/*************************************************************************/	
/*                                                                       */
/*			External Interrupt Demo Program                              */
/*														                 */
/*          Input: J6-10 (p0.3) as EINT1 external interrupt input        */
/*                 (falling-edge trigger)                                */
/*                                                                       */
/*                 Note: external interrupt inputs can be set as level   */
/*                       or edge trigger depends on EXTMODE setting and  */
/*                       can be set as high or low active in EXTPOLAR.   */
/*                       EXTPOLAR default setting is low active.         */
/*                                                                       */
/*          Outputs: J6-11 (p0.8) Red LED; J6-12 (p0.9) Green LED        */
/*                                                                       */
/*************************************************************************/
/*                                                                       */
/*			ARM CPU: Philips LPC2138								     */
/*			Crystal clock: 11.0592 MHz								     */
/*			Serial port baudrate: 57600								     */
/*			Programming tool: KEIL uVision3 RealView for ARM 		     */			
/*																	     */
/*************************************************************************/
#include <lpc21xx.h>

extern void init_timer_Eint(void);

#define RED_LED			0x00000100	//define p0.8 as Red LED output
#define GREEN_LED		0x00000200	//define p0.9 as Green LED output

#define NEWLINE sendchar(0x0a); sendchar(0x0d)

//define global variables
long timeval;
long  exint;

//===============================
void  Init_Serial_A(void) {  
	U0LCR = 0x83;	//8 bit length ,DLAB=1	           
   	U0DLL = 0x0F;	//Pclk/(16*baudrate)=(11059200 x 5)/(4 x 16 x 57600);
   	U0DLM = 0x00;
   	U0LCR = 0x03;    //DLAB=0
}

char getchar(void) {
	volatile char ch = '0';

  	while ((U0LSR&0x1)==0) // wait until  receive a byte
    ;
  	ch = U0RBR;         // receive character

  	return ch;
}

void sendchar(char ch) {
	while( (U0LSR&0x40)==0 );
    
 	U0THR  = ch;                     // Transmit next character
}

int  print(char *p) { 
	while(*p!='\0') {
      sendchar(*p++);
   }
   return(0);
}

void putint(int count) { 
	sendchar('0' + count/10000);
	sendchar('0' + (count/1000) % 10);
	sendchar('0' + (count/100) % 10);
	sendchar('0' + (count/10) % 10);
	sendchar('0' + count % 10);
}

int read_sensor(int channel)
{
	int temp;
         
	ADCR=0x1<<channel;
	ADCR|=0x1200200;

	while(((temp=ADDR)&0x80000000)==0);
	temp>>=6;
	temp&=0x3ff;//TEMP IS 0-3V PRESICION IS 1024

	return (temp*33);
}

int  main(void)
{

 PINSEL0 = 0x00000005;		// set p0.0 to TXD0, p0.1 to RXD0 and the rest to GPIO
 PINSEL0 |= 0x000000C0;		// set p0.3 as EINT1 external interrupt input
 
 Init_Serial_A();			// Init COM port
 init_timer_Eint();			// Init TIMER 0	& EINT1
 
 NEWLINE;
 print("======================================================================="); NEWLINE;
 print("*                                                                     *"); NEWLINE;
 print("*         CUHK Computer Science and Engineering Department            *"); NEWLINE;
 print("*                  LPC2138 ARM Board (2009)                           *"); NEWLINE;
 print("*                                                                     *"); NEWLINE;
 print("*                  External Interrupt Demo (2009)                     *"); NEWLINE;
 print("*                                                                     *"); NEWLINE;
 print("======================================================================="); NEWLINE;
 NEWLINE;
 

 //set p0.8 and p0.9 as output
 IO0DIR|=RED_LED;
 IO0DIR|=GREEN_LED;

 	while(1) {
	}
}
 
void __irq  IRQ_Exception()
{
  	timeval++;

	//Blink the Red LED
	if((timeval%2)==0) IO0SET|=RED_LED;
	else IO0CLR|=RED_LED;

    T0IR = 1;                              	// Clear interrupt flag
    VICVectAddr = 0;                       	// Acknowledge Interrupt
}

void __irq IRQ_Eint1()
{  
    
   exint++;

   //Blink the Green LED
	if((exint%2)==0) IO0SET|=GREEN_LED;
	else IO0CLR|=GREEN_LED;

   EXTINT = 0x02;				// Clear EINT1 flag
   VICVectAddr = 0;             // Acknowledge Interrupt   
}		


/* Setup the Timer Counter 0 Interrupt */
void init_timer_Eint (void) {
	T0PR = 0;								// set prescaler to 0
	T0MR0 =1382400;							// set interrupt interval to 1mS
											// Pclk/10Hz = (11059200 x 5)/(4 x 1000)
    T0MCR = 3;                             	// Interrupt and Reset on MR0
    T0TCR = 1;                             	// Timer0 Enable
	VICVectAddr0 = (unsigned long)IRQ_Exception;  	// set interrupt vector in 0
    VICVectCntl0 = 0x20 | 4;                    // use it for Timer 0 Interrupt
    VICIntEnable = 0x00000010;                  // Enable Timer0 Interrupt

	EXTMODE=0x02;							// set EINT1 as edge trigger
	VICVectAddr1 = (unsigned long)IRQ_Eint1;  	// set interrupt vector in 1
	VICVectCntl1 = 0x20 | 15;                   // use it for EINT1 Interrupt
    VICIntEnable |= 0x00008000;			// Enable EINT1 interrupt
    EXTINT = 0x02;				// Clear EINT1 flag
}