//Testing HCS12 MCU Module (from Freescale or Axiom) by Toggling PORTB in C Language 
 
//HCS12 MCU Modules can be used with Freescale Student Project Board and they are made by Axiom. 
//They can also be used as stand-alone without the project Board. This C code tests the MCU Module without the Project Board
//The HCs12 MCU Modules are either C128 (HCSxxx128), DT256 (HCSxxx256), or XDT512 (HCSxxx512). See the designation on your Module.
//These HCS12 MCU Module comes with BDM and ready to work with CodeWarrior(only). Connect the module to the x86 PC USB port via a USB cable.
//The MCU module has 4-bit green LEDs and are located between Brown POT and  Blue DIP SW. 
//The LEDs are connected to PORTB7-PORTB4 via row of jumpers right in front of LEDs.
//Make sure the Jumpers are set for LEDs. They are designateed as LED1-LED4  
//Make sure the VB jumper for Power_SEL (next to power jack) is ALSO set. VB is the middle Jumper and allows the power come from USB cable (500 mA Maximum)
//WHEN USB CABLE IS THE EXCLEUSIVE PROVIDER OF POWER TO CPU MODULE, NEVER USE IT TO DRIVE POWER HUNGRY DEVICES SUCH AS DC OR STEPPER MOTORS

//Modified from an example from Chapter 7 of HCS12 textbook by Mazidi & Causey
//Written and tested by Mazidi 
    
 
//In CodeWarrior, make sure you are in TBDML Mode before downloading 
//Press F7 (to Make), then F5(Debug) to downLOAD,and F5 once more to start the program execution
   

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


void MSDelay(unsigned int);
void main(void) 
{
  /* put your own code here */
  
    

    DDRB = 0xF0;    //PORTB7-POTB4 as output since LEDs are connected to it, Make sure to set the jumpers for it
  
    for(;;) 			
      {
        PORTB = 0x50;    //Toggle upper 4-bit of PORTB
        MSDelay(500);    //1/2 sec delay
        PORTB = 0xA0;
        MSDelay(500);
      }
 
}

//millisecond delay for XTAL=4MHz
//Axiom HCS12 MCU module uses 4 MHz XTAL for HCS12 .


 void MSDelay(unsigned int itime)
  {
    unsigned int i; unsigned int j;
    for(i=0;i<itime;i++)
      for(j=0;j<325;j++);    //1 msec. tested using Scope
  }