CUK CONVERTER

INPUT SOURCE -SOLAR PANEL (MAXIMUM OPEN LOOP VOLTAGE =20V)
OUTPUT LOAD– BATTERY OF 12V ,WITH CONSTANT VOLTAGE OF 14V 
CIRCUIT

PROGRAM
 //feed back by 10k and 1k
//adc value —0.75 for 8
//adc=2733/4.88 ==560
//to get adc value =v/.11
//8—-150
//7.5–139
//7–132
int p=115;
void setup()
{
setPwmFrequency(9, 1);
analogWrite(9,p);
Serial.begin(9600);
}
void loop()
{
int a=analogRead(2);
delay(1);
Serial.println(p);
if(a>340)
{
  p=p-1;
  if(p<0)p=0;
  analogWrite(9,p);
}
if (a<320 )//&& a>100
{
  p=p+1;
  if(p>220)p=p-1;
  analogWrite(9,p);
}
}
void setPwmFrequency(int pin, int divisor) {
  byte mode;
  if(pin == 5 || pin == 6 || pin == 9 || pin == 10) {
    switch(divisor) {
      case 1: mode = 0x01; break;
      case 8: mode = 0x02; break;
      case 64: mode = 0x03; break;
      case 256: mode = 0x04; break;
      case 1024: mode = 0x05; break;
      default: return;
    }
    if(pin == 5 || pin == 6) {
      TCCR0B = TCCR0B & 0b11111000 | mode;
    } else {
      TCCR1B = TCCR1B & 0b11111000 | mode;
    }
  } else if(pin == 3 || pin == 11) {
    switch(divisor) {
      case 1: mode = 0x01; break;
      case 8: mode = 0x02; break;
      case 32: mode = 0x03; break;
      case 64: mode = 0x04; break;
      case 128: mode = 0x05; break;
      case 256: mode = 0x06; break;
      case 1024: mode = 0x7; break;
      default: return;
    }
    TCCR2B = TCCR2B & 0b11111000 | mode;
  }
}
/**
 * Divides a given PWM pin frequency by a divisor.
 *
 * The resulting frequency is equal to the base frequency divided by
 * the given divisor:
 *   – Base frequencies:
 *      o The base frequency for pins 3, 9, 10, and 11 is 31250 Hz.
 *      o The base frequency for pins 5 and 6 is 62500 Hz.
 *   – Divisors:
 *      o The divisors available on pins 5, 6, 9 and 10 are: 1, 8, 64,
 *        256, and 1024.
 *      o The divisors available on pins 3 and 11 are: 1, 8, 32, 64,
 *        128, 256, and 1024.
 *
 * PWM frequencies are tied together in pairs of pins. If one in a
 * pair is changed, the other is also changed to match:
 *   – Pins 5 and 6 are paired on timer0
 *   – Pins 9 and 10 are paired on timer1
 *   – Pins 3 and 11 are paired on timer2
 *
 * Note that this function will have side effects on anything else
 * that uses timers:
 *   – Changes on pins 3, 5, 6, or 11 may cause the delay() and
 *     millis() functions to stop working. Other timing-related
 *     functions may also be affected.
 *   – Changes on pins 9 or 10 will cause the Servo library to function
 *     incorrectly.
 *
 * Thanks to macegr of the Arduino forums for his documentation of the
 * PWM frequency divisors. His post can be viewed at:
 *   http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1235060559/0#4
 *
 */