/*programe for tomer 0 interrupt using lpc2138*/
#include <lpc213x.h>
#define MR0I (1<<0) //Interrupt When TC matches MR0
#define MR0R (1<<1) //Reset TC when TC matches MR0
#define DELAY_MS 100 //0.5 Second(s) Delay
#define PRESCALE 60000 //60000 PCLK clock cycles to increment TC by 1
//void initClocks(void);
void initTimer0(void);
__irq void T0ISR(void);
int main(void)
{
//initClocks(); //Initialize CPU and Peripheral Clocks @ 60Mhz
initTimer0(); //Initialize Timer0
IO0DIR = 0xFFFFFFFF; //Configure all pins on Port 0 as Output
IO0PIN = 0x0;
T0TCR = 0x01; //Enable timer
while(1); //Infinite Idle Loop
//return 0; //normally this wont execute ever
}
void initTimer0(void)
{
/*Assuming that PLL0 has been setup with CCLK = 60Mhz and PCLK also = 60Mhz.*/
//----------Configure Timer0-------------
T0CTCR = 0x0;
T0PR = PRESCALE-1; //(Value in Decimal!) - Increment T0TC at every 60000 clock cycles
//Count begins from zero hence subtracting 1
//60000 clock cycles @60Mhz = 1 mS
T0MR0 = DELAY_MS-1; //(Value in Decimal!) Zero Indexed Count - hence subtracting 1
T0MCR = MR0I | MR0R; //Set bit0 & bit1 to High which is to : Interrupt & Reset TC on MR0
//----------Setup Timer0 Interrupt-------------
VICVectAddr4 = (unsigned )T0ISR; //Pointer Interrupt Function (ISR)
VICVectCntl4 = 0x20 | 4; //0x20 (i.e bit5 = 1) -> to enable Vectored IRQ slot
//0x4 (bit[4:0]) -> this the source number - here its timer0 which has VIC channel mask # as 4
//You can get the VIC Channel number from Lpc214x manual R2 - pg 58 / sec 5.5
VICIntEnable = 0x10; //Enable timer0 int
T0TCR = 0x02; //Reset Timer
}
__irq void T0ISR(void)
{
long int regVal;
regVal = T0IR; //Read current IR value
IO0PIN = ~IO0PIN; //Toggle all pins in Port 0
T0IR = regVal; //Write back to IR to clear Interrupt Flag
VICVectAddr = 0x0; //This is to signal end of interrupt execution
}