求助，谁会用28335来做FIR低通语音滤波

您好,這顆MCU本身就有帶FIR相關範例了,可參考

相關程式碼節錄

#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

#include "FPU.h"

#include "math.h"

#include "float.h"

 

/* Filter Symbolic Constants                        */

#define FIR_ORDER    63 /* ORDER = NUM_TAPS - 1 */     

#define SIGNAL_LENGTH (FIR_ORDER+1)* 4 

                                     

                                        

/* Create an Instance of FIRFILT_GEN module and place the object in "firfilt" section       */ 

#pragma DATA_SECTION(firFP, "firfilt")

//#pragma DATA_SECTION(firFP_c, "firfilt")

FIR_FP  firFP = FIR_FP_DEFAULTS;

                                            

/* Define the Delay buffer for the 50th order filterfilter and place it in "firldb" section */  

#pragma DATA_SECTION(dbuffer, "firldb")

float dbuffer[FIR_ORDER+1];

#pragma DATA_SECTION(sigIn, "sigIn");

#pragma DATA_SECTION(sigOut, "sigOut");  

float sigIn[SIGNAL_LENGTH];

float sigOut[SIGNAL_LENGTH];

         

/* Define Constant Co-efficient Array  and place the

.constant section in ROM memory                */

#pragma DATA_SECTION(coeff, "coefffilt");

float const coeff[FIR_ORDER+1]= FIR_FP_LPF64;

/*

 * Calculating a digital frequency

 * Let sampling frequency = 1MHz

 * primary signal @ 10KHz and a secondary signal @ 40KHz

 * Therefore k1 = 1K/100k = 0.01

 *           k2 = 33K/100k = 0.33

 * composite signal = 1/2(sin(2*pi*i*k1) + sin(2*pi*i*k2))

 *                  = 1/2(sin(0.062831853071 * i) + sin(2.073451151*i))

 */

float RadStep = 0.062831853071f;  

float   RadStep2 = 2.073451151f;

float Rad = 0.0f;

float  Rad2 = 0.0f;

/* Filter Input and Output Variables                */   

float xn,yn;

int count = 0;

void main()

{

 unsigned int i;

 //Initalize sys clocks and PIE table

 InitSysCtrl();

 DINT;

 InitPieCtrl();

 IER = 0x0000;

 IFR = 0x0000;

 InitPieVectTable();

 EINT;   // Enable Global interrupt INTM

 ERTM;   // Enable Global realtime interrupt DBGM   

 // Generate sample waveforms:

 Rad = 0.0f;

   

 for(i=0; i < SIGNAL_LENGTH; i++)

    {

 sigIn[i]=0;

        sigOut[i]=0;

    }   

 /* FIR Generic Filter Initialisation    */ 

 firFP.order=FIR_ORDER; 

 firFP.dbuffer_ptr=dbuffer;

 firFP.coeff_ptr=(float *)coeff; 

 firFP.init(&firFP);

    for(i=0; i < SIGNAL_LENGTH; i++)

   {

   xn=0.5*sin(Rad) + 0.5*sin(Rad2); //Q15

 sigIn[i]=xn;

        firFP.input= xn;

        firFP.calc(&firFP);

        yn = firFP.output;

        sigOut[i]=yn;

 Rad = Rad + RadStep;

 Rad2 = Rad2 + RadStep2;

    }

 while(1) 

 {

 }       

} /* End: main() */

以上供參考