Do you make a program for the Cortex, or can you download a program directly to the joystick?
All programs are sent to and stored on the Cortex microcontroller; the Joystick simply passes data (such as joystick values, joystick button values, and joystick accelerometer data) to the Cortex for processing. It also acts as a bridge between a Cortex and a computer (if using the Programming Hardware Kit with a VEXNext connection to a Cortex) or a competition switch/field (if plugged in via the Competition port).
For information on creating and using a remote control (VEXNet) ROBOTC program on a Cortex, take a look through the ‘Remote Control’ section of our VEX Cortex Video Trainer using ROBOTC (link below). Also, take a look through the ‘Remote Control’ sample programs which can be used as a base template for remote control programming.
Setting up a VEXNet connection:http://help.robotc.net/WebHelpVEX/index.htm#Topics/Getting%20Started/Getting%20Started%20-%20Cortex%20VEXNet.htm%3FTocPath%3DGetting%2520Started%2520-%2520Physical%2520Robots|_____3
VEX Cortex Video Trainer using ROBOTC: http://www.education.rec.ri.cmu.edu/products/teaching_robotc_cortex/index.html