//Variables

//We create variables for the time width values of each PWM input signal

unsigned long counter_1, counter_2, current_count;

//We create variables to stopre the previous value of the input signal (if LOW or HIGH)

byte last_CH1_state, last_CH2_state;

//To store the 1000us to 2000us value we create variables and store each channel

int input_CH1, input_CH2;      //In this example channel 1 of the receiver at pin D8 of the Arduino

/////////////////////////////////////////////////////////////////////////////////////

//Edit here if you have different signal from yout radio reciver

int min_value = 1000;             //min PWM value from receiver in us, usually 1000us

int max_value = 2000;             //max PWM value from receiver in us, usually 2000us

/////////////////////////////////////////////////////////////////////////////////////

//Inputs/outputs

int motor_CW = 6;

int motor_CCW = 9;

void setup() {

  PCICR |= (1 << PCIE0);    //enable PCMSK0 scan 

  PCMSK0 |= (1 << PCINT0);  //Set pin D8 trigger an interrupt on state change for CH1.                                               

  PCMSK0 |= (1 << PCINT2);  //Set pin D10 trigger an interrupt on state change.

  pinMode(motor_CW,OUTPUT);

  pinMode(motor_CCW,OUTPUT)

}

void loop() {

  int PWM_motor_CW = map(input_CH1, min_value, max_value, 0, 255);

  int PWM_motor_CCW = map(input_CH2, min_value, max_value, 0, 255);

  //Rotate CCW

  if(PWM_motor_CW > 5 && PWM_motor_CCW < 5)

  {

    analogWrite(motor_CW, LOW);

    analogWrite(motor_CCW, PWM_motor_CCW);

  }

  //Rotate CW

  if(PWM_motor_CW < 5 && PWM_motor_CCW > 5)

  {

    analogWrite(motor_CW, PWM_motor_CW);

    analogWrite(motor_CCW, LOW);

  }

  

  //if both are LOW, we stop both dirrections

  if(PWM_motor_CW < 5 && PWM_motor_CCW < 5)

  {

    analogWrite(motor_CW, LOW);

    analogWrite(motor_CCW, LOW);

  }

  //if both are HIGH, we stop both dirrections in order to not make short circuit

  if(PWM_motor_CW > 5 && PWM_motor_CCW > 5)

  {

    analogWrite(motor_CW, LOW);

    analogWrite(motor_CCW, LOW);

  }  

}

//This is the interruption routine

//----------------------------------------------

ISR(PCINT0_vect){

//First we take the current count value in micro seconds using the micros() function  

  current_count = micros();

  ///////////////////////////////////////             //Channel 1

  if(PINB & B00000001)                                //We make an AND with the pin state register, We verify if pin 8 is HIGH???

  {                               

    if(last_CH1_state == 0)                           //If the last state was 0, then we have a state change...

    {                                                 

      last_CH1_state = 1;                             //Store the current state into the last state for the next loop

      counter_1 = current_count;                      //Set counter_1 to current value.

    }

  }

  else if(last_CH1_state == 1)

  {                                                   //If pin 8 is LOW and the last state was HIGH then we have a state change      

    last_CH1_state = 0;                               //Store the current state into the last state for the next loop

    input_CH1 = current_count - counter_1;            //We make the time difference. Channel 1 is current_time - timer_1.

  }

  ///////////////////////////////////////Channel 2

  if(PINB & B00000100 )

  {                              //pin D10 - B00000100                                         

    if(last_CH2_state == 0)

    {                                             

      last_CH2_state = 1;                                                  

      counter_2 = current_count;                                               

    }

  }

  else if(last_CH2_state == 1)

  {                                             

    last_CH2_state = 0;                                                    

    input_CH2 = current_count - counter_2;                   

  }

}