Cortex "red lights of death"

While practicing with our robot tonight, we encountered a bizarre issue with our cortex: while letting the robot sit (power on) and stationary, our controller disconnected, ports 1 and 10 started delivering power, and our solenoids began to rapidly fire on and off.

All 3 of our cortex lights turned red, with the robot light flashing a few times per second.

We guessed that it was a firmware issue (somehow our firmware corrupted in the middle of practicing?), so we pressed the reset button on the cortex and manually uploaded new firmware with ROBOTC. That failed several times, until without reason, our cortex began to function again.

After about 10 more minutes of practicing, the same issue happened. This time uploading firmware didn’t fix the issue. There doesn’t seem to be much info on this kind of situation.

For reference, yesterday afternoon we used the VEXnet Firmware Upgrade Utility and made the switch to VEXnet 2.0 keys with the World’s firmware update. Due to random connection drops, we switched back to VEXnet 1.0 keys yesterday and until the random cortex failure in the middle of practicing it has been working fine.

Can anyone help with this? (P.S. we are using a different cortex for Worlds)

Sounds like a short or something. Did you try switching batteries?

We did we noticed that the light pattern was the same when the cortex was plugged via usb into a laptop with no batteries connected.

I don’t think we have encountered this exact issue before, but it sounds similar, last year due to static build up on the field, the IMEs would build up static and shock the brain, making it continue to do whatever function it was doing at the moment, however there weren’t any weird light sequences that went with it so it could or could not be related.

this is the first step i would take to solving the issue, but the best solution I can suggest is listed under the flow start>does the cortex turn on> yes> Is the robot LED on the cortex consistently red?> yes> Is the robot LED blinking> yes> Fast or slow blink> slow> single or double blink> Double> solution. I’m not sure whether these are the correct lights that you are using but the it does seem that considering what was being done on the robot most recently is most related to this fix. Have you updated to the very recent firmware, and have the keys been updated, and has the joystick been updated too?

Unfortunately new firmware has not fixed the issue. In my original post I forgot to mention that we could successfully upload the master firmware only when in bootloader mode, but as soon as it finishes the lights go back to the red pattern described previously, and RobotC Can no longer communicate with it.

have you narrowed it down anymore to a certain one of the problems yet?
Backup battery

Which version of ROBOTC are you using?
Which firmware versions are you uploading?

Couple of things to try.

  1. Use the VEXnet upgrade utility to update to the latest firmware (V4.22) rather than using ROBOTC. After that use ROBOTC to only update the ROBOTC firmware.

  2. Do a software inspection from ROBOTC (robot menu->advanced->software inspection), does that work, post the results here.

We are using ROBOTC 3.62. After putting the cortex into bootloader mode and upgrading with the VEXnet upgrade utility to V4.22, the cortex returns back to its red light state (solid red on VEXnet and GAME, but flashing red on ROBOT).

The software inspection (when the cortex is in bootloader mode since that is the only way it communicates with the computer) yields this:

Communications Link:               USB HID Cable Connection to Cortex

Standard Firmware File Names:
VEXNET Joystick:                   .\Firmware\JOY_V3_23.BIN
VEX Cortex Master CPU Firmware:    .\Firmware\CORTEX_V3_23.BIN
VEX Cortex CPU Firmware:           .\Firmware\VEX_Cortex_0968.hex

VEXnet Joystick Integrity:
This device is not connected

Cortex Master CPU Integrity:
Bootload Firmware Version:         8.00                    Up to Date
This device is in boot loader mode. Configuration data not available

What is the likelihood that the cortex experienced a short due to the humidity of our practice space? It’s probably not coincidental that this occurred while we were practicing in an open garage, shortly after a thunderstorm. The air was pretty humid.

So the cortex is stuck in bootload mode. Slow red double blink on the robot LED means the cortex lost it’s id code (factory programmed so they are all unique). If that’s the case then call vex support next week when they are back. That’s a rare case but can happen and you need their input on that. You could make sure the config button is not stuck, use a paper clip and make sure it clicks on and off when you gently push it.

Not impossible but unlikely unless it actually got wet.

Not sure what to tell you other than contact vex support at this point, it probably is recoverable but without actually having it in my hands it’s hard to tell. If you will be at worlds then I’m sure they will be able to help there as well, or find me tomorrow afternoon at inspection or with the ROBOTC team.

Thanks for your help! We are currently using a different cortex, so it is not an issue at the moment. We will be at Worlds on Thursday and our team will find you when you seem available to have you look at it.

If you have one you could try a new cortex if you haven’t already.

Alright so we are doing drive practice and then all of a sudden the robot goes dead three solid red lights on the cortex and a blinking vexnet light on controller any suggestions

Try upgrading your Vex Controller, Brain, VexNet itself etc.

If not make sure your battery’s aren’t stripped or anything.

When my team experiences this it generally means to upgrade firmware.