I have some code that relies on the input capture timer value.
I assume the timer value (as defined by the pre-scaler etc) is not affected by other code running i.e. it is updated every nth clock regardless of what instruction is next?
If you want code or more detail ask in comments and I will post code.
The way IC typically works is completely independent from the CPU and what instructions you are running.
The timer runs freely between the start and end input capture events. At the moment of capture the timer value is frozen into another register. The interrupt is then triggered. You then read that frozen value. It doesn't matter how long after the end event the interrupt executes, or what you do in that interrupt, the captured time is still the same.
I assume the timer value (as defined by the pre-scaler etc) is not affected by other code running i.e. it is updated every nth clock regardless of what instruction is next?
yes, unless your code writes to the registers involved.
