chap15.c

摩托罗拉Mc6811利程

// Chapter 15 6811 C programs
// Jonathan W. Valvano
// This software accompanies the book,
// Embedded Microcomputer Systems: Real Time Interfacing
// published by Brooks Cole, 1999

//  Program 15.1. Real time data acquisition with a simple digital filter, Equation 2.
// MC68HC11A8
#define Rate 2000
#define OC5  0x08 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){
   TFLG1=OC5;      // Ack interrupt 
   TOC5=TOC5+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
   TMSK1|=OC5;  // Arm output compare 5
   x[0] = x[1] = 0;
   TFLG1=OC5;  // Initially clear OC5F
   TOC5=TCNT+Rate; // First one in 1 ms
asm(" cli"); }

//  Program 15.2. Real time data acquisition with a simple digital filter, Equation 3.
// MC68HC11A8
#define OC5  0x08 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){ unsigned int i;
   TFLG1=OC5;      // Ack interrupt 
   TOC5=TOC5+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
   TMSK1|=OC5;  // Arm output compare 5
   x[0]=x[1]=x[2]=x[3]=x[4]=x[5]=0;
   TFLG1=OC5;  // Initially clear OC5F
   TOC5=TCNT+5556; 
asm(" cli"); }

//  Program 15.3. Real time data acquisition with a simple digital filter, Equation 4.
// MC68HC11A8
#define OC5  0x08 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){ 
   TFLG1=OC5;      // Ack interrupt 
   TOC5=TOC5+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
   TMSK1|=OC5;  // Arm output compare 5
   x[0]=x[1]=x[2]=x[3]=0;
   TFLG1=OC5;  // Initially clear OC5F
   TOC5=TCNT+5556; 
asm(" cli"); }

 // Program 15.4. Compiler listings for the filter implementation.
; MC68HC11A8, ICC11
; y=(x[0]+x[3])>>1;
   ldy #1
   pshy
   ldab  _x+3  ; 8-bit x[3]
   clra        ; promote into RegD
   pshb        ; save on stack
   psha
   ldab  _x    ; 8 bit x[0]
   clra        ; promote into RegD
   tsy
   addd 0,y    ; 16-bit x[0]+x[3]
   puly
   puly
   jsr  __asrd ; 16-bit shift
   stab  _y    ; demote to 8 bit

//   Program 15.5. Real time data acquisition with a simple digital filter, Equation 5.
// MC68HC11A8
#define Rate 2000
#define OC5  0x08 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){
   TFLG1=OC5;      // Ack interrupt 
   TOC5=TOC5+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
   TMSK1|=OC5;  // Arm output compare 5
   y[0] = y[1] = 0;
   TFLG1=OC5;  // Initially clear OC5F
   TOC5=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.
// MC68HC11A8
#define OC5  0x08 
#pragma interrupt_handler TOC5handler()
void TOC5handler(void){ 
   TFLG1=OC5;      // Ack interrupt 
   TOC5=TOC5+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
   TMSK1|=OC5;  // Arm output compare 5
   y[0]=y[1]=y[2]=x[0]=x[1]=x[2]=0;
   TFLG1=OC5;  // Initially clear OC5F
   TOC5=TCNT+8333; 
asm(" cli"); }