kobilica:
dilej() is just delay function. Works fine.
Depending on how it is written, delay functions might not work inside an ISR. Sadly you haven't shown us the dilej function.
DuaneB:
I might be wrong, but does the spi library rely on interrupts ?
No - SPI.transfer is so fast that attempting to use interrupts would be slower.
@op - show the whole thing, not just snippets.
kobilica:
Ok, I typed sei() in the beggining of ISR function, but it doesn't work. Or did I misunderstood you?
Don't do that. Enabling interrupts inside an ISR is not a good idea.