Known Issues

This article details known issues (and workarounds) for FIRST® Control System Software.

Open Issues

I2C numbering backwards

The I2C numbering in WPILib is backwards from what the labels are on SystemCore. This will be fixed in Alpha 2 and later releases.

DutyCycle.getOutput crashes

Attempting to call DutyCycle.getOutput() or DutyCycleEncoder.get() without calling setAssumedFrequency() will crash. This is because currently the HW does not report frequency, which doesn’t allow us to compute a percentage output. This also means getFrequency() also will fail.

Use DutyCycle.getHighTime() or DutyCycleEncoder.setAssumedFrequency(), and use the value specified in the datasheet of the sensor to compute a percentage output.

SystemCore won’t get 10.TE.AM.2 address from Radio.

Due to the change in Hostname, the radio will not hand out .2 to SystemCore. Use the IP address displayed on the SystemCore screen if you need to know the IP address.

Generally, everything should work in this configuration. But if you run into issues where the DS cannot connect (And you’re sure the team number is set, it’s required to connect the DS and can be verified on the screen), you can manually type the IP address into the team number selector in the DS.

Unable to deploy on macOS when multiple VS Code versions are installed

Issue: On macOS, having multiple installed copies of Visual Studio Code can cause deploy operations to fail because of macOS local network privacy

Workaround: Open Settings -> Privacy and Security -> Local Network Access and ensure that all VS Code versions are allowed Local Network Access.

If that doesn’t work, you can run the following commands in a terminal and then reboot. This allows any program to access the robot’s network.

sudo defaults write com.apple.network.local-network AllowedEthernetLocalNetworkAddresses -array "10.0.0.0/8"
sudo defaults write com.apple.network.local-network AllowedWiFiLocalNetworkAddresses -array "10.0.0.0/8"

Warning

This also allows any program to access any network with the address in the range of 10.x.x.x, which may be undesirable if you connect to other networks in that range beside’s the robot’s network. If you only access a robot with a single team number, you can substitute 10.TE.AM.0/24` (TE.AM IP Notation). If you only access the robot’s network over eithernet or WiFi, you can only run the appropriate command.

Driver Station randomly disabled

Issue: The Driver Station contains tighter safety mechanisms introduced in 2024 to protect against control issues. Some teams have seen this cause the robot to disable.

Workaround: There are multiple potential causes for tripping the safety mechanisms.

Note

The new safety mechanisms will not disable the robot when connected to the FMS.

The Driver Station software has new tools for control packet delays that could cause this. The control system team requests that teams that experience this issue post screenshots of the Driver Station Timing window to https://github.com/wpilibsuite/allwpilib/issues/6174

Some teams have seen this happen only when the robot is operated wirelessly, but not when operated via USB or ethernet tether. Some potential mitigations:

  1. Try relocating the robot radio to a better location (high in the robot and away from motors or large amounts of metal). Follow the manufacturer’s recommended mounting

  2. Measure your robot’s bandwidth and ensure you have margin under the 7 Mbps bandwidth limit

  3. See if the Wi-Fi environment is congested using a tool like WiFi Analyzer.

  4. Utilize the recommended 2 radio setup. 1. Ensure the DS Radio is mounted high, away from interference and humans walking between the DS radio and the robot. 2. Use ethernet to connect the DS computer to the DS Radio

  5. Update the Wi-Fi drivers for the DS computer.

Some teams have seen this happen due to software that is running on the driver station (such as Autodesk updater or Discord). Some potential mitigations:

  1. Reboot the driver station computer

  2. Close software that is running in the background

  3. Follow the Driver Station Best Practices

While rare, this can be caused by robot code that oversaturates the roboRIO processor or network connection. If all other troubleshooting steps fail, you can try running with one of the WPILib example programs to see if the problem still occurs.

If you identify software that interferes with driver station, please post it to https://github.com/wpilibsuite/allwpilib/issues/6174

Driver Station Reports Less Free RAM then is Available

Issue: The Driver Station diagnostic screen reports free RAM that is misleadingly low. This is due to Linux’s use of memory caches. Linux will cache data in memory, but then relinquish when the robot programs requests more memory. The Driver Station only reports memory that isn’t used by caches.

Workaround: The true memory available to the robot program is available in the file /proc/meminfo. Use ssh to connect to the robot, and run cat /proc/meminfo.

MemTotal:         250152 kB
MemFree:           46484 kB
MemAvailable:     126956 kB

The proper value to look is as MemAvailable, rather then MemFree (which is what the driver station is reporting).

Simulation crashes on Mac after updating WPILib

Issue: On macOS, after updating the project to use a newer version of WPILib, running simulation immediately crashes without the GUI appearing.

Workaround: In VS Code, run WPILib | Run a command in Gradle, clean. Alternatively, run ./gradlew clean in the terminal or delete the build directory.

Invalid build due to missing GradleRIO

Issue: Rarely, a user’s Gradle cache will get broken and they will get shown errors similar to the following:

Could not apply requested plugin [id: ‘edu.wpi.first.GradleRIO’, version: ‘2020.3.2’] as it does not provide a plugin with id ‘edu.wpi.first.GradleRIO’

Workaround:

Delete your Gradle cache located under ~$USER_HOME/.gradle. Windows machines may need to enable the ability to view hidden files. This issue has only shown up on Windows so far. Please report this issue if you get it on an alternative OS.

Chinese characters in Driver Station Log

Issue: Rarely, the driver station log will show Chinese characters instead of the English text. This appears to only happen when Windows is set to a language other then English.

Chinese character appearing in the Driver Station log window.

Workaround: There are two known workarounds:

  1. Copy and paste the Chinese characters into notepad, and the English text will be shown.

  2. Temporarily change the Windows language to English.

C++ Intellisense - Files Open on Launch Don’t Work Properly

Issue: In C++, files open when VS Code launches will have issues with Intellisense showing suggestions from all options from a compilation unit and not just the appropriate ones or not finding header files. This is a bug in VS Code.

Workaround:

  1. Close all files in VS Code, but leave VS Code open

  2. Delete c_cpp_properties.json file in the .vscode folder, if it exists

  3. Run the “Refresh C++ Intellisense” command in VS Code.

  4. In the bottom right you should see something that looks like a platform (linuxathena or windowsx86-64 etc). If it’s not linuxathena click it and set it to linuxathena (release)

  5. Wait ~1 min

  6. Open the main cpp file (not a header file). Intellisense should now be working

Issues with WPILib Dashboards and Simulation on Windows N Editions

Issue: WPILib code using CSCore (dashboards and simulated robot code) will have issues on Education N editions of Windows.

  • Shuffleboard will run, but not load cameras

  • Smartdashbard will crash on start-up

  • Robot Simulation will crash on start-up

Solution: Install the Media Feature Pack