Controller 3

#include "TimerOne.h"
const int NUMBER_OF_FIELDS = 4;
int fieldIndex = 0;
long int values[NUMBER_OF_FIELDS];
volatile char LEDSwitch_Row;
volatile char LEDSwitch_Column;
volatile unsigned long int period = 8000;
volatile unsigned long int pulse_time = 400;
int ledPins[] = {0, 12, 11, 2, 9, 4, 5, 6, 13, 3, 10, 7, 8};
void setup() {
  timer_initialize();
  Serial.begin(19200);
  for(int thisPin = 2; thisPin < 14; thisPin++){
    pinMode(thisPin, OUTPUT);
  } 
}
void timer_initialize(){
  for(int i=1; i<8; i++){
    digitalWrite(ledPins[i], LOW);
  }
  for(int i=8; i<13; i++){
    digitalWrite(ledPins[i], HIGH);
  } 
  Timer1.initialize(period);
  Timer1.attachInterrupt(timer_ISR);
  Serial.println("Timer initialized.");
}
void timer_ISR(){
  LED(LEDSwitch_Row, LEDSwitch_Column);
  delayMicroseconds(pulse_time);
  digitalWrite(ledPins[LEDSwitch_Row], LOW);
  digitalWrite(ledPins[LEDSwitch_Column+7], HIGH);
}
void LED(char LEDSwitch_Row, char LEDSwitch_Column){
  digitalWrite(ledPins[LEDSwitch_Row], HIGH);
  digitalWrite(ledPins[LEDSwitch_Column+7], LOW);
}
void loop(){
  while(Serial.available()){
    char ch = Serial.read();
    if(ch >= '0' && ch <= '9'){
      if(fieldIndex < NUMBER_OF_FIELDS){
        values[fieldIndex] = (values[fieldIndex]*10) + (ch - '0');
      }
    }
    
    else if(ch == ','){
      fieldIndex++;
    }
    else{
      if(1 <= values[0] <= 7 && 1 <=values[1] <= 5){
        LEDSwitch_Row = values[0];
        LEDSwitch_Column = values[1];
        period = values[2];
        pulse_time = values[3];
        Serial.print("Row ");
        Serial.print(values[0]);
        Serial.print(", Column ");
        Serial.println(values[1]);
        Serial.print("Period: ");
        Serial.print(values[2]);
        Serial.println(" microseconds");
        Serial.print("Pulse Duration: ");
        Serial.print(values[3]);
        Serial.println(" microseconds");
        for(int i=0; i < min(NUMBER_OF_FIELDS, fieldIndex+1); i++){
          values[i] = 0;
        }
        fieldIndex = 0;
        timer_initialize();
      }  
      else{
        Serial.print("LED Position specified invalid. Please try again.");
      }     
    }  
  }
}