Getting Started with the VEX Cortex

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Tutorials → Getting Started with the VEX Cortex

Configuring the VEX Cortex for a WIRED connection using USB

This is a guide for setting up the VEX Cortex using the USB A-to-A cable. These steps are required the first time you use your computer to program a specific VEX Cortex, or after you've upated ROBOTC to the latest verstion. Once you've successfully completed these steps you can download your own programs without revisiting them. Note: Administrative privileges are required for some of these steps.

Note: Driver Installation

ROBOTC 3.05 and later automatically installs the necessary drivers for the VEX Cortex, VEXnet Joysticks, and USB-to-Serial Programming cable. If you need to download the drivers for troubleshooting purposes, you can still find them at
The drivers for the CORTEX Microcontroller and VEXnet Joysticks are included in the ROBOTC 3.0 installers. If, for any reason, you need to download them separately, here are the downloads:
Download Network Driver (in addition to required driver) if ROBOTC will run from a network:

Step 1: Connect the Cortex to your PC

Connect the VEX Cortex directly to a USB port on your computer using the USB A-to-A cable. Allow a few seconds for Windows to recognize the device.


Connect a 7.2V Robot battery to the Cortex and move the POWER switch to the ON position. Optionally, you can connect two motors to MOTOR Ports 2 and 3 for testing a sample program later in the sequence. You can connect 3-wire motors directly, or the newer 2-wire motors using Motor Controller 29 cables.

Vex2-getting-started-battery motors.JPG
Note: Technically, the battery is not necessary for downloading Master CPU Firmware and ROBOTC Firmware, but it has helped in cases where the USB ports on the computer provide too little power to facilitate a reliable connection to the Cortex.

Step 2: Platform Type and Communication Port

Specify that you are using the Cortex and how it is connected to your computer in ROBOTC. Go to Robot > Platform Type > Innovation First (IFI) and select "VEX 2.0 Cortex" or "Natural Language (VEX Cortex)".

Note: You should choose "VEX 2.0 Cortex" if you plan on programming using the standard ROBOTC language. Choose "Natural Language (VEX Cortex)" if you want to take advantage of the Natural Language commands in ROBOTC.

Then go to View and choose Select Communication Port.

Comm port.png

The Select Communications Port for Platforms window will appear. From the Communications Port drop down list, you should see "Automatic Selection" and one of two additional options:

If your VEX Cortex is in "bootload mode" or running an older (2.x) version of the Master CPU Firmware, it will appear as a "USB Wired Cable" option in the list.
Comm port select.png

If your VEX Cortex is running a newer (3.x) version of the Master CPU Firmware, it will appear as a "Vex Robotics Comm Port" in the list.

Make sure that "Automatic Selection" or one of the two legitimate options is selected. If you ever plan on programming your robot wirelessly over VEXnet, choosing "Automatic Selection" is recommended. Press OK to save your choice.

Important: If the "USB Wired Cable" or "Vex Robotics Comm Port" options do not appear in the drop down menu when a VEX Cortex is connected, this may indicate that Windows has not recognized the device or access to it is blocked. Ensure that the VEX Cortex Device Driver was successfully installed with Administrative Privileges, disconnect and reconnect your Cortex from the computer, and press "Refresh List" to force ROBOTC to repopulate the list.

Step 3: Updating VEX Cortex Firmware