use setPrescale function

Author: Bolukan

Adafruit_PWMServoDriver.cpp

@@ -165,14 +165,7 @@ void Adafruit_PWMServoDriver::setPWMFreq(float freq) {
   Serial.println(prescale);
 #endif
 
-  uint8_t oldmode = read8(PCA9685_MODE1);
-  uint8_t newmode = (oldmode & ~MODE1_RESTART) | MODE1_SLEEP; // sleep
-  write8(PCA9685_MODE1, newmode);                             // go to sleep
-  write8(PCA9685_PRESCALE, prescale); // set the prescaler
-  write8(PCA9685_MODE1, oldmode);
-  delay(5);
-  // This sets the MODE1 register to turn on auto increment.
-  write8(PCA9685_MODE1, oldmode | MODE1_RESTART | MODE1_AI);
+  setPrescale(prescale);
 
 #ifdef ENABLE_DEBUG_OUTPUT
   Serial.print("Mode now 0x");