;**************************************************************
;* This stationery serves as the framework for a              *
;* user application. For a more comprehensive program that    *
;* demonstrates the more advanced functionality of this       *
;* processor, please see the demonstration applications       *
;* located in the examples subdirectory of the                *
;* Freescale CodeWarrior for the HC12 Program directory       *
;**************************************************************
; Include derivative-specific definitions
            INCLUDE 'derivative.inc'

; export symbols
	XDEF	Entry,KVS,PRESSED,PRESSED_VAL,PORT_U,SEQUENCE,TON,TOFF,PORT_T,COUNTER
	XREF	__SEG_END_SSTACK,Keypad,PulseWidthMod

Variables:		Section
PRESSED     ds.b    1           ;the keypad value in the LUT
PRESSED_VAL ds.b    1           ;the numeral of the pressed key or the index of PRESSED in the LUT
TON         ds.b    1           
TOFF        ds.b    1
COUNTER     ds.b    1           ;"define a byte variable to use as a counter" ^1

Constants:	     Section
DDR_T       equ     $242        ;DC motor DDR
PORT_T      equ     $240        ;DC motor
DDR_U	      equ		  $26A
PSR_U       equ     $26D
PDR_U       equ     $26C
PORT_U      equ     $268        ;keypad
                  ;key value pairs from 4.3
KVS         dc.b  $EB,$77,$7B,$7D,$B7,$BB,$BD,$D7,$DB,$DD,$E7,$ED,$7E,$BE,$DE,$EE
                  ;given sequence from lab instructions (with trailing zero)
SEQUENCE    dc.b  $70,$B0,$D0,$E0,$00  
;=================================================================================
Code:			Section
Entry:      
            LDS     #__SEG_END_SSTACK
            
            BCLR    COUNTER,#$FF;initialize the counter to zero
            
            BSET    DDR_U,#$F0  ;bits 1-3 in bits 4-7 out
            BSET    PSR_U,#$F0  ;pins 1-3 pull up
            BSET    PDR_U,#$0F  ;pull up pins 1-3
            
            MOVB    #$80,CRGINT ;enable real-time interrupts
            MOVB    #$3C,RTICTL ;set RTI interval to 1 ms
            
            
            CLI                 ;enable interrupts

Main:
            JSR     Keypad      ;"The *unaltered* keypad routine from Lab 5.2 should be called in the main program."