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Unread 27-07-2015, 23:49
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Re: Which sensors should be used throughout the robot?

Quote:
Originally Posted by AustinSchuh View Post
Interrupts work, but have about a 100 uS delay between when the interrupt triggers and it gets captured. That is assuming that you are running the interrupt code in C++, have it in a thread, and have bumped the RT priority up of that thread so that it is very high priority. We have used them to capture the encoder count when we pass by a hall effect (or when we see an index pulse).
What kind of delay is there on the interrupt system if you are running everything default, no thread priorities, on Java? I feel like 0.1-1 ms is more than a fast enough response time for virtually every FRC application, considering that other methods like CAN can have >10ms of cycle time, but I know think I remember hearing that you guys had overclocked the CAN rates too.

Also, I'm not super familiar with JNI or the fancier parts of WPILIB, but it looks to me like you just pass your Handler function into the FGPA, which I assume would be watching it on a specified thread already. It might be different if you are working with WPILIBC though, since WPILIBJ just stops once you hit the native calls and I don't remember where/if you can look up with implementation.
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