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IAR Embedded Workbench for RX 5.20

Simulating a simple interrupt

In this section:

This example demonstrates the method for simulating a timer interrupt. However, the procedure can also be used for other types of interrupts.

To simulate and debug an interrupt:

  1. Assume this simple application which contains an interrupt service routine for a timer, which increments a tick variable. The main function sets the necessary status registers. The application exits when 100 interrupts have been generated.

    #include <sdtio.h>
#include "ior5f56108.h"
#include <intrinsics.h>

volatile int ticks = 0;
void main (void)
{
 /* Add your timer setup code here */
 
 __enable_interrupt();  /* Enable interrupts */
 
 while (ticks < 100);   /* Endless loop */
 printf("Done\n");
}

/* Timer interrupt service routine */
#pragma vector = INT_TIMER
__interrupt void basic_timer(void)
{
 ticks += 1;
}

  2. Add your interrupt service routine to your application source code and add the file to your project.

  3. Choose Project>Options>Debugger>Setup to see the name and location of the device description file that is being used. Open it to define an interrupt that C-SPY can simulate. The device description file contains the information you need.

  4. Build your project and start the simulator.

  5. Choose Simulator>Interrupt Configuration to open the Interrupt Configuration window. Right-click in the window and select Enable Interrupt Simulation on the context menu. For the timer example, verify these settings:

    Option

    Settings

    Interrupt

    INT_TIMER

    First activation

    4000

    Repeat interval

    2000

    Hold time

    10

    Probability (%)

    100

    Variance (%)

    0

    Table 27. Timer interrupt settings 


    Click OK.

  6. Execute your application. If you have enabled the interrupt properly in your application source code, C-SPY will:

    • Generate an interrupt when the cycle counter has passed 4000

    • Continuously repeat the interrupt after approximately 2000 cycles.

  7. To watch the interrupt in action, choose Simulator>Interrupt Log to open the Interrupt Log window.

  8. From the context menu, available in the Interrupt Log window, choose Enable to enable the logging. If you restart program execution, status information about entrances and exits to and from interrupts will now appear in the Interrupt Log window.

    For information about how to get a graphical representation of the interrupts correlated with a time axis, see Timeline window—Interrupt Log graph.