Purchasing the 2009 controller

[jhersh]

Originally Posted by Danny Diaz

I was actually wondering if anyone actually had the opportunity to read the technical specifications for the cRIO and realized there ARE NO INTERRUPTS SUPPORTED ON THE cRIO. I'm guessing not.

Instead of having interrupts, you have an FPGA - the FPGA is a pure polling mechanism, but it's extremely FAST. So, instead of having interrupts taking time away from the main processor, you've got an external unit managing a fast polling strategy for reading external sensors.

-Danny

This is not quite accurate. The FPGA does have the ability, as long as the code is compiled in, to interrupt the PPC. In most cases where interrupts were used in the past, it is true that interrupts will no longer be necessary, due to the features being added to the FPGA image for 2009 for handling the things most teams do. This does not mean that it is impossible. Perhaps Danny meant that interrupts are not supported without support built into the FPGA. All user interrupts must come from the FPGA. The interrupts could be programmed to come from user I/O or from a timer or various other places. Here is a document that describes it.