// filename  Tester.C  
// Jonathan W. Valvano, 12/16/02
// Digital filter tester
// PortS SCI Port0 serial I/O 
// COP reset will be disabled by COPCTL=0;
 
// Copyright 2003 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 "SCI12.H"
//******************PUT YOUR FILTER HERE***********************
#define fs 240
unsigned char x[6]; // this MACQ needs twice
unsigned char y[6];
unsigned int n=3;   // 3, 4, or 5
unsigned char Filter(unsigned char data){
  n++;
  if(n==6) n=3;     
  x[n] = x[n-3] = data;  // two copies of new data
  y[n] = (25*(x[n]+x[n-2])-18*y[n-2]+16)/32;
  y[n-3] = y[n];  // two copies
  return y[n];
} 
//*************************************************************

const unsigned char SinTab[100]={ // input dX= 200
128,122,115,109,103,97,91,85,
80,74,69,64,60,55,51,47,44,40,38,35,33,31,30,29,28,28,28,29,30,31,
33,35,38,40,44,47,51,55,60,64,69,74,80,85,91,97,103,109,115,122,
128,134,141,147,153,159,165,171,176,182,187,192,196,201,205,209,
212,216,218,221,223,225,226,227,228,
228,228,227,226,225,223,221,218,216,212,209,205,201,196,192,187,
182,176,171,165,159,153,147,141,134
};
//*****************CRLF***************
// Output a CR,LF to go to a new line
void CRLF(void){
  SCI_OutChar(CR);
  SCI_OutChar(LF);
}
// t=count/fs (seconds)
// v(t)=128+200*sin(2*pi*f*t)
// i=100*(2*pi*f*t)/(2*pi)=(100*f*count)/fs
// i=i%100
// x = SinTab[i]
unsigned short count; // integer time
unsigned short i;     // index into SinTab
unsigned short f;     // frequency of test wave
unsigned char in,out;
void RunFilter(void){
  i = (100*f*(long)count)/fs;
  i = i%100;  // to to 99
  in = SinTab[i];  
  out = Filter(in);     // call your filter
}
void Test(void){ 
unsigned short MinY,MaxY;
unsigned short Gain;  // dY/dX in percent
unsigned short dY;    // output amplitude
  MaxY = 0;
  MinY = 255;
  for(count = 0; count < 500; count++){ // initialize filter
    RunFilter(); 
  }
  for(count = 500; count < 1000; count++){ // run filter
    RunFilter(); 
    if(out>MaxY) MaxY=out;
    if(out<MinY) MinY=out;
  }
  dY = MaxY-MinY;  // amplitude of filter output
  if(f == 0){
    Gain = (100*MaxY)/128;
  }
  else{
    Gain = dY/2;     // 0 to 100, decimal fixed point 0.01
  } 
  SCI_OutString("f = "); SCI_OutUDec(f);
  SCI_OutString(" Hz    Gain = "); 
  SCI_OutUDec(Gain/100); SCI_OutChar('.');
  SCI_OutUDec((Gain%100)/10);  // tenths digit
  SCI_OutUDec(Gain%10);        // hundredths digit
  CRLF();
}  

void main(void){  unsigned short freq;
  COPCTL=0x00;    // disable COP 
  SCI_Init(13);
  
  SCI_OutString("Digital filter tester 12/16/02 -JWV"); CRLF();
  
  f = 0; Test();
  f = 10; Test();
  f = 20; Test();
  f = 30; Test();
  f = 40; Test();
  for(freq = 50; freq <= 70; freq++){
    f = freq; Test();
  }
  f = 80; Test();
  f = 90; Test();
  f = 100; Test();
}
#include "SCI12A.C"
// SCI12.C  uses gadfly synchronization
// SCI12a.C uses interrupt synchronization

extern void _start();	/* entry point in crt12.s */
#pragma abs_address:0xfffe
void (*reset_vectors[])() = { _start };
#pragma end_abs_address