xtest03_6.c

AT91sam7s 256 B/D example

/* ========================================================================== */
/*	      Xtest03_6.c : Test Time-Delay Function by Hardware	      */
/* ========================================================================== */
/*			  Designed and programmed by Duck-Yong Yoon in 2007.  */

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

volatile unsigned int ms_count=0;		// ms count by PIT interrupt

void PIT_ISR(void)				/* PIT interrupt service routine */
{
  AT91F_PITGetPIVR(AT91C_BASE_PITC);		// clear PITS
  ms_count++;					// increment ms_count
}

void PIT_initialize(void)			/* initialize PIT and interrupt */
{
  AT91F_PITC_CfgPMC();				// enable peripheral clock for PIT
  AT91F_PITInit(AT91C_BASE_PITC,1,48);		// enable and initialize PIT
  AT91F_PITSetPIV(AT91C_BASE_PITC,3000-1);	// set period for PIT interrupt
  
  AT91F_PITDisableInt(AT91C_BASE_PITC);		// initialize PIT interrupt
  AT91F_AIC_ConfigureIt(AT91C_BASE_AIC,AT91C_ID_SYS,7,1,PIT_ISR);
  AT91F_AIC_EnableIt(AT91C_BASE_AIC,AT91C_ID_SYS);
}

void HW_delay_ms(unsigned int ms)		/* ms delay by PIT interrupt */
{
  if(ms == 0) return;

  ms_count = 0;					// start time
  AT91F_PITEnableInt(AT91C_BASE_PITC);		// enable PIT interrupt
  while(ms_count < ms);				// wait for ms

  AT91F_PITDisableInt(AT91C_BASE_PITC);		// disable PIT interrupt
}

int main(void)
{ unsigned int i;

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

  LCD_string(0x80, " S/W Time Delay ");		// display title
  LED_off(LED2|LED1);				// LED2~LED1 off

  PIT_initialize();				// initialize PIT and interrupt

  while(1)
    { LCD_string(0xC0, " 10ms delay test");	// output pulse by 10ms delay
      Beep();
      for(i=0; i<500; i++)
        { LED_on(LED2);				// LED2 on 
          HW_delay_ms(10);
          LED_off(LED2);			// LED2 off
          HW_delay_ms(10);
        }

      LCD_string(0xC0, "100ms delay test");	// output pulse by 100ms delay
      Beep();
      for(i=0; i<50; i++)
        { LED_on(LED2);				// LED2 on 
          HW_delay_ms(100);
          LED_off(LED2);			// LED2 off
          HW_delay_ms(100);
        }

      LCD_string(0xC0, "500ms delay test");	// output pulse by 500ms delay
      Beep();
      for(i=0; i<10; i++)
        { LED_on(LED2);				// LED2 on 
          Delay_ms(500);
          LED_off(LED2);			// LED2 off
          Delay_ms(500);
        }
    }
}