//Sending "YES" to Hyperterminal (or Tera Terminal) via Serial Com0 (SCI0) on HCS12G128 Tower board (TWR-S12G128)
//On TWR-S12G128 Serial COM0 (SCI0) is IDC 2x5 male header located next to brown POT. 
//The TWR-S12G128 board comes with a DB9-to-IDC-2x5 femal cable for connecting it to the COM port of x86 PC
//When connecting female IDC 2x5 to Tower,make sure pin 1 on IDC Tower board is lined up with the red stripe of the IDC-2x5 cable 
//If the IDC-2x5 cable is connected right, then RED stripe will be on side of USB power cable

//If your x86 PC does not have Serial COM port (with DB-9 connector)then you need USB to Serial Converter
// The best one we have seen is (TRENDnet USB to RS-232 Serial Converter TU-S9) from Amazon
//http://www.amazon.com/TRENDnet-RS-232-Serial-Converter-TU-S9/dp/B0007T27H8/ref=pd_bxgy_e_img_y  

//Modified and tested by Mazidi from Example 10-9C in HCS12 textbook by Mazidi & Causey

//In Codewarrior, make sure you are in Open Source BDM
//In Codewarrior F7(make), F5(Debug) and F5 again to start running

//Bring up HyperTerminal in Windows XP (or Tera Term in Windows Vista and Windows 7)
//and you will see YES appears on x86 PC screen  

//The HCS12G128 Tower works at 6.25 MHz Bus Freq.

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


void SerTx0(unsigned char);

void main(void) 
{
   
    PER0AD = 0x80;					// enable PU on PAD15 to enable COM for the HCS12G128 chip
                            //Notice this is different from HCS12DP256/512
    SCI0BDH=0x00;     
    SCI0BDL=41;     //12.5 MHz/2=6.25MHz, 6.25MHz/16=390,625 Hz and 390,625/9600=41 
    SCI0CR1=0x00;
    SCI0CR2=0x0C;
    for(;;)
      {
        SerTx0('Y');
        SerTx0('E');
        SerTx0('S');
        SerTx0(' ');
        
      }

}
  
 
void SerTx0(unsigned char c)  //SCI0 (COM0 of HCS12 chip)
  {
    while((SCI0SR1 & 0x80)==0);  //make sure the last bit is gone
    SCI0DRL=c;		       //before giving it another byte	
  }