Compact rio not being able to use C

[Roboj]

Originally Posted by Dave Flowerday

Brad,
I guess I'm trying to find out how the "robot disable" function is actually implemented in the new system. I.e. what hardware is generating the PWM signal, and what conditions cause that hardware to stop generating and therefore shut down the motors? Is that hardware being updated by some sort of system (non-user modifiable) task?

Hi Dave,
The watchdog is implemented in the FPGA. Therefore, it is a non-modifiable and non-crashable task. If the watchdog isn't strobed at a minimum rate, the I/O (which is also controlled by the FPGA) will go to safe mode. Therefore, PWMs are set to the proper value to halt the motors. As mentioned in Brad's message, there are ways that the strobing of the watchdog can continue to run while debugging if that is desired. As Brad mentioned, there are some disadvantages/hazards to allowing this also.

Besides not wanting to throw too much technology at the participants at once, this is another reason we aren't allowing you to re-program the FPGA this year. We can't risk teams accidentally disabling the safety features until there are some features added to LabVIEW FPGA to let you do this safely.