/*******************************************************************
This sketch is based on an example from AdaFruit for the Trinket and adapted for the ATTiny 45
 
 *******************************************************************/

#include <Adafruit_SoftServo.h>  // SoftwareServo (works on non PWM pins)

#define SERVO1PIN 3   // Servo control line goes to (Arduino Pin A3/3) ATTiny45 Pin 2
#define POTPIN   1   // Potentiometer sweep (center) (Arduino Pin A1/2/SCK) ATTiny45 Pin7 

Adafruit_SoftServo myServo1  //create a servo object

  int potValue;  // variable to read potentiometer
  int servoPos;  // variable to convert voltage on pot to servo position
   
void setup() {
  // Set up the interrupt that will refresh the servo for us automagically
  OCR0A = 0xAF;            // any number is OK
  TIMSK |= _BV(OCIE0A);    // Turn on the compare interrupt (below!)
  
  myServo1.attach(SERVO1PIN);   // Attach the servo to (Arduino Pin A3/3) ATTiny45 Pin 2
  myServo1.write(90);           // Tell servo to go to position per quirk
  delay(15);                    // Wait 15ms for the servo to reach the position
}

void loop()  {

  potValue=analogRead(POTPIN);             // Read voltage on potentiometer
  servoPos = map(potValue, 0, 1023, 0, 179);  // scale it to use it with the servo (value between 0 and 180) 
  myServo1.write(servoPos);                   // tell servo to go to position

  delay(15);                              // waits 15ms for the servo to reach the position
}

// We'll take advantage of the built in millis() timer that goes off
// to keep track of time, and refresh the servo every 20 milliseconds
volatile uint8_t counter = 0;
SIGNAL(TIMER0_COMPA_vect) {
  // this gets called every 2 milliseconds
  counter += 2;
  // every 20 milliseconds, refresh the servos!
  if (counter >= 20) {
    counter = 0;
    myServo1.refresh();
    myServo2.refresh();
  }
}