how to use external signal on nios2 in software

I have add a pin namely “enb” on nios processor as display in attached print-screen, every time this pin got high pulse. my IORD_..function read this pulse and start doing my further job.

i have seen through oscilloscope that enb pulse is keep coming but my software routine could not read this pin ...it always says “enb = 0”

Rate of change of this enb pin is (1/8)mhz.

how do i use this external pin to my software....?

p { margin-bottom: 0.21cm; }

//this is the system.h contents with respect to the added enb input pin

/*

* pio_in_enb configuration

*

*/

#define ALT_MODULE_CLASS_pio_in_enb altera_avalon_pio

#define PIO_IN_ENB_BASE 0x10001560

#define PIO_IN_ENB_BIT_CLEARING_EDGE_REGISTER 0

#define PIO_IN_ENB_BIT_MODIFYING_OUTPUT_REGISTER 0

#define PIO_IN_ENB_CAPTURE 0

#define PIO_IN_ENB_DATA_WIDTH 1

#define PIO_IN_ENB_DO_TEST_BENCH_WIRING 0

#define PIO_IN_ENB_DRIVEN_SIM_VALUE 0x0

#define PIO_IN_ENB_EDGE_TYPE "NONE"

#define PIO_IN_ENB_FREQ 82500000u

#define PIO_IN_ENB_HAS_IN 1

#define PIO_IN_ENB_HAS_OUT 0

#define PIO_IN_ENB_HAS_TRI 0

#define PIO_IN_ENB_IRQ -1

#define PIO_IN_ENB_IRQ_INTERRUPT_CONTROLLER_ID -1

#define PIO_IN_ENB_IRQ_TYPE "NONE"

#define PIO_IN_ENB_NAME "/dev/pio_in_enb"

#define PIO_IN_ENB_RESET_VALUE 0x0

#define PIO_IN_ENB_SPAN 16

#define PIO_IN_ENB_TYPE "altera_avalon_pio"

//this is my software routine which tried to read incoming enb pulse.....

do

{

enb = IORD_ALTERA_AVALON_PIO_DATA(PIO_IN_ENB_BASE); //Check For Rx Interrupt

if (enb)

{

//doing my job

}

printf(“\nenb = %d”,enb);

} while (my condition));

kaushal