[ARM] ADC interrupts using LPC2138 controller

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//ADC using interrupts ARM 7 LPC2138
#include <LPC213X.H>
unsigned int result=0;
//void t0_init_isr(unsigned int msec);
void adc_isr_init(void);
void adc_schedule()__attribute__((interrupt("FIQ")));
void initLCD(void);
void enable(void);
void LCD_WriteChar(char c);
void LCD_WriteString(char * string);
void LCD_Cmd(unsigned int cmd);
void delay(unsigned int msec)
{
  unsigned int i,j;
  for(i=0;i<1275;i++)
  {
    for(j=0;j<msec;j++);
  }
}
//void t0_schedule()__attribute__((interrupt("FIQ")));
//#define analog (1<<27) // AD0.0 pin on p0.27
//#define switch (1<<0) //pin0.0 
//#define s1 (IOPIN0 & switch)
/*void t0_init_isr(unsigned int msec)
{
    T0MCR = 0x03;//interrupt and reset on MR0
    T0MR0 = 3000*msec; //
    T0IR = 0x01; //timer 0 MR0 interrut
    VICIntSelect |=(1<<4);//selecting timer 0 interrupt
    VICIntEnable |=(1<<4);//enalbling timer 0 interrupt
    T0TCR = 0x01; //reset timer control register
}*/
void adc_isr_init(void)
{
  
  VICIntSelect|=(1<<18);//selecting AD0 from VICIntselect register  
  VICIntEnable|=(1<<18);//enabling AD0  from VICIntenable register  
  VICVectCntl1=0X20|18;//AD0 source to interrupt controller  VIC
  VICVectAddr1=(unsigned)adc_schedule;  //passing irq address to VIC   
  PINSEL1|=(1<<22); // P0.27      
  AD0CR=0X00000001; //selecting AD0.0 on SEL pin from control register
  AD0CR|=(1<<9); //setting CLKDIV in ADC control register
  AD0CR|=(1<<21);//making AD0 operational  
  //AD0STAT|=(1<<16);
}
void adc_schedule()
{
   
   AD0CR|=(1<<24); //to start conversion
   while(!(AD0GDR & (1<<31))); // waiting data conversion to get complete
   result=((!(AD0GDR>>6) && 0X3FF)); //getting data from bit 6:15 of AD0GDR  
   AD0INTEN|=(1<<0);//generating interrupt on completion of conversion on AD0.0 
   //LCD_WriteString("Completion");
   VICVectAddr=0x000;    //end of all ISRs
}
void conversion()
{
  int val;
  unsigned int x,y,z;
  float stepsize;//stepsize
  stepsize = 0.0032;
  val=result*stepsize*100; 
  x=(val%10);
  y=(val%100)/10;
  z=val/100;
  LCD_WriteString("Voltage");
  LCD_WriteString("=");
  LCD_WriteChar(x+48);
  LCD_WriteString(".");
  LCD_WriteChar(y+48);
  LCD_WriteChar(z+48);
  LCD_WriteString("V"); 
}
void initLCD(void)
{
    IODIR0 = 0xFF;              //P0.0 to P0.7 configured as Output - Using 8 Bit mode
    IODIR1 = (1<<16) | (1<<17);        //P1.16 and P1.17 configured as Output - Control Pins
    IOPIN0 = 0x0;               //Reset Port0 to 0.   
    IOPIN1 = 0x0;               //Reset Port1 to 0 - Which also makes RS and Enable LOW.
 
                                //LCD Initialization Sequence Now starts
    delay(2);                   //Initial Delay
    LCD_Cmd(0x38);              //Function Set Command
    delay(2);
    LCD_Cmd(0x0F);          //Display Switch Command : Display on , Cursor on , Blink on
            delay(2);//LCD_Cmd(0x06);           //Input Set : Increment Mode 
    LCD_Cmd(0x01);          //Screen Clear Command , Cursor at Home
                //Not required the 1st time but needed to reposition the cursor at home after Clearing Screen 
                                //Done!
}
void enable(void)
{
    delay(1);
    IOPIN1 |=  (1<<17);//Enable=High
    delay(1);
    IOPIN1 &= ~(1<<17);//Enable=Low
    delay(1);
}
 
void LCD_WriteChar(char c)
{
    IOPIN1 |= (1<<16); //Switch to Data Mode
    IOPIN0 = (int) c; //Supply Character Code
    enable(); //Pulse Enable to process it
}
 
void LCD_WriteString(char * string)
{
    int c=0;
    while (string[c]!='\0')
    {
        LCD_WriteChar(string[c]);
        c++;
    }
}
        
void LCD_Cmd(unsigned int cmd)
{
    IOPIN1 = 0x0; //Enter Instruction Mode
    IOPIN0 = cmd; //Supply Instruction/Command Code
    enable(); //Pulse Enable to process it
}
 
void sleep_mode()
   {
      PCON=0X01;
   }
 
 
int main()
{
  initLCD();
  adc_isr_init();
 
  conversion();
  while(1)
  {
    sleep_mode();
  }
  
}