Nios II timer triggered interrupt

Altera_Forum · ‎08-01-2016

Hello I am trying to implement a timer triggered interrupt and I can not seem to get it to work and I don't really know what I am doing wrong.

Here is how it looks in Qsys where I have the interval timer component and it is connected to the IRQ.

http://www.alteraforum.com/forum/attachment.php?attachmentid=12520&stc=1

#include "system.h"
# include "sys/alt_stdio.h"
# include "sys/alt_irq.h"
# include "altera_avalon_pio_regs.h"
# include "altera_avalon_timer_regs.h"
const unsigned char sevenSegData = {0x40, 0x79, 0x24, 0x30, 0x19,
                                      0x12, 0x02, 0x78,0x00, 0x10, 0x08,
                                      0x03,0x46, 0x21, 0x06, 0x0E, 0x3F};
unsigned short switches;
unsigned char keys;
void timer_0_ISR(void *context)
{
   // clear irq status in order to prevent retriggering
   IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE, 0);
   alt_putstr("ISR TEST!\n");
}
int main()
{ 
     // Timer initialization
    IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_0_BASE, ALTERA_AVALON_TIMER_CONTROL_CONT_MSK
                                                 | ALTERA_AVALON_TIMER_CONTROL_ITO_MSK);
    IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_0_BASE, 0);    // Clear IRQ status just in case..
    IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_0_BASE, ALTERA_AVALON_TIMER_PERIODL_MSK);
    IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_0_BASE, ALTERA_AVALON_TIMER_PERIODH_MSK);
    // Register the ISR for timer event
    alt_ic_isr_register(TIMER_0_IRQ_INTERRUPT_CONTROLLER_ID, TIMER_0_IRQ, timer_0_ISR, 0, 0x0);
    // Start timer
    IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_0_BASE, 0x0007);
    /* Event loop never exits. */
    while (1)
    {
        switches = IORD_ALTERA_AVALON_PIO_DATA(SWITCH_BASE);
        keys      = IORD_ALTERA_AVALON_PIO_DATA(KEY_BASE);
        IOWR_ALTERA_AVALON_PIO_DATA(LED_RED_BASE, switches);
        IOWR_ALTERA_AVALON_PIO_DATA(HEX0_BASE, sevenSegData);
    }
  return 0;
}

Altera_Forum · ‎08-05-2016

It actually works... I thought that the ALTERA_AVALON_TIMER_PERIODL_MSK & ALTERA_AVALON_TIMER_PERIODH_MSK would've been configured according to the Qsys setting but apparently they didn't so I had an 90 sec overflow and I didn't notice it until I actually went up and left my workstation and came back to see multiple messages from the ISR.