;Displaying Overflow Timer on LEDs of PORTB in Assembly for Dragon12+ Trainer with D-Bug12 installed
;for AsmIDe and MiniIDE. Many of the register's name used in AsmIDe and MiniIDe are different from the HCS12 Documentation
;Modified from Example 9-3 in HCS12 book by Mazidi & Causey
 
       
#include "C:\Reg9s12.H"
   
    ;code section
        ORG   $2000     
        LDS   #$2000    ;Stack
        LDAA    #$FF
        STAA    DDRB		;Make PORTB output
  ;PTJ1 controls the LEDs connected to PORTB (For Dragon12+ ONLY)
        LDAA    #$FF      	
        STAA    DDRJ   	;Make PORTJ output, (Needed by Dragon12+) 
        LDAA    #$0
        STAA    PTJ   	;Turn off PTJ1 to allow the LEDs on PORTB to show data (Needed by Dragon12+) 
;
;-------Toggling ALL LEDs connected to PORTB
   			
        LDAA 	#$80			
        STAA	TSCR	     ;TSCR1 				
        LDAA 	#$07	    ;Prescaler=16 (Try 0-7 values to see changes on LEDs) 
        STAA	tmsk2	    ;(TSCR2) notice the name is different in AsmIDE and MiniIDE assemblers 		
        LDAA	#0			
OVER	BSET	TFLG2,%10000000	      ;clear the Timer overflow flag (writing HIGH clears it)
H1	BRCLR	TFLG2,$80,H1   		;wait for Timer Overflow
	INCA				                ;keep adding the overflows
	STAA	PORTB                 ;and dump it on PORTB to see
	BRA	OVER