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There have been reports of the VEX Cortex locking up when using the new Integrated Motor Encoders. The root cause appears to be an unhandled exception that is generated when the I2C communication link between the Cortex and encoders is compromised. To prevent the Cortex from locking up, we’ve put together a new ROBOTC Firmware file that handles the exception. The differences between this new firmware and the version included in ROBOTC 3.08 only apply to the new Integrated Motor Encoders, so users who aren’t taking advantage of them should continue using the firmware included in ROBOTC 3.08. VEX Robotics Competition teams that are using the encoders are encouraged to load the new firmware, and to take extra steps (zip ties, ect) securing the 4-pin I2C wires, to help prevent them from coming loose in the first place.

The new ROBOTC firmware, “VEX_Cortex_0912A” can be downloaded here. Once the file is downloaded, you will need to extract the .hex file from it.

To transfer the firmware to your Cortex:

1. Open ROBOTC
2. Go to Window > Menu Level > Expert
3. Make sure the Cortex is connected to the PC over USB or VEXnet
4. Go to Robot > Download Firmware > ROBOTC Firmware > Choose File…
5. When the File Selection window appears, navigate to the “VEX_Cortex_0912A.hex” file you extracted and select it
6. A Download Progress window will appear in ROBOTC and begin the download
7. When the Download Progress window closes, the Firmware download is complete

More information on the problem can be found in this post on the VEX Forums.

Thanks to everyone for submitting your testing results, and for your patience as we work out the issues. A special thanks goes out to VEX Forum user, jpearman.

VEX Robotics has released the following information on their website:

The VEX Robotics technical support team has identified an issue that some competition teams are experiencing in which the Cortex Microcontroller is unable to resume VEXnet link after a Microcontroller reset.

To help eliminate this issue at the VEX Robotics World Championship we are releasing a special version of the VEX Firmware, specifically for World Championship teams (3.21_Worlds). This firmware version modifies the Cortex re-initialization to help the VEXnet link reconnect in the event of a reset (i.e. caused by VEXnet Key “jostling”, power interruption, battery brownout, or static).

We know that competition teams dislike updating firmware so close to an event, so we are publishing this update in the hopes that teams will have a chance to test it “at home” before coming to VEX Worlds. If you’re comfortable with the new version, we strongly urge you to use it at the World Championship to help prevent potential problems related to a Cortex reset.

This firmware only updates a “back end” relinking protocol and it does not affect anything related to robot performance — you don’t need to tweak your autonomous mode, or anything like that.

Visit the VEX Forum thread on this firmware release for more discussions and to post any questions or concerns.

Download the 3.21_Worlds Firmware Update.

A few weeks ago I came to the VEX Regionals over at Monroe, Michigan which was held at  Monroe High School. This was their first year hosting the VEX competition, and Steve Ketron did a nice job organizing the event.

There were about two dozen teams, and the robots that were built by the teams were phenomenal.

I’ve been fortunate enough to go to several VEX competitions over the years, and this one had a very friendly and relaxed atmosphere. I’d chalk that up to the friendly teams surrounding Monroe that came, and also Steve’s planning for the competition.

Photos

I took several hundred photos AND video for the event. I will post the video as soon as I can get all of them onto youtube.

Note: If you want a photo removed, I completely understand! Just comment on this post letting me know which photo to remove and I will remove it immediately. Your comment will not show up below so it will be anonymous.