Traffic Controller in C using an HCS12 MCU

[chrismorr22]

SO I need a little push to get me started with the RTI and the for statement in this code:

// this program is a simple traffic light CONTROLLER program
// green on 4 seconds, yellow for 1 second, red for 5 seconds
// HCS12 controller,,,outputs on PORTA
// uses a RTI from timing control
// i will hook 5 output wires from each of the 6 bits on PORTA CONTROLLER 
//  TO LEDS




#include <hidef.h>            /* common defines and macros */
#include "derivative.h"       /* derivative-specific definitions */


//structure definition, type definition
struct state{
              unsigned  char  Out;
              unsigned  short Time;
              struct state *Next;                        // pointer to the struture for the next state
};
typedef state_type;   


#define S0  &fsm[0]
#define S1  &fsm[1]
#define S2  &fsm[2]
#define S3  &fsm[3]

state_type fsm[4] = {                                 // Traf Lite sequence - a structure containing 4 structures
    {0x21,400,S1},  
    {0x22,100,S2},  
    {0x0C,400,S3},
    {0x14,100,S0}
};     


void delay(int);  


static int counter = 0;


void main(void) 
{
    state_type *ptr;                            // setup a pointer to a state-type data structure...
    ptr = S0;                                     // ...and initialize it to point to state S0 in fsm
    PORTA = 0xFF;                          // initialize PORTA
     DDRA = 0xFF;
     CPMURTI = 0x01;                      // set RTI clock divide get 1mS interval
     CPMUFLG_RTIF = 1;                  // clear RTIF before enable INT
     CPMUINT_RTIE = 1;                  // enable RTI
     EnableInterrupts;                       // global enable


   for (;;)
   {
                                                 // ?????????CALL FUNCTIONS TO INITILIZE HARDWARE HERE 
   }
}


/******* Interrupt Service Routine ********/
#pragma CODE_SEG NON_BANKED 
interrupt ( ( (0x10000 - 0xFFF0) / 2 ) - 1 )  void isrRTI(void)
{


                          //???????????


  CPMUFLG_RTIF = 1;                             // clear RTIF
}


#pragma CODE_SEG DEFAULT  





void delay(int k )
{
   unsigned int i,j; 

   for (i=0;i<=k;i++)
   { /* adjust condition field for delay time */
     for (j=0;j<=0xff;j++)
     {
      asm("nop");
    }     
   }

[Satya]

For the first one you should initialize the hardware above the for loop and above enable interrupts, since it should be called only once. Regarding the second what is the question? You can leave the interrupt function as it is. You are clearing the rti interrupt flag that should be OK.