Intel 80C196NU User Manual

10-25

void poll_epa0()
{
 if(checkbit(int_pend, EPA0_INT_BIT))

{
/*  Insert user code for event channel 0 here. */
/*  Since this event is absolute and re-enabled, no polling is neccessary.*/

     clrbit(int_pend, EPA0_INT_BIT);

}

}

void main(void)
{
/* Initialize the timers before using the epa */
init_timer1();
init_epa0();
/*  EPA events can be serviced by polling int_pend or epa_pend. */
while(1)

{
poll_epa0();
}

}

This example C program demonstrates an EPA capture event. It sets up EPA channel 0 to capture
edges (rising and falling) on the EPA0 pin. The program also shows how to set up an the EPA
interrupt. You can add your own code for the interrupt service routine. 

#pragma model(EX)
#include <80c196np.h>

#define  COUNT_ENABLE

0x80

#define  COUNT_UP

0x40

#define  CLOCK_INTERNAL 

0x00

#define  DIVIDE_BY_1 

0x00

#define  CAPTURE            

0x00

#define  BOTH_EDGE 

0x30

#define  USE_TIMER1

0x00

#define  EPA0_INT_BIT 

7

void init_epa0()
{
 epa0_con = CAPTURE 

¦

BOTH_EDGE 

¦

USE_TIMER1;

 setbit(p1_reg, 0); /*  int reg  */
 setbit(p1_dir, 0); /*  make input pin  */
 setbit(p1_mode, 0);/*  select EPA mode  */
 setbit(int_mask, EPA0_INT_BIT);/*  unmask EPA interrupts  */
}

#pragma interrupt(epa0_interrupt=EPA0_INT_BIT)
void epa0_interrupt()
{
 unsigned int time_value;