// filename  COP12.C  
// add this file so that handle COP  
// COP reset could have been disabled by writing COPCTL=0;
// In this module however, COP is active
// Consequently, this module will create a TOF thread
//   to keep the active COP from generating a COP reset
// Last modified 8/17/00 by Jonathan W. Valvano
 
// Copyright 2000 by Jonathan W. Valvano, valvano@uts.cc.utexas.edu 
//    You may use, edit, run or distribute this file 
//    as long as the above copyright notice remains 


//******** TOFhandler ***************
// called when TCNT rolls over from $FFFF to 0
// at 500ns counting, interrupts every 32ms
#pragma interrupt_handler TOFhandler
void TOFhandler(void){
   TFLG2=0x80;           // TOF interrupt acknowledge
   PORTT^=0x40;          // toggle bit 6
   COPRST=0x55;          // make COP happy 
   COPRST=0xAA;
}
#pragma abs_address:0xffde
void (*TOF_vector[])() = { TOFhandler };
#pragma end_abs_address

//******** COPinit ***************
// Initialize TOF interrupts, enable timer,
// make PT6 an output, and enable interrupts 
void COPinit(void){
  DDRT |=0x40;  // PortT bit 6 is output
  TSCR =0x80;   // TCNT enable, TEN=1
  TMSK2=0xA2;   // TOI arm, TPU(pullup) timer/4 (500ns)
  CLKCTL=0x00;
asm(" cli"); // background TOF thread to keep COP happy
}