Debugging by bsing SW interrupts instead of HW interrupts

Just make a little interrupt generator, could be just a pushbutton, a Schmitt inverter, a resistor and a cap (depending on how your interrupts work), and tag that onto the appropriate interrupt signal. Push the button, and step your way through the bugs!

Paul Burke

In X86 32-bit assembler, you can test your interrupt routine by:

PUSHFD CALL FAR isr_address

or

PUSHFD PUSH CS CALL NEAR isr_address

But because your hardware isn't actually signalliung an interrupt, register reads in the ISR may not give what you'd expect, so this will really just check the prolog/epilog code of your IST handler.

It would be preferable to actually trigger the hardware interrupt proper. If you need to pull a line up or down, just have a 10k resistor running to Vcc or ground and touch it to the relevant line. Presuming this is practicable of course.

S/W ints are no replacement for H/W ints, but are generally used to supply a different functionality.

Regards, Alfie.

Externally triggering of interrupt pin seems to be practical . I will try.Thank you.

Husnu Ayduk

snipped-for-privacy@blueyonder.co.uk yazdi:

Be a bit careful - using a switch or some other manual means will result in bounce, and you're likely to see multiple interrupts. You might consider using some external logic to ensure that your IRQ pin only sees a single transition. You could for instance use a 555 to generate a regular LF IRQ, and use a switch to enable/disable the 555. Just a thought.

Steve