What's the interrupt latency and/or overhead when using DT-Ints?

[HenrikOlsson]

I was going to say that the actual overhead can and will be different depending on what commands your program is using but compared to what's already there we're not talking about much. If it's really critical then my suggestion is to either measure it yourself or use the worst case number, which Pedja says is 280 instructions when not using LONGs.

As for declaring the interrupt type as ASM while still using DT-ints the total (measured) overhead is around 7.6us - a difference of 8us or 128 instruction cycles. But if you're going to write the interrupt handler in assembly then you don't really need DT-Ints anyway and the overhead will become very small.

Finally, the measurement shown here are all approximate, counting instruction cycles is Always a more accurate way, this was juse meant to visually show what's going on and put some sort of number on it for people who may be wondering.

/Henrik.