Hello, I had developed one application using STVD

[Siddharth Kachhia]

Posted on March 25, 2017 at 10:03

#include 'Filter.h'

#define Samples 3

#include <math.h>

#include <stdlib.h>

extern unsigned long int data;

long int Result_Previous,Average,;

unsigned char Stable;

void FIR_Filter(unsigned long int Clean)

{

    static unsigned char Index=0;

//    static bit_16 Index1=4000;

    static unsigned long int ADC_Mean[Samples];

    

    unsigned long int Absolute;

    unsigned char Count;

//    Average = Clean>>5;

    Clean >>= 5;

    ADC_Mean[Index] = Clean;

    Average = 0;

    {    

        for(Count=0;Count<Samples;Count++)

        {

            Average+=ADC_Mean[Count];

             }

        Average /= Samples;

    }

    if(Index >= (Samples-1))

        Index=0;

    else

        Index++;

    Absolute = abs(Average - Result_Previous);

    

   if(Absolute <5)

    {

        Average = Result_Previous +((Average - Result_Previous)>>2);

    }

    if(Absolute<3)

        Stable++;

    else

        Stable=0; 

    

    Result_Previous = Average;

//    return (Average);

        data = Average;

}

this is my code in interrupt function.. i think problem with this statement addition in variable not working in interrupt function  ' Average+=ADC_Mean[Count];'

how can addition in that variable??

Help me for this.. Thank you..

[S.Ma]

Posted on March 25, 2017 at 15:07

Unclear. Interrupt routine should be as short as possible = as little computation as possible.

What is the signal triggering the interrupt? Which frequency?

Try to do the minimum in the interrupt, pass the result in a dedicated global register and set a RAM flag (to prevent future interrupts to corrupt the data). The main loop will wait for the flag, grab the data, divide, and clear the flag.

[Siddharth Kachhia]

Posted on March 27, 2017 at 07:01

Signal triggering is a falling edge and frequency is 2MHz.

[Arlet Ottens]

Posted on March 25, 2017 at 15:25

If you're modifying global variables inside an interrupt handler, and you want to access them outside, you need to declare them as 'volatile'.