/* Mealy FSM   filename  MEALY11.C
   Simulator program of a Mealy Finite State Machine

   This example accompanies the book
     "Embedded Microcomputer Systems: Real Time Interfacing", Brooks-Cole, copyright (c) 2000,
      Jonathan W. Valvano 7/6/99

   Interface between the TExaS simulator running a MC68HC11 EVB
      with ICC11 freeware compiler 
   TExaS Copyright 1999 by Jonathan W. Valvano 
   for more information about ICC11 
      see http://www.imagecraft.com
   You may use this file without restrictions
*/

/* PortC bit 7 is input, bit 3 is output */

#include "HC11.h"

const struct State{
   unsigned int Time;            /* Time to wait in each state */
   unsigned char Out[2];         /* Output if input=0,1 */
   const struct State *Next[2];  /* Next state if input=0,1 */
};
typedef const struct State StateType;
typedef StateType * StatePtr;

#define SA &fsm[0]
#define SB &fsm[1]
#define SC &fsm[2]
#define SD &fsm[3]
StateType fsm[4]={
   {200,{0,0},{SB,SD}},
   {200,{0,8},{SC,SA}},
   {100,{0,0},{SB,SD}},
   {100,{8,8},{SC,SA}}
};

void Wait(unsigned int delay){ int Endt;
    Endt=TCNT+delay;        /* Time (500ns cycles) to wait */
    while((Endt-(int)TCNT)>0);   /* wait */
};

StatePtr Pt;  /* Current State */
unsigned char Input;
void main(void){   
  Pt=SA;           /* Initial State */
  DDRC=0x08;       /* PortC bit3 is output */
  while(1){
    Wait(Pt->Time);    /* Time to wait in this state */
    Input=PORTC>>7;    /* Input=0 or 1 */
    PORTC=Pt->Out[Input];
    Pt=Pt->Next[Input];
  }
};
void resetVectors(void){
/* not really a function, 
   but this must be last */
  asm(" org $FFFE");
  asm(" FDB __start");
  asm(" org $FC00"); /* puts rts in a harmless place */
/* string constants also placed here */
/* the value FC00 means you can have up to 1000 characters of strings  */
}