#include <Wire.h>
//Fab Academy 2018
//Networking and communications
// I2C, Master and 4 slaves
//Gerardo.Saz

//  ---- SLAVE ----
int slave = 3;         // Set slave number (1,2 or 3)
void setup() { 
  Wire.begin(slave);   // join i2c bus with address 
  Wire.onReceive(requestEvent); // register event              
  Serial.begin(115200);  // start serial for output
 
  pinMode(3,OUTPUT); //External Led
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(3,LOW);
}

void loop() {  
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(100);                        // wait for a 0.1 second  
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(100);                        // wait for a 0.1 second  
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(100);                        // wait for a 0.1 second  
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(100);                        // wait for a 0.1 second  
  Serial.println(String(slave) + ": blah, ");
 }

// This function is executed when the master calls this slave.
// current processes are interrupted to execute the order.
void requestEvent(int howMany) {
  Serial.println("Slave #"+ String(slave) +", ok");
  Wire.read();
  for(double i = -PI/2; i <= 3*PI/2; i=i+ PI/30){
    int cathetus = 127 +(127 * sin(i)) ;  
    analogWrite (3, cathetus);
    delay(2000);
  }
  digitalWrite (3, LOW);
}