#include <SPI.h>
#include <Wire.h>
#include <Servo.h>

const int CSN = D7;
const int SERVO_PIN = D0;

Servo bilda_servo;
const byte numChars = 32;
char receivedChars[numChars];   // an array to store the received data
boolean newData = false;
float dataNumber = 0;             // new for this version

void setup()
{
  pinMode(SERVO_PIN, OUTPUT);
  bilda_servo.attach(SERVO_PIN, 500, 2500);

	Serial.begin(19200);
}

void loop() {
    recvWithEndMarker();
    float val = showNewNumber();
    Serial.print("Rotation:");
    Serial.print(val);
    Serial.print(",");
    Serial.print("Lower:");
    Serial.print(0);
    Serial.print(",");
    Serial.print("Upper:");
    Serial.println(300);
    float pwm_width = map(val, 0, 300, 500, 2500);
    bilda_servo.writeMicroseconds(pwm_width);
    delay(10);
}

void recvWithEndMarker() {
    static byte ndx = 0;
    char endMarker = '\n';
    char rc;
    
    if (Serial.available() > 0) {
        rc = Serial.read();

        if (rc != endMarker) {
            receivedChars[ndx] = rc;
            ndx++;
            if (ndx >= numChars) {
                ndx = numChars - 1;
            }
        }
        else {
            receivedChars[ndx] = '\0'; // terminate the string
            ndx = 0;
            newData = true;
        }
    }
}

float showNewNumber() {
    if (newData == true) {
        dataNumber = 0;             // new for this version
        dataNumber = atof(receivedChars);   // new for this version
        Serial.print("This just in ... ");
        Serial.println(receivedChars);
        Serial.print("Data as Number ... ");    // new for this version
        Serial.println(dataNumber);     // new for this version
        newData = false;
    }
    return dataNumber;
}