// Chapter 15 6812 C programs
// Jonathan W. Valvano, 2/26/07
// This software accompanies the book,
// Embedded Microcomputer Systems: Real Time Interfacing, Second Edition
// published by Thomson Engineering, 2006


// 9S12C32 C implementation, interrupts at a frequency of fs
unsigned short x[2],y;   
// x[0] is x(n) current sample
// x[1] is x(n-1) previous sample  
void interrupt 13 TC5handler(void){
  TFLG1 = 0x20;      // ack OC5F
  TC5 = TC5+PERIOD;  // Executed every 1/fs
  x[1] = x[0];       // shift MACQ data
  x[0] = ADC_In(CHANNEL);  // new data
  y = (x[0]+x[1])>>1;
}
void DAS_Init(void){ // start sampling
  asm sei        // make atomic
  ADC_Init();    // Program 11.13
  TIOS |= 0x20;  // enable OC5
  TSCR1 = 0x80;  // enable, 4 MHz TCNT
  TIE |= 0x20;   // Arm output compare 5
  TFLG1 = 0x20;  // Initially clear C5F
  TC3 = TCNT+50; // First one right away
  x[0] = x[1] = 0;
  asm cli 
}
//Program 15.1. Real time data acquisition with a simple digital filter, Equation 2.




// 9S12C32 C implementation, interrupts at 360Hz
unsigned short n,x[12],y;   
// x[n]   is x(n) current sample
// x[n-1] is x(n-1) sample 1/360 sec ago
// x[n-2] is x(n-2) sample 2/360 sec ago
// x[n-3] is x(n-3) sample 3/360 sec ago
// x[n-4] is x(n-4) sample 4/360 sec ago
// x[n-5] is x(n-5) sample 5/360 sec ago
void interrupt 13 TC5handler(void){
  TFLG1 = 0x20;      // ack OC5F
  TC5 = TC5+11111;   // Executed at 360 Hz
  n++; if(n==12) n=6;     
  x[n] = x[n-6] = ADC_In(CHANNEL);  // new data
  y = (x[n]+x[n-1]+x[n-2]+x[n-3]+x[n-4]+x[n-5])/6;
}
void DAS_Init(void){ // start sampling
  asm sei        // make atomic
  ADC_Init();    // Program 11.13
  n = 6;         // rotates through 6,7,8,9,10,11
  TIOS |= 0x20;  // enable OC5
  TSCR1 = 0x80;  // enable, 4 MHz TCNT
  TIE |= 0x20;   // Arm output compare 5
  TFLG1 = 0x20;  // Initially clear C5F
  TC3 = TCNT+50; // First one right away
  asm cli 
}
//Program 15.2. Real time data acquisition with a simple digital filter, Equation 3.




// 9S12C32 C implementation, interrupts at 360Hz
unsigned char x[4],y;   // 8-bit ADC
// x[0] is x(n) current sample
// x[1] is x(n-1) sample 1/360 sec ago
// x[2] is x(n-2) sample 2/360 sec ago
// x[3] is x(n-3) sample 3/360 sec ago
void interrupt 13 TC5handler(void){
  TFLG1 = 0x20;      // ack OC5F
  TC5 = TC5+11111;   // Executed at 360 Hz
  x[3] = x[2];       // shift MACQ data
  x[2] = x[1];
  x[1] = x[0];   
  x[0] = ADC_In(CHANNEL);  // new 8-bit data
  y = (x[0]+x[3])>>1;
}
void DAS_Init(void){ // start sampling
  asm sei        // make atomic
  ADC_Init();    // Program 11.13
  TIOS |= 0x20;  // enable OC5
  TSCR1 = 0x80;  // enable, 4 MHz TCNT
  TIE |= 0x20;   // Arm output compare 5
  TFLG1 = 0x20;  // Initially clear C5F
  TC3 = TCNT+50; // First one right away
  asm cli 
}
//Program 15.3. Real time data acquisition with a simple digital filter, Equation 4.












// 9S12C32 C implementation, interrupts at a frequency of fs
unsigned short x,y[2];   
// y[0] is y(n) current filter output
// y[1] is y(n-1) filter output 1 sample ago
void interrupt 13 TC5handler(void){
  TFLG1 = 0x20;        // ack OC5F
  TC5 = TC5+PERIOD;    // Executed every 1/fs
  y[1] = y[0];         // shift MACQ data
  x = ADC_In(CHANNEL); // new data
  y[0] = (x+y[1])/2;
}
void DAS_Init(void){ // start sampling
  asm sei        // make atomic
  ADC_Init();    // Program 11.13
  TIOS |= 0x20;  // enable OC5
  TSCR1 = 0x80;  // enable, 4 MHz TCNT
  TIE |= 0x20;   // Arm output compare 5
  TFLG1 = 0x20;  // Initially clear C5F
  TC3 = TCNT+50; // First one right away
  asm cli 
}
//  Program 15.5. Real time data acquisition with a simple IIR digital filter, Equation 5.






																	
unsigned char Median(unsigned char u1,unsigned char u2,unsigned char u3){ 
unsigned char result;
  if(u1>u2)
    if(u2>u3)     result = u2;   // u1>u2,u2>u3       u1>u2>u3
      else
        if(u1>u3) result = u3;   // u1>u2,u3>u2,u1>u3 u1>u3>u2
        else      result = u1;   // u1>u2,u3>u2,u3>u1 u3>u1>u2
  else 
    if(u3>u2)     result = u2;   // u2>u1,u3>u2       u3>u2>u1
      else
        if(u1>u3) result = u1;   // u2>u1,u2>u3,u1>u3 u2>u1>u3
        else      result = u3;   // u2>u1,u2>u3,u3>u1 u2>u3>u1
  return(result);
}
unsigned char x[3],y;   
// x[0] is x(n) the current sample
// x[1] is x(n-1) the sample 1/fs ago
// x[2] is x(n-2) the sample 2/fs ago
void sample(void){
   x[2] = x[1];  // shift MACQ data
   x[1] = x[0];   
   x[0] = ADC_In(0);  // new data from channel 0
   y=median(x[0],x[1],x[2]); 
}
//Program 15.6: The median filter is an example of a nonlinear filter.


// 9S12C32 C implementation 
unsigned short x[3],y[3];   
// x[0] is x(n) current sample
// x[1] is x(n-1) 1 sample ago
// x[2] is x(n-2) 2 samples ago
// y[0] is y(n) current filter output
// y[1] is y(n-1) filter out 1 ago
// y[2] is y(n-2) filter out 2 ago
void interrupt 13 TC5handler(void){
  TFLG1 = 0x20;          // ack C5F
  TC5 = TC5+16667;       // 240Hz
  y[2]=y[1]; y[1]=y[0];  // shift MACQ
  x[2]=x[1]; x[1]=x[0];
  x[0] = ADC_In(CHANNEL); // new data
  y[0]=(113*(x[0]+x[2])-98*y[2])>>7;
} 
//   Program 15.7. Real time data acquisition with a 60 Hz notch digital filter, Equation 58.






//*****************old programs from first edition******************

#include "FILTER.H"   // prototype file for your filter
void Collect(void){ short data;
  data = ADC_In(0);   // sample
  Fifo_Put(data);
}
void main(void){ short x,y;      // filter input/output
  LCD_Init();
  Filter_Init(100,1000,&Collect); // notch at 100 Hz, sampling at 1000 Hz
  for(;;){
    while(Fifo_Get(&x)==0){}; // wait for input
    y = Filter(x);            // execute filter
    LCD_Display(y);           // show results 
  }
}
//Program 15.8. Example application of the real-time DAS and filter.


                       


//  Program 15.1. Real time data acquisition with a simple digital filter, Equation 2.
// MC68HC812A4
#define Rate 2000
#define OC5  0x20
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){
   TFLG1=OC5;       // ack OC5F
   TC5=TC5+Rate;    // Executed every 1 ms
   x[1]=x[0];       // shift MACQ data
   x[0] = A2D(channel);  // new data
   y=(x[0]+x[1])>>1;}

void ritual(void) { 
asm(" sei");     // make atomic
  TIOS|=OC5;     // enable OC5
  TSCR|=0x80;    // enable
  TMSK2=0x32;    // 500 ns clock
  TMSK1|=OC5;    // Arm output compare 5
  x[0] = x[1] = 0;
  TFLG1=OC5;     // Initially clear C5F
  TC5=TCNT+Rate; // First one in 1 ms
asm(" cli"); }

//  Program 15.2. Real time data acquisition with a simple digital filter, Equation 3.
// MC68HC812A4
#define OC5  0x20 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){ unsigned int i;
   TFLG1=OC5;       // ack OC5F
   TC5=TC5+5556;    // fs=360Hz
   for(i=5;i>0;i++) 
       x[i]=x[i-1];      // shift MACQ data
   x[0] = A2D(channel);  // new data
   y=(x[0]+x[1]+x[2]+x[3]+x[4]+x[5])/6;}
void ritual(void) { 
asm(" sei");     // make atomic
  TIOS|=OC5;     // enable OC5
  TSCR|=0x80;    // enable
  TMSK2=0x32;    // 500 ns clock
  TMSK1|=OC5;    // Arm output compare 5
  x[0]=x[1]=x[2]=x[3]=x[4]=x[5]=0;
  TFLG1=OC5;     // Initially clear C5F
  TC5=TCNT+5556; 
asm(" cli"); } 

//  Program 15.3. Real time data acquisition with a simple digital filter, Equation 4.
// MC68HC812A4
#define OC5  0x20 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){ 
   TFLG1=OC5;       // ack OC5F
   TC5=TC5+5556;    // fs=360Hz
   x[3]=x[2];       // shift MACQ data
   x[2]=x[1];
   x[1]=x[0];   
   x[0] = A2D(channel);  // new data
   y=(x[0]+x[3])>>1;}     
void ritual(void) { 
asm(" sei");     // make atomic
  TIOS|=OC5;     // enable OC5
  TSCR|=0x80;    // enable
  TMSK2=0x32;    // 500 ns clock
  TMSK1|=OC5;    // Arm output compare 5
  x[0]=x[1]=x[2]=x[3]=0;
  TFLG1=OC5;     // Initially clear C5F
  TC5=TCNT+5556; 
asm(" cli"); } 

 // Program 15.4. Compiler listings for the filter implementation.
; MC68HC812A4, ICC12
; y=(x[0]+x[3])>>1;
  ldab _x+3  ; 8-bit x[3]
  clra       ; promote into RegD
  std -10,x  ; save on stack
  ldab _x    ; 8 bit x[0]
  clra       ; promote into RegD
  addd -10,x ; 16-bit x[0]+x[3]
  asra
  rolb       ; 16-bit shift
  stab _y    ; demote to 8 bit  

//   Program 15.5. Real time data acquisition with a simple digital filter, Equation 5.
// MC68HC812A4
#define Rate 2000
#define OC5  0x20
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){
   TFLG1=OC5;       // ack OC5F
   TC5=TC5+Rate;    // Executed at fs
   y[1]=y[0];       // shift MACQ data
   x = A2D(channel);  // new data
   y[0]=(x+y[1])>>1;} // 16-bit

void ritual(void) { 
asm(" sei");     // make atomic
  TIOS|=OC5;     // enable OC5
  TSCR|=0x80;    // enable
  TMSK2=0x32;    // 500 ns clock
  TMSK1|=OC5;    // Arm output compare 5
  y[0] = y[1] = 0;
  TFLG1=OC5;     // Initially clear C5F
  TC5=TCNT+Rate; // First one in 1 ms
asm(" cli"); } 

// Program 15.6: The median filter is an example of a nonlinear filter.
unsigned char Median(unsigned char u1,unsigned char u2,unsigned char u3){ 
unsigned char result;
  if(u1>u2)
    if(u2>u3)   result=u2;     // u1>u2,u2>u3       u1>u2>u3
      else
        if(u1>u3) result=u3;   // u1>u2,u3>u2,u1>u3 u1>u3>u2
        else      result=u1;   // u1>u2,u3>u2,u3>u1 u3>u1>u2
  else 
    if(u3>u2)   result=u2;     // u2>u1,u3>u2       u3>u2>u1
      else
        if(u1>u3) result=u3;   // u2>u1,u2>u3,u1>u3 u2>u1>u3
        else      result=u1;   // u2>u1,u2>u3,u3>u1 u2>u3>u1
  return(result):}
unsigned char x[3],y;   
// x[0] is x(n) the current sample
// x[1] is x(n-1) the sample 1/fs ago
// x[2] is x(n-2) the sample 2/fs ago
void sample(void){
   x[2]=x[1];  // shift MACQ data
   x[1]=x[0];   
   x[0] = A2D(0);  // new data from channel 0
   y=median(x[0],x[1],x[2]); 

//    Program 15.7. Real time data acquisition with a 60 Hz notch digital filter, Equation 58.
// MC68HC812A4
#define OC5  0x20 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){ 
   TFLG1=OC5;       // ack OC5F
   TC5=TC5+8333;    // fs=240Hz
   y[2]=y[1]; y[1]=y[0];  // shift MACQ
   x[2]=x[1]; x[1]=x[0];   
   x[0] = A2D(channel);  // new data
   y[0]=(113*(x[0]+x[2])-98*y[2])>>7;}     

void ritual(void) { 
asm(" sei");     // make atomic
  TIOS|=OC5;     // enable OC5
  TSCR|=0x80;    // enable
  TMSK2=0x32;    // 500 ns clock
  TMSK1|=OC5;    // Arm output compare 5
  y[0]=y[1]=y[2]=x[0]=x[1]=x[2]=0;
  TFLG1=OC5;     // Initially clear C5F
  TC5=TCNT+8333; 
asm(" cli"); }