS,%00000001  ;Output Compare option for Channel 0	
	      LDAA 	#%00000001      ;Toggle PT0 pin option			
	      STAA	TCTL2
	      			
OVER	  LDD	  TCNT			
	      ADDD	#5000			       ;Change this number to hear different sound
	      STD	  TC0            			
HERE	  BRCLR	TFLG1,mTFLG1_C0F,HERE	
	      BSET	TFLG1,%00000001  ;Clear the Chan 0 Timer flag for next round (writing HIGH will clear it). No need for this if you use TSCR1=$90	
	      BRA   OVER
 
            
;**************************************************************
;*                 Interrupt Vectors                          *
;**************************************************************
            ORG   $FFFE
            DC.W  Entry     ;Reset Vector. CPU wakes here and it is sent to start of the code at $4000