• UART
  • Beginner
  • 3 min
  • Serial CLI

Recipe · Beginner · UART

How to bridge a UART console

After identifying the UART pins and baud rate, the next step is often an interactive console. Bridge mode turns Bit Pirate into a passthrough between your terminal and the target UART.

UART signal lines between two connected devices.
Use passive reads first, then bridge once TX is safe.

Wiring View

BP TXBP RXRXBP TXGNDBP GND
Generated from the wiring summary: to BP.
Step 1

Commands

Run the commands below after selecting the right Bit Pirate mode and confirming the wiring.

Result

What success looks like

You can see the target output and type into the console. If you only see output but input does nothing, swap RX/TX or verify the target accepts console input.

Troubleshooting

  • RX and TX are not crossed.
  • Wrong baud rate or parity.
  • Target console is read-only or disabled.
  • ESP32 TX voltage is not safe for the target.
  • Bridge mode does not accept a terminal escape command: terminal input is forwarded to the target. Press any physical button on the ESP32 to return to Bit Pirate.

Next steps

  • Use write AT for a one-shot command when a full bridge is not needed.
  • Use swap if RX/TX are reversed in the firmware config.
  • Use xmodem only when the target bootloader explicitly supports it.

UART bridge FAQ

When is bridge mode better than write and read?

Use bridge mode for an interactive UART console, bootloader menu or shell where you need to type and immediately see replies. Keep write and read for short probes when you want to stay inside the Bit Pirate command prompt.

Why start with target TX before full bridge?

Listening to target TX first is passive and usually enough to learn baud rate, boot text and prompt style. It gives context before you actively drive the target RX line.

Why is the console text readable at first, then broken in bridge mode?

The usual causes are a baud rate mismatch, parity/stop-bit mismatch, reset-time autobaud behavior, or RX/TX wiring that only works in one direction. Re-run passive read, confirm the UART settings, then enter bridge again.

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