// filename  DAS.C  

// test of ADC, MAX549interface

// Analog input connected to channel1

// DAC output from MAX549 channel A

// real-time sampling at 360 Hz

// Last modified 4/12/02 by Jonathan W. Valvano

 

// Copyright 2002 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 



#include "HC12.h"

#include "MAX549.H"

unsigned char MaxX,MaxX,MinY,MinY,X,Y;

unsigned short Count;

void GainInit(void){

  MaxX = MaxY = 0;

  MinX = MinY = 255;

  Count = 0;

}



void GainMeasure(unsigned char x, unsigned char y){

  if(x>MaxX){ 

    MaxX = x;

  }

  if(x<MinX){ 

    MinX = x;

  }

  if(y>MaxY){ 

    MaxY = y;

  }

  if(y<MinY){ 

    MinY = y;

  }

  Count++;          // change 360 to match your sampling rate

  if(Count==360){   // calculate once a second

    X  =MaxX-MinX;  // amplitude of filter input

    Y = MaxY-MinY;  // amplitude of filter output

    GainInit();     // setup for next time

  }

}



void ADC_Init(void){

  ATDCTL2 = 0x80;   // Activate ADC  

  ATDCTL3 = 0;      // no freeze

  ATDCTL4 = 1;      // sample time 2 E clocks, /4 clock

}



unsigned char ADC_Sample(unsigned char chan){

  ATDCTL5 = chan;    // Start ADC 

  while ((ATDSTAT & 0x01) == 0){};  // wait for CCF0

  return(ADR0H); 

}



#define C5 0x20 

#define rate 5556

#pragma interrupt_handler TOC5handler()

void TOC5handler(void){ unsigned char data;

  TFLG1 = C5;           // ack C5F

  TC5 = TC5+rate;       // fs=360Hz (change this to match your sampling rate)

  data = ADC_Sample(1);  // new data from ADC channel 1

// put digital filter here for procedure part 2

  GainMeasure(x[0],y[0]);

  MAX549_DOUTA(data);

}  

#pragma abs_address:0xffe4

void (*TC5_interrupt_vector[])() = { TOC5handler};

#pragma end_abs_address

   

void ClockOpen(void) { 

asm(" sei");       // make atomic

  TIOS |= C5;      // enable OC5

  TSCR |= 0x80;    // enable

  TMSK2 = 0x32;    // 500 ns clock

  TMSK1 |= OC5;    // Arm output compare 5

  TFLG1 = C5;      // Initially clear C5F

  TC5 = TCNT+rate; 

asm(" cli"); 

}

 

void main(void){   // MAX549A DAC interface, Input to 6812 ATD1

  COPCTL = 0x00;   // disable COP 

  MAX549_Open();   // software from a previous lab

  ADC_Init();      // turn on ADC

  GainInit();

  ClockOpen();     // start background thread

  while(1){};      // copy ADC to DAC in background

}



#include "MAX549.C"

extern void _start();	

#pragma abs_address:0xfffe

void (*reset_vector[])() = { _start };

#pragma end_abs_address