Documentation on the RoboRIO HAL

[Thad House]

Is there any documentation on the new RoboRIO HAL interface. I would like to look into creating a .Net library, and documentation would make the task much easier.

[Quantum Byte]

Nope. I managed to get one working though.

Basically, you just create a PWM object. Then, call the get() function, and that will return a bool/boolean of if a magnet is detected.

[fsilberberg]

Originally Posted by Thad House

Is there any documentation on the new RoboRIO HAL interface. I would like to look into creating a .Net library, and documentation would make the task much easier.

We don't have any official documentation on the HAL. Your best bet is to take a look at the source for C++ and see how it interacts with the HAL. If you have questions, you can send me a message, I'd be happy to help. It can definitely be confusing to look at.

[Thad House]

Originally Posted by fsilberberg

We don't have any official documentation on the HAL. Your best bet is to take a look at the source for C++ and see how it interacts with the HAL. If you have questions, you can send me a message, I'd be happy to help. It can definitely be confusing to look at.

Thanks. I'll definitely take a look into that. It will most likely be a summer project, but figured I could get started work on it now. When the season is over ill probably borrow one of our RoboRIOs to see if mono will even run on it, and if it will run fast enough on it.

One thing I remember reading is that the OS on the RoboRIO is softFP. Is that true? Seems like that would cause performance issues, even with the current languages.

[byteit101]

Originally Posted by Thad House

One thing I remember reading is that the OS on the RoboRIO is softFP. Is that true? Seems like that would cause performance issues, even with the current languages.

yes, but softfp != soft

softfp uses the hardware floating point unit, but is conformant with the software floating point abi (soft). While softfp and hard both use the hardware floating point unit, they are not abi compatible.

[Thad House]

Originally Posted by byteit101

yes, but softfp != soft

softfp uses the hardware floating point unit, but is conformant with the software floating point abi (soft). While softfp and hard both use the hardware floating point unit, they are not abi compatible.

Ok. I did find a precompiled Mono for armv7-vfp, so that should make doing this much easier. I was able to get the header files working in c#, and I'll have to ask the RobotPy people if I can use their precompiled HAL they use for python, but if possible this project shouldnt be too hard.

[Peter Johnson]

Originally Posted by Thad House

Ok. I did find a precompiled Mono for armv7-vfp, so that should make doing this much easier. I was able to get the header files working in c#, and I'll have to ask the RobotPy people if I can use their precompiled HAL they use for python, but if possible this project shouldnt be too hard.

Of course you can use our precompiled HAL! The shared library is actually compiled as part of the official wpilib source build (thanks to a patch I submitted), but it's not distributed/installed on the roborio by default, which is why we're hosting it ourselves for installation.

[Thad House]

Originally Posted by Peter Johnson

Of course you can use our precompiled HAL! The shared library is actually compiled as part of the official wpilib source build (thanks to a patch I submitted), but it's not distributed/installed on the roborio by default, which is why we're hosting it ourselves for installation.

Thats great. I hope to have this up early summer. The only thing I need to figure out is how to get the few the custom structures to work. Everything else will most likely just take work and time (plus a RoboRIO for me to test this on that doesnt interfere with the team.)

[fsilberberg]

Yes, it is softfp. We haven't noticed any performance issues with the libraries as of now.