MSP430 Launchpad Rev. 1.4 and EasyDriver and StepperMotor

Other Parts Discussed in Thread: MSP430G2553

Hello all,

I am new to the forum and to the MSP430. I have a MSP430 Launchpad Rev. 1.4 and have a couple of questions, regarding a project which I'm currently building. 

I try to build a spectrometer (from this instruction) using a photo transistor and a stepper motor from an old CD-drive. So I have an Easy Driver breakout board to do my dirty job. So I don't use a serial to usb breakout board for communication between my PC and the MSP430 instead I use the launchpad itself and my first question is which jumpers should I remove/change in order to be able to send serial commands to my MSP430 from my PC? Do I have to change the position of TXD and RXD horizontally (the board is Rev 1.4)?  

My second question is that regarding the instruction I have to attach the emitter of the photo-transistor to P1_3, but I've noticed that the MSP430 has a hardware push button named P1_3 do I have to constantly press this button in order to get data from my photoransistor, attached at P1_3?

And my third question is that regarding the instruction I can use the RST (S1) pin as a +3V out is this true and do I have to change the jumpers to be able to use the RST (S1) as a +3V output.

Here is my code. 

//I/O Below
const int StepperMotor = P2_4;
const int StepperDirection = P2_5;
const int Sensors[] = {P1_3}; // Add more sensors here!

//Constants for calibration below!

const double nm = 405; // Known Calibration source Frequency
const double x = 37.65; // Distance of point above the "Screen"
const double D = 50.00; // distance to the "Screen"
const double degreesperstep = 1; // Degrees per step for the stepper motor
const double microstepping = 8; // This allows for you to determine how often you want the Sample to be taken (inverse microstep)
const double mmPerRotation = 2.76; // This is the distance between the two teeth of the spindle which moves the sensor up and down
const double heightofTray = 38.00; // Under estimate this a bit
const double starty = 32.35; //32.35

/////////////////////////Fiddle with the below at your own risk!///////////////////////////////////////////
const double stepsperrotation = 360/degreesperstep;
const double microstepsuntilend = heightofTray/mmPerRotation * stepsperrotation * (microstepping);
const double d = (nm*1e-9)/sin(atan(x/D));
//const double d = 720e-9;//const double x = (nm*1e-9*d);
int wavelengthvIntensity[sizeof(Sensors)-1];
int datafile = 0;
double cnt = 0;
char buf[30];
double tempnm = 0;
double currenty = 0;
const double zero = starty-x;
char ksk = '0';

void setup() {                
  pinMode(PUSH2, INPUT_PULLUP);
  Serial.begin(9600);  // Hah, I forgot to add this in Special thanks to tommy_goh1997 for spotting the bug!
  pinMode(StepperMotor, OUTPUT);     
  pinMode(StepperDirection, OUTPUT);
  digitalWrite(StepperMotor, LOW);
  digitalWrite(StepperDirection, LOW); //When Restarted the stepper motor will lower the sensor to the lowest.
   for (int i=0;i<sizeof(wavelengthvIntensity);i++) {
     pinMode(Sensors[i], INPUT);
   }
   for (int i = 0; i < microstepsuntilend; i++) {
    digitalWrite(StepperMotor, HIGH);
    delayMicroseconds(250);          
    digitalWrite(StepperMotor, LOW); 
    delayMicroseconds(250);   
   }
   digitalWrite(StepperDirection, HIGH);
}
void loop() {
  if (ksk == '1') {
    ksk = 0;
    cnt = 0;
 while (cnt < microstepsuntilend) {
  for (int i=0;i<sizeof(wavelengthvIntensity)-1;i++) {
    wavelengthvIntensity[i] = analogRead(Sensors[i]);
    Serial.print(wavelengthvIntensity[i]);
    Serial.print(", ");
  }
  Serial.println(tempnm);
  digitalWrite(StepperMotor, HIGH);
  delayMicroseconds(1);          
  digitalWrite(StepperMotor, LOW); 
  delayMicroseconds(1);       
  cnt++;
  //Serial.println(currenty);
  currenty = zero+((cnt/microstepsuntilend)  * heightofTray);
  tempnm = d*sin(atan((x+currenty)/D))*(1e9);
  }
  digitalWrite(StepperDirection, LOW);
  for (int i = 0; i < microstepsuntilend; i++) {
    digitalWrite(StepperMotor, HIGH);
    delayMicroseconds(250);          
    digitalWrite(StepperMotor, LOW); 
    delayMicroseconds(250);   
   }
   digitalWrite(StepperDirection, HIGH);
  Serial.println("$");
  }
  ksk = Serial.read();
}

Regards,
Plamen

P.S. Please excuse my English. I am not a native speaker.