[ratdude747]

Originally Posted by Greg McKaskle

I'm pretty sure the Periodic tasks have been there since the beginning. The Vision task is basically the same thing, but specialized to be throttled by camera images showing up.

Joystick values show up when new control packets arrive. So the teleop is designed to be a great place to catch the latest joystick "events" and respond to them with the least latency. For some operations, where the joystick is the most important trigger and the response is quick, teleop is a great place to put the code.

If the code is also triggered by time, takes more than 20ms to complete the operation, or includes sensor measurement to complete a control loop, Periodic may be a better place. As ratdude said, using teleop joystick data to update set points and time to run the control algorithm is a pretty common situation. That naturally minimizes the latency of both inputs. Note that it is pretty easy to read the joystick wherever you like, so this can often simplify some of the communication between Periodic and teleop and not require using a global just to hold the joystick state.

Greg McKaskle

The Main reason I always used global variables was to keep teleop things in teleop. This does two things; it means that if you ever want to change that value during autonomous, it is an easy switch; it also means that if a random act of god caused a controller issue during autonomous, no problems would occur (like if a ball being tossed in the stands randomly bounced and hit a joystick).

Consider it a matter of programmer's preference... its how I learned to write code and it has always worked for me.