Here is the task and below is the Reference Design CCS project code.

Task: Make a Duplicate of the Reference Design CCS project and start modifying the duplicate.

Create $$MyFilter$$ menu item in CCS project and implement the filter you designed $=>$ flash to the board.

Your filter should run in the DSP and be accessible through buttons S$1$ and S$2.$Place your filter first in the reference design menu system.

Test the design using the board and eg $3\mathrm{.}5$mm Y$-$cable $($mic $+$ speaker separated$)$

Input noisy signalOutput clear signal and test it with using the eg Android app called Spectroid.$$

Deliverables: two files $($can be zipped together$)$

$$

Report on the Texas Instruments DSP project implementation with Screenshots $($min $2$ pages, Screenshot from a Spectroid application from where we can see, that the noise "spike" has gone$)$

CCS code for implementing the filter

Code:

#include

#include "application.h$"$

$//$ Define buffer size

#define BUFFER$\_$SIZE $256$

$//$ Define pushbutton configurations

#define PUSHBUTTON$1\_$PORT P$1$

#define PUSHBUTTON$1\_$PIN BIT$1$

#define PUSHBUTTON$1\_$IFG P$1$IFG

#define PUSHBUTTON$2\_$PORT P$2$

#define PUSHBUTTON$2\_$PIN BIT$2$

#define PUSHBUTTON$2\_$IFG P$2$IFG

$//$ Global variables

bool enableFilter $=$ false; $//$ Filter control flag

float audioBuffer$[$BUFFER$\_$SIZE$]$; $//$ Audio buffer for processing

float filterHistory$[1]=\{0\}$; $//$ History for low$-$pass filter

$//$ Function prototypes

void initClock$($void$)$;

void initGpio$($void$)$;

void RunMyFilter$($void$)$;

$//$ Low$-$pass filter implementation

float lowPassFilter$($float input, float $*$history$)\{$

const float a$0=0\mathrm{.}8,$ a$1=0\mathrm{.}2$; $//$ Coefficients

float output $=$ a$0*$ input $+$ a$1*$ history$[0]$;

history$[0]=$ input; $//$ Update history

return output;

$\}$

$//$ Run "MyFilter" function

void RunMyFilter$($void$)\{$

for $($int i $=0$; i $<$ BUFFER$\_$SIZE; i$++)\{$

if $($enableFilter$)\{$

audioBuffer$[$i$]=$ lowPassFilter$($audioBuffer$[$i$],$ filterHistory$)$;

$\}$

$\}$

$\}$

$//$ Main function

int main$($void$)\{$

WDTCTL $=$ WDTPW $|$ WDTHOLD; $//$ Stop watchdog timer

initClock$()$;

initGpio$()$;

PM$5$CTL$0$ &$=$ ~LOCKLPM$5$; $//$ Clear lock bit

while $(1)\{$

RunMyFilter$()$; $//$ Process audio

$\}$

return $0$;

$\}$

$//$ Initialize clock

void initClock$($void$)\{$

PJSEL$0|=$ BIT$4|$ BIT$5$; $//$ XT$1$

CSCTL$0\_$H $=$ CSKEY $>>8$; $//$ Unlock CS registers

CSCTL$1=$ DCOFSEL$\_6$; $//$ Set DCO to $8$MHz

CSCTL$2=$ SELA$\_\_$LFXTCLK $|$ SELS$\_\_$DCOCLK $|$ SELM$\_\_$DCOCLK;

CSCTL$3=$ DIVA$\_\_1|$ DIVS$\_\_1|$ DIVM$\_\_1$; $//$ Set dividers

CSCTL$4$ &$=$ ~LFXTOFF;

do $\{$

CSCTL$5$ &$=$ ~LFXTOFFG; $//$ Clear fault flags

SFRIFG$1$ &$=$ ~OFIFG;

$\}$ while $($SFRIFG$1$ & OFIFG$)$; $//$ Wait for stabilization

CSCTL$0\_$H $=0$; $//$ Lock CS registers

$\}$

$//$ Initialize GPIO

void initGpio$($void$)\{$

P$1$OUT $=0$x$00$;

P$1$DIR $=0$xFF;

P$2$OUT $=0$x$00$;

P$2$DIR $=0$xFF;

$//$ Configure pushbuttons

GPIO$\_$setAsInputPinWithPullUpResistor$($PUSHBUTTON$1\_$PORT, PUSHBUTTON$1\_$PIN$)$;

GPIO$\_$selectInterruptEdge$($PUSHBUTTON$1\_$PORT, PUSHBUTTON$1\_$PIN, GPIO$\_$HIGH$\_$TO$\_$LOW$\_$TRANSITION$)$;

GPIO$\_$setAsInputPinWithPullUpResistor$($PUSHBUTTON$2\_$PORT, PUSHBUTTON$2\_$PIN$)$;

GPIO$\_$selectInterruptEdge$($PUSHBUTTON$2\_$PORT, PUSHBUTTON$2\_$PIN, GPIO$\_$HIGH$\_$TO$\_$LOW$\_$TRANSITION$)$;

$\}$

$//$ Interrupt handlers for buttons

void PORT$1\_$IRQHandler$($void$)\{$

if $($PUSHBUTTON$1\_$IFG & PUSHBUTTON$1\_$PIN$)\{//$ Button S$1$ pressed

enableFilter $=$ true; $//$ Enable filter

GPIO$\_$clearInterrupt$($PUSHBUTTON$1\_$PORT, PUSHBUTTON$1\_$PIN$)$;

$\}$

if $($PUSHBUTTON$2\_$IFG & PUSHBUTTON$2\_$PIN$)\{//$ Button S$2$ pressed

enableFilter $=$ false; $//$ Disable filter

GPIO$\_$clearInterrupt$($PUSHBUTTON$2\_$PORT, PUSHBUTTON$2\_$PIN$)$;

$\}$

$\}$