• UART
  • Beginner
  • 3 min
  • Serial CLI

Recipe · Beginner · UART

How to use the UART AT shell

Use UART mode at helper to send guided AT commands to modems and serial modules.

UART signal lines between two connected devices.
Start with read-only checks, then move to write, replay or automation only when the setup is understood.
Step 1

Commands

Use the shortest command path that matches the documented firmware workflow. When a mode needs setup, follow the prompts shown on first entry.

Result

What it means

The command path is working when the target responds and the firmware prints the expected menu, status or captured data.

Troubleshooting

  • Re-enter the mode setup when pins or peripherals are not already initialized.
  • Check common ground and target voltage before blaming software.
  • Prefer Serial CLI for long captures or high-volume output.
  • Repeat the read or capture to confirm stability.

Next steps

  • Save the output in your project notes.
  • Compare the result with the full wiki page for mode-specific details.
  • Create a shorter alias if you repeat this workflow often.

UART AT shell FAQ

Why use the AT shell instead of plain write?

The AT helper is better when commands share a template and line ending. Plain write is fine for one-off strings, but the shell reduces mistakes during repeated modem checks.

What does the AT shell add over UART write?

The AT shell gives a modem-oriented loop for sending commands and reading replies without rebuilding each command manually. It is more convenient once the UART link is known.

Are all AT commands universal?

No. AT is a command style, not one standard command set. Cellular modems, Wi-Fi modules, GPS modules and Bluetooth modules can all use different command families.

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