CMST / Mbed 2 deprecated ELEC347_Coursework

V001. 2017_11_30 10:21 Working code from Tuesday's lab session.

Dependencies:   mbed-rtos mbed

Fork of 2017_11_28_ELEC347_Coursework by Chris Hills

DSP Coursework ELEC347 2017-2018 Group members: Matthew Thewsey, Thomas Morris, Samuel Waggett, Christopher Hills .

Filter.cpp

Committer:
mwthewsey
Date:
2017-11-28
Revision:
1:b088b771a591
Parent:
0:d39a06ca6bf1
Child:
2:f6e49378dd8a

File content as of revision 1:b088b771a591:

#include "Filter.hpp"

FILTER::FILTER(int Fs, int Fo, int Boost, int Q) //Constuctor
{
    _Fs = Fs;
    this-> _Fo = Fo;
    this-> _Boost = Boost;
    this-> _Q = Q;

    // B - Upnominator coefficients
    _b0 = 0.0201;
    _b1 = 0.0;
    _b2 = -0.0402;
    _b3 = 0.0;
    _b4 = 0.0201;

    // A - Denominator coefficients
    _a0 = 1.0000;
    _a1 = -2.5494;
    _a2 = 3.2024;
    _a3 = -2.0359;
    _a4 = 0.6414;

    _centreTap = 1;
    _G = 0;
    _k = 0;
    _Wo = 0;

    _xn = 0;     //this value is the input value
    _xnm1 = 0;
    _xnm2 = 0;
    _xnm3 = 0;
    _xnm4 = 0;

    _yn = 0;
    _ynm1 = 0;
    _ynm2 = 0;
    _ynm3 = 0;
    _ynm4 = 0;
}

FILTER::~FILTER() {}

void FILTER::setvalue(int RAW_input)
{
            
    _xn = RAW_input;
    _centreTap = _xn*_b0 + _xnm1*_b1 + _xnm2*_b2 + _xnm3*_b3 + _xnm4*_b4;  //IIR Filter
    _yn = _centreTap*_a0 - _a1*_ynm1 - _a2*_ynm2  - _a3*_ynm3 - _a4*_ynm4; //Result in yn

    FilterOutput=_yn+0.5f;       //Output resultant to DAC. Again MBED uses 0.0 to 1.0 float!!!!!! and Offset to give 0 to 3V3 range

    //THESE NEED TO BE LOADED IN THIS ORDER OTHERWISE ALL xnm VALUES WILL BECOME THE SAME AS xn
    _xnm4 = _xnm3;
    _xnm3 = _xnm2;
    _xnm2 = _xnm1;
    _xnm1 = _xn;

    //THESE NEED TO BE LOADED IN THIS ORDER OTHERWISE ALL ynm VALUES WILL BECOME THE SAME AS yn
    _ynm4 = _ynm3;
    _ynm3 = _ynm2;
    _ynm2 = _ynm1;
    _ynm1 = _yn;

}

float FILTER::getvalue(void)
{
    return FilterOutput;  
}

https://os.mbed.com/users/thomasmorris/code/ELEC347_CourseWork/