ROBOTC for VEX Robotics 4.08 now available

The ROBOTC Development Team is excited to announce the availability of ROBOTC for VEX Robotics 4.08 – an update for the VEX Cortex and VEX IQ platforms.

This new version supports the latest firmware versions provided by VEX Robotics (4.20 for VEX Cortex / 1.09 for VEX IQ) and all of the new features supported by the new firmware updates. Some of these new improvements include:

  • Support for the VEXnet 2.0 (white) Radios for the VEX Cortex
  • Bug Fixes for the VEX IQ system to prevent “I2C Errors”
  • Speed enhancements for VEX IQ for better performance of motors and sensor
  • New VEX IQ commands for Gyro sensors

This new version of ROBOTC also supports the VEX IQ “Graphical Natural Language” feature. This new interface allows users to program robots from inside ROBOTC with easy-to-use graphical blocks that can be drag-and-dropped to form a program. Each block represents an individual command from the “text-based” ROBOTC and Natural Language. The new click and drag interface along with the simplified commands of Natural Language allows any robotics user to get up and running with programming their robots as soon as possible. As of today, the Graphical Natural Language commands work with the VEX IQ system, but we’re actively developing support for ALL ROBOTC supported platforms!

Before you can use ROBOTC for VEX Robotics 4.08, you will need to ensure that your VEX devices are up to date. The instructions to update your hardware will be different depending on what hardware setup you may have…

VEX IQ Users

  • Run the “VEX IQ Firmware Update Utility” and update your VEX IQ brain to firmware version 1.09. You will also have to install the latest ROBOTC firmware from inside of ROBOTC.

VEX Cortex Users (with Black VEXnet 1.0 Keys)

  • You will need to update your VEX Cortex and VEX Game Controllers with version 4.20 from inside of ROBOTC. After updating your master firmware, you will also have to install the latest ROBOTC firmware as well.

VEX Cortex Users (with White VEXnet 2.0 Keys)

  • The new VEXnet 2.0 keys have a specific “radio firmware” that you will need to upgrade to enable “Download and Debugging” support. You can find this utility here.
  • Download the “VEXnet Key 2.0 Firmware Upgrade Utility” and insert your VEXnet 2.0 key to any free USB port on your computer. Follow the instructions on the utility to update each key individually. All VEXnet 2.0 keys must be running the same version in order to function properly.
  • After updating your VEXnet 2.0 keys, you will need to update your VEX Cortex and VEX Game Controllers with version 4.20 from inside of ROBOTC. After updating your master firmware, you will also have to install the latest ROBOTC firmware as well.
  • Note that this new firmware version will support download and debugging with both VEXnet 1.0 (black) and VEXnet 2.0 (white) keys.

For more information on ROBOTC for VEX Robotics 4.08, please see this blog post. You can download the latest version of ROBOTC for VEX Robotics here.

This sounds great! Just a few questions:

  1. If I were to upgrade all of my VEXnet 2.0 keys to their new v1.36 firmware, but NOT upgrade the Cortex to 4.2, would wireless downloading/debugging work? (If not, would everything else still work fine, or am I forced to upgrade the Cortex to 4.2 in order to simply use my upgraded 2.0 keys?) (I suppose this is kind of an IFI question.)

  2. I know this is strictly a question for IFI, but does the new version of the VEXnet Firmware Upgrade Utility have the 4.2 firmware, even though it still says 4.1? (I am assuming yes, since it was updated on the same day that the 2.0 key upgrader was.)

  3. If I do not install RobotC 4.08, can I still use RobotC 3.62 wireless downloading/debugging with the new 2.0 keys, provided that I upgrade everything else?


Having some issues with the debugger… Kinda sorta works for a while… but recovery from drops is not as good.

I downloaded all the firmware as instructed. I then downloaded the robot’s program. So far so good.

This program has a bit of global variables and debug streaming. 4 motors chained on the I2c too. Not sure if that makes a difference. I only tried driver control as I was in the kitchen…

  1. The failure reading brick status and failure reading sensor variables started appearing nearly right away. Grrr. I guess it is not wi-fi interference after all. Upon robot re-connect the debugger does not always come back on line which is not good. The robot moves but the debug stream is not updating.

  2. Then upon a download attempt it now says the firmware is our of date and needs updating to 4.20. However a power recycle it downloads fine.

  3. Hitting stop made a “get failure reading flash file” error once. Not sure what that is.

Then I tried playing with a competition switch since the frequencies are supposed to be different. When does the competition frequency start? If you start in debugger mode does it switch over once the competition switch gets plugged in or does it go on competition frequencies only upon start up with the competition switch plugged in?

I also had a case but can’t remember what caused it where the joystick lights were all green but the cortex lights were not. I will keep an eye out for those conditions.

FYI - Using Windows 7 with robot c 4.08 run as administrator

The competition switch does not cause a change of frequency, the field control system does.

I sent you a PM, no one else needs to know implementation details yet.

Unofficial answers.

You need to do the update of both the keys and cortex/joystick.

The version of the VEXnet utility does not match the firmware version, it never really has, for example, V3.2.8 utility contained V3.23 firmware. I wish they matched, it would make life easier. The posted utility V4.1.0 contains firmware V4.20.

There will be a new version, V3.63, that supports the debug/download modes. It will “almost” work in V3.62 but at best would be unreliable. V3.63 “may” be out next week. V4.08 and V3.63 can be installed on the same PC, obviously V4.08 is a paid upgrade from V3.xx.

Can we have v4 installed at the same time as v3? We have a lot of teams that are running Cortex and PIC. Some of our demo kits ate PIC and some Cortex.

Yes - you’ll be able to have ROBOTC 3.X installed at the same time as ROBOTC 4.x.

We’re hoping to have 3.63 which has support for the VEXnet 2.0 radios released in the next few days.