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UART Access Checklist

Use this checklist when an STM32-based end node cannot be accessed through UART or does not respond to AT commands.

1. Check the UART Connection​

  • Use a USB-to-TTL converter. An RS232 converter will not work for TTL UART pins.
  • Confirm the converter's TXD and RXD pins are connected according to the device user manual.
  • Make sure GND is connected between the USB-to-TTL converter and the device.
  • Power the device correctly before opening the serial console.

2. Check Serial Port Settings​

Use the following serial settings:

SettingValue
Baud rate9600
Data bits8
Stop bits1
ParityNone
Flow controlNone

3. Send AT Commands Correctly​

  • Check whether the serial console shows boot or debug output from the device.
  • Add both Enter and New Line after the AT command before pressing send.
  • Some serial utilities do not add a new line by default, so the device may not execute the command.

Serial utility new line setting

Example of adding a new line in serial software.

4. If the Issue Still Exists​

Send the following information to support@dragino.com:

  • A screenshot of the serial utility baud-rate settings.
  • A screenshot of the serial console output.
  • A clear photo showing how the USB-to-TTL adapter is connected to the device.