xtest11_3.c

AT91sam7s 256 B/D example

/* ========================================================================== */
/*  Xtest11_3.c : Multiple Interrupt Program(RTT & PIT in System Controller)  */
/* ========================================================================== */
/*			  Designed and programmed by Duck-Yong Yoon in 2007.  */

#include "AT91SAM7S256.h"
#include "lib_AT91SAM7S256.h"
#include "OK7S256ads.h"

volatile unsigned int RTT_flag=0;		// RTT interrupt flag
volatile unsigned int PIT_flag=0;		// PIT interrupt flag

void SYS_ISR(void)				/* RTT & PIT interrupt service routine */
{
  if(AT91F_RTTGetStatus(AT91C_BASE_RTTC) & 0x0002) // RTT interrupt ?
    { RTT_flag ^= 0x01;				// toggle RTT_flag(2Hz/2 = 1Hz)
      if(RTT_flag == 1)				// if RTT_flag=1, LED1 on
        LED_on(LED1);
      else					// if RTT_flag=0, LED1 off
        LED_off(LED1);
    }
  else if(AT91F_PITGetStatus(AT91C_BASE_PITC) & 0x0001) // PIT interrupt ?
    { AT91F_PITGetPIVR(AT91C_BASE_PITC);	// clear PITS
      PIT_flag ^= 0x01;				// toggle PIT_flag(4Hz/2 = 2Hz)
      if(PIT_flag == 1)				// if PIT_flag=1, LED2 on
        LED_on(LED2);
      else					// if PIT_flag=0, LED2 off
        LED_off(LED2);
    }
}

int main(void)
{
  MCU_initialize();				// initialize AT91SAM7S256 & kit
  Delay_ms(50);					// wait for system stabilization
  LCD_initialize();				// initialize text LCD module

  LCD_string(0x80, "RTT(LED1) = 2 Hz");		// display title
  LCD_string(0xC0, "PIT(LED2) = 4 Hz");
  Beep();

  LED_off(LED2|LED1);				// LED2~LED1 off

  AT91F_RTTC_CfgPMC();				// initialize RTT
  AT91F_RTTRestart(AT91C_BASE_RTTC);		// clear and restart RTT
  AT91F_RTTSetPrescaler(AT91C_BASE_RTTC,16384);	// 32.768kHz/16384 = 2Hz
  AT91F_RTTSetRttIncINT(AT91C_BASE_RTTC);	// initialize RTT interrupt

  AT91F_PITC_CfgPMC();				// initialize PIT
  AT91F_PITInit(AT91C_BASE_PITC,1,48);		// enable and initialize PIT
  AT91F_PITSetPIV(AT91C_BASE_PITC,750000-1);	// 48MHz/16/750000 = 4Hz
  AT91F_PITEnableInt(AT91C_BASE_PITC);		// initialize PIT interrupt

  AT91F_AIC_ConfigureIt(AT91C_BASE_AIC,AT91C_ID_SYS,7,1,SYS_ISR); // set interrupts
  AT91F_AIC_EnableIt(AT91C_BASE_AIC,AT91C_ID_SYS);

  while(1);					// wait for interrupts
}