#define  DA_Write PORTC.B0
float a0,a1,a2,b_1,b_2,M1,M2,rk,rk_1,rk_2,ek,sk;
long yk,uk;
void Inatialize_AD(){
ADCON1=0b00000001;   //ALL PORT A AS Analog AND refrance are AN3
ADCON0=0x41;        //Select AN0
}
void Inatialize_TMR0(){
/*OPTION_REG.B5=0; //TMR0 Clock Source Select bit
OPTION_REG.PSA=0; // Prescaler is assigned to the Timer0 module
OPTION_REG.PS0=1;
OPTION_REG.PS1=0;
OPTION_REG.PS2=1;  //Set pre-scaler to 64*/
OPTION_REG=0b00000101;
TMR0=100;
INTCON.GIE=1;
INTCON.T0IE=1;
INTCON.T0IF=0;
}
void Read_AD(){
   yk=(long)ADC_Read(0);
   yk=yk*5000;  // Convert to
   yk=yk/1023;  // MV  OR Convert from level to voltage
}
void interrupt(){
PORTD=~PORTD;
 TMR0=100;
 Read_AD();
 ek = sk - yk; /* Calculate error term */
 rk = ek + M1;
 yk = a0*rk + M2; /* Calculate output */
 uk = (yk*256)/5000; //Convert to Level again
 PORTB = uk; /* Send to PORT B */
 DA_Write = 0; /* Write to D/A converter */
 DA_Write = 1;
 rk_2 = rk_1; /* Update variables */
 rk_1 = rk;
 M1 = -b_1*rk_1 - b_2*rk_2;
 M2 = a1*rk_1 + a2*rk_2;
 INTCON.T0IF= 0; /* Re-enable timer interrupts */
}
void main() {
  TRISD=0;
  PORTD=0;
  INTCON.GIE=1;
  INTCON.T0IE=1;
  a0 = 1;      a1 = 0.8;      a2 = 1.2;
  b_1 = 1.85;   b_2 = 0.92;
  M1 = 0;       M2 = 0;        rk = 0;    rk_1 = 0;   rk_2 = 0;
  sk = 1.0;
  TRISA = 1; /* RA0 (AN0) is input */
  TRISB = 0; /* PORT B is output */
  TRISC = 0; /* RC0 is output */
  DA_Write = 1; /* Disable D/A converter */
  Inatialize_AD(); /* Initialize A/D converter */
  Inatialize_TMR0(); /* Initialize timer interrupts */
for(;;); /* Wait for an interrupt */
}