ISR durtation - what is acceptable

What do you think of a periodic interrupt (1 millisecond) consuming about 45 microsecond on a LPC24xx chip running at 64 MHz ? Does this make the system not suitable for certain means?

 RE: ISR durtation - what is acceptable

Not a problem unless you have specific other needs that must be serviced quicker.

Only you know what real-time requirement your specific project has.

 RE: Does this make the system not suitable for certain means?

Obviously, Yes - it makes it unsuitable for anything that can't tolerate the CPU being "hogged" for 45 microseconds every millisecond!