File content as of revision 2:8b60d4eb7388:

#include "mbed.h"
#include <math.h>
#include <cmath>
#include "TSISensor.h"
#include "SLCD.h"
#define LEDON false
#define LEDOFF true
#define NUMBUTS 2   //two buttons
#define LBUT PTC12 //left button // port addresses for buttons
#define RBUT PTC3 //right button
#define ARGUMENTSTATE 0 //Switch case 0
#define ANSWERSTATE 1   //Switch case 1
#define LCDTIME 1.0 //LCD Timer 1 sec
#define TSILIMIT 0.01 
#define PRINTDELTA 0.01
#define LCDCHARLEN 10
#define DATAINTERVAL 0.1
#define BUTTONTIME 0.1
#define PROGNAME "KBrat-SSD541-Midterm-Q2a \nNewton's Method of Square Root\n\r"

SLCD slcd;//define LCD display globally define
Serial pc(USBTX, USBRX);

Timer LCDTimer; //for reading lcd input state for display
Timer dataTimer; //for reading data input states(from the slider 1-100)
Timer ButtonTimer; //for reading button states
DigitalIn buttons[NUMBUTS] = {RBUT, LBUT};
float tsidata;
int displayState = ARGUMENTSTATE;//Make initial state ARGUMENTSTATE

void initialize_global_vars(){
    pc.printf(PROGNAME);
    // set up DAQ timers
    ButtonTimer.start();
    ButtonTimer.reset();
    dataTimer.start();
    dataTimer.reset();
    LCDTimer.start();
    LCDTimer.reset();  
} 

void LCDMess(char *lMess){
        slcd.Home();
        slcd.clear();
        slcd.printf(lMess);
}

int main(void) {
    int i;
    char lcdData[LCDCHARLEN];
    float lastTouch = 0.0; //intial lastTouch starts at 0.0
    TSISensor tsi;
    float tempTSI;
    PwmOut gled(LED_GREEN);
    PwmOut rled(LED_RED);
    
    initialize_global_vars();

     while (true) {
        if (ButtonTimer > BUTTONTIME){
            for (i=0; i<NUMBUTS; i++){ // index will be 0 or 1 //find buttons
                if(!buttons[i]) { 
                    displayState = i;  
                } // if ! buttons
            }// for loop to look at buttons
            ButtonTimer.reset();
        }
        
        
        if(LCDTimer.read() > LCDTIME){
            LCDTimer.reset();                               
            switch (displayState){//start switch case for displayState 
                
                case ARGUMENTSTATE: {// case #0
                    rled = 0.0;//red light on
                    gled = 1.0;//green light off
                    
                    if(dataTimer.read() > DATAINTERVAL){
                        dataTimer.reset();                               
                        tempTSI = tsi.readPercentage();        
                        if (tempTSI > TSILIMIT){
                            tsidata = tempTSI;
                            if (fabs(tsidata - lastTouch)> PRINTDELTA){
                                pc.printf("Position %2.0f\n\r", tsidata*100);//print to computer tsidata*100 to get a range from 1-100
                            }           
                        }
                        lastTouch = tsidata;
                    }
        
                    sprintf (lcdData,"%2.1f",tsidata*100); //print to lcd screen tsidata*100 to get a range from 1-100
                    LCDMess(lcdData); 
                    
                    break;
                }
                
                case ANSWERSTATE: {
                    
                    rled = 1.0;//red light off
                    gled = 0.0;//green light on
                    
                    /*-------With built in sqrt function-----*/
                    /*double slid_input, sq_root;
                    slid_input = tsidata*100;
                    if (slid_input > 0){
                        sq_root = sqrt(slid_input);
                        pc.printf ("Square root(%f) = %f\n", slid_input, sq_root);
                        sprintf (lcdData,"%2.2f", sq_root);
                        LCDMess(lcdData);
                    //return 0;
                    }*/
                    
                    /*-------Without built in sqrt function-----*/
                    double x1, slid_input, sq_root;
                    slid_input = tsidata*100;
                    if(slid_input > 0){
                        sq_root = log(slid_input);
                            do {
                                x1 = (sq_root - (((sq_root * sq_root) - slid_input)/(2* sq_root))); //Newton's Method
                                sq_root = x1;
    
                            } while ((x1 * x1) > slid_input);
                                pc.printf ("Newton's Method: Square root(%2.2f) = %2.2f\n", slid_input, sq_root);
                                sprintf (lcdData,"%2.2f", sq_root);
                                LCDMess(lcdData);
                                }
                    break;
                }// end switch case displayState
            }                 
            LCDMess(lcdData); 
        } // end LCD timer.read
            
    }// end while(true)
        
}