; Chapter 1 9S12C32 assembly language programs
; Jonathan W. Valvano, 2/07/07
; This software accompanies the book,
; Embedded Microcomputer Systems: Real Time Interfacing, Second Edition
; published by Thomson Engineering, 2006
;

; MC9S12C32
PTT  equ $0240
PTIT equ $0241
DDRT equ $0242
;Program 1.2. Assembly definitions of an I/O port.


; MC9S12C32
    ldaa  #$0F
    staa  DDRT
;Program 1.4. Assembly software that initializes pins 7-4 to input and pins 3-0 to output.





; MC9S12C32
     org   $4000 ;ROM
Main ldaa  #$0F  ;make PT3-0
     staa  DDRT  ;outputs
Controller
     ldaa  #5 
     staa  PTT   ;set 0101
     ldaa  #6 
     staa  PTT   ;set 0110
     ldaa  #10 
     staa  PTT   ;set 1010
     ldaa  #9 
     staa  PTT   ;set 1001
     bra   Controller
     org   $FFFE
     fdb   Main  ;Reset vector
;Program 1.6. Assembly software for the LED output system.