/********************************************************************************
The?programme?of?the?IIR?filter?（Butterworth?type?2?order）.
Using?INT2?to?get?the?input?signal.
Array?x?is?the?input?signal?from?A/D?the?length?is?256?32-bit?floating?point.
Array?y?the?filter?output?signal?the?length?is?256?32-bit?floating?point.
Array?a?and?b?are?the?coefficient?of?the?IIR?filter?the?length?is?3.?
*********************************************************************************/
#pragma?CODE_SECTION（vect“vect“）

#include?“stdio.h“
#include?“math.h“
#define?pi?3.1415927
#define?IMR???*（pmem+0x0000）??
#define?IFR???*（pmem+0x0001）??
#define?PMST??*（pmem+0x001D）??
#define?SWCR??*（pmem+0x002B）??
#define?SWWSR?*（pmem+0x0028）?
#define?AL????*（pmem+0x0008）?

#define?CLKMD??0x0058?/*?clock?mode?reg*/

#define?Len?256

double?fsnlpassnlstopnhpassnhstopa[3]b[3]x[Len]y[Len];

void?biir2lpdes（double?fs?double?nlpass?double?nlstop?double?a[]?double?b[]）;

unsigned?int??*pmem=0;
ioport	unsigned?char	port8002;
int?in_x[Len];
int?m?=?0;
int?intnum?=?0;
double?xmean=0;
int?n=0;
int?flag?=?0;
int?ijpk=0;
double?w2w1w0;

void?cpu_init（）
{
????*（unsigned?int*）CLKMD=0x0;?????????//switch?to?DIV?mode?clkout=?1/2?clkin
?????while（（（*（unsigned?int*）CLKMD）&01）!=0）;
???*（unsigned?int*）CLKMD=0x77ff;??????//switch?to?PLL?
	
	PMST=0x3FA0;
	SWWSR=0x7fff;
	SWCR=0x0000;
	IMR=0;
	IFR=IFR;
}?

interrupt?void?int1（）???
{
	in_x[m]?=?port8002;
	in_x[m]?&=?0x00FF;
	m++;
	intnum?=?m;
	
	if?（intnum?==?Len）
	{
		intnum?=?0;
		
		xmean?=?0.0;
		
		for?（i=0;?i		{
			xmean?=?in_x[i]?+?xmean;
		}		
		
		xmean?=?1.0*xmean/Len;
		
		for?（i=0;?i		{
			x[i]?=?1.0*（in_x[i]?-?xmean）;
		}
		
		for?（i=0;?i	??	{?
			??w2?=?x[i]-a[1]*w1-a[2]*w0;
??????	????y[i]?=?b[0]*w2+b[1]*w1+b[2]*w0;
??????		??w0?=?w1;
??????		??w1?=?w2;
??????	}
		
		m=0;
		flag?=?1;
	}
}

??void?biir2lpdes（double?fs?double?nlpass?double?nlstop?double?a[]?double?b[]）
??
??{
????int?iuv;
	double?wpompgsat;
????wp=nlpass*2*pi;
	omp=tan（wp/2.0）;
	gsa=omp*omp;
	for?（i=0;?i<=2;?i++）
	??{
		u=i%2;
		v=i-1;
		a[i]=gsa*pow（2u）-sqrt（2）*omp*v+pow（-2u）;
	??}
	
	for?（i=0;?i<=2;?i++）
	??{	u=i%2;
		b[i]=gsa*pow（2u）;
	??}
	t=a[0];
	for?（i=0;?i<=2;?i++）
	??{	a[i]=a[i]/t;
		b[i]=b[i]/t;
	??}
??}
?
void?set_int（）????
{
	asm（“?ssbx?intm“）;
	IMR=IMR|0x0004;??
	asm（“?rsbx?intm“）;??
}

void?main（void）
{
	w2=w1=w0=0.0;
	cpu_init（）;
	
??	fs?=?250000;
??	nlpass?=?0.08;
	nlstop?=?0.28;
	
	biir2lpdes（fsnlpassnlstopab）;

	set_int（）;

	for（;;）
	{
		if?（flag?==?1）
		{
		???flag?=?0;????/*?set?breakpoint?here?*/

		}
	}
}

void?vect（）
{
???asm（“?.ref?_c_int00“）;/*pseudoinstruction*/
???asm（“?.ref?_int1“）;

???asm（“?b?_c_int00“）;/*?reset?*/??
???asm（“?nop“）;
???asm（“?nop“）;
???asm（“?rete“）;????????
???asm（“?nop“）;
???asm（“?nop“）;
???asm（

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件????????529??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\cc_build_Debug.log

?????文件???????6592??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\Debug\Exp-IIR-AD.map

?????文件???????7801??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\Debug\Exp-IIR-AD.obj

?????文件??????12739??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\Debug\Exp-IIR-AD.out

?????文件????????363??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\Debug.lkf

?????文件????????363??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\Debug.lkv

?????文件???????1407??2005-07-18?08:39??exp03_cpu2\Exp-IIR-AD\Exp-IIR-AD.paf

?????文件????????933??2005-07-18?08:38??exp03_cpu2\Exp-IIR-AD\Exp-IIR-AD.pjt

?????文件???????5326??2005-07-18?08:37??exp03_cpu2\Exp-IIR-AD.c

?????文件????????401??2004-03-03?09:29??exp03_cpu2\Exp-IIR-AD.cmd

?????文件???????2744??2002-07-29?22:38??exp03_cpu2\math.h

?????文件???????8397??2002-01-25?10:42??exp03_cpu2\MMRegs.h

?????文件?????154882??1999-08-24?10:51??exp03_cpu2\RTS.LIB

?????文件????????114??2001-10-06?20:15??exp03_cpu2\TYPEDEF.H

?????目錄??????????0??2009-05-13?18:32??exp03_cpu2\Exp-IIR-AD\Debug

?????目錄??????????0??2009-05-13?18:32??exp03_cpu2\Exp-IIR-AD

?????目錄??????????0??2009-05-13?18:32??exp03_cpu2

-----------?---------??----------?-----??----

???????????????202591????????????????????17