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Getting Started with FRC·Lesson 19 of 28

The Connection Chain: When the Driver Station Won't Connect

A systematic walk through the communication, robot code, and joystick indicators when your robot won't enable.

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Before any motor moves, three green boxes must light up in the FRC Driver Station: Communications, Robot Code, and Joysticks. Debug them left to right — each depends on the one before it.

Communications red. The DS cannot reach the roboRIO. Causes, in order of likelihood: (1) Wrong team number set in the DS Setup tab — it must match your roboRIO's configured number exactly. (2) Radio not powered or not configured — the radio needs power and a flashed configuration for your team number. (3) Wrong network — you are on the wrong Wi-Fi/USB. Quick test: open a terminal and ping roborio-TEAM-frc.local (replace TEAM with your number). No reply means it is a network/hardware problem, not a code problem. Tethering over USB to the roboRIO bypasses the radio entirely and is the fastest way to isolate radio issues.

Communications green, Robot Code red. This is Warning 44003: 'No robot code is currently running' — the DS reached the roboRIO but no program is running. Causes: (1) No code was ever deployed, or the last deploy failed — redeploy and watch the RioLog for 'Robot program starting'. (2) The code crashed on startup — scroll the RioLog/console for a Java stack trace; an uncaught exception in your constructor or robotInit kills the program instantly. (3) A known roboRIO 2.0 quirk where the program does not start despite being deployed — reboot the roboRIO. (4) Someone held the roboRIO User button for several seconds, or something on the robot is physically pressing it — check that nothing rests against the button.

Robot Code green, Joysticks red. The roboRIO is running but the DS sees no controller. Plug the controller into the DS laptop (not the robot), and in the DS USB tab drag it to the slot your code expects (port 0 by default). A controller that worked yesterday but not today is usually in the wrong slot after a reboot.

The disciplined workflow: never jump straight to 'my code is broken'. Verify Communications, then Robot Code, then Joysticks. The Driver Station's Diagnostics tab shows roboRIO/radio link state and round-trip time; rising or erratic trip time points to a flaky radio or Wi-Fi interference, which on a competition field you address by re-seating Ethernet and checking the radio's power. Most 'it won't drive' panics are solved in this checklist within two minutes.

Key takeaways

  • Debug the three DS indicators left-to-right: Communications, then Robot Code, then Joysticks
  • 44003 'No robot code' means the roboRIO is reachable but no program runs — redeploy, read the RioLog stack trace, or reboot the roboRIO
  • Tether over USB to isolate radio problems; use ping roborio-TEAM-frc.local to separate network issues from code issues

Go deeper

Lesson quiz

Required

Answer all 3 questions correctly to complete this lesson.

1.On the FRC Driver Station, the 'Communications' indicator is green but the 'Robot Code' indicator is red. What does this tell you?

2.When the Driver Station won't connect over the wireless radio, what is the recommended way to isolate whether the problem is the radio versus the roboRIO/code?

3.On a competition robot using the standard FRC IP scheme, what address does the roboRIO normally obtain via DHCP from the robot radio?

Answer every question to submit.