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Altera_Forum's avatar
Altera_Forum
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9 years ago

pio interrupt not working

Hii ,

I'm new to the nios.

i have a push button in my project which is connected to the pio ,which shouid generate interrupt whenever its get pressed.

its falling edge irq.

but interrupt is not getting generated.

code is as bellow:# for initialization

IOWR_ALTERA_AVALON_PIO_EDGE_CAP(START_STOP_KEY_BASE, 0x0);

alt_ic_isr_register(START_STOP_KEY_IRQ_INTERRUPT_CONTROLLER_ID , START_STOP_KEY_IRQ, Status_chng, NULL, 0x0);

# ISR

inChL = IORD_ALTERA_AVALON_PIO_EDGE_CAP(START_STOP_KEY_BASE);

IOWR_ALTERA_AVALON_PIO_EDGE_CAP(START_STOP_KEY_BASE, 0x0);

IORD_ALTERA_AVALON_PIO_EDGE_CAP(START_STOP_KEY_BASE);

edge cap read is always high .

i tried enabling irq with hal function also but no result .

controller is not going to isr at all.

What m i missing here or if someone have some sample code of pio interrupt based on edge plz share...

Thanks and regards

Ankur

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    9 years ago

    Have you checked the PIO settings in the SOPC builder/Qsys?

    this example is from the Nios II software developers handbook

    Example 8–1. An ISR to Service a Button PIO Interrupt

    # include "system.h"

    # include "altera_avalon_pio_regs.h"

    # include "alt_types.h"

    # ifdef ALT_ENHANCED_INTERRUPT_API_PRESENT

    static void handle_button_interrupts(void* context)

    # else

    static void handle_button_interrupts(void* context, alt_u32 id)

    # endif

    {

    /* Cast context to edge_capture's type. It is important that this

    be declared volatile to avoid unwanted compiler optimization. */

    volatile int* edge_capture_ptr = (volatile int*) context;

    /*

    * Read the edge capture register on the button PIO.

    * Store value.

    */

    *edge_capture_ptr =

    IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE);

    /* Write to the edge capture register to reset it. */

    IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0);

    /* Read the PIO to delay ISR exit. This is done to prevent a

    spurious interrupt in systems with high processor -> pio

    latency and fast interrupts. */

    IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE);
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    9 years ago

    Hello Ulika,

    Thanks for your reply.

    pio setting looks good.

    and i have tried with this example but still its not working....