Hardware Connection


This document introduces what hardware you need to prepare and how to connect them in order to download AT firmware, send AT commands, and receive AT responses.

The commands supported by each series of AT firmware vary, and its compatibility with modules or chips also differs. For more information, refer to ESP-AT Firmware Differences.

If you don’t want to use the default AT pin, you can refer to the How to Set AT Port Pins document to change the pin.

What You Need

List of Components Required for ESP-AT Testing



ESP32-C6 board

Slave MCU.

USB cable (ESP32-C6 board to PC)

Download/Log output connection.


Act as Host MCU. Download firmware to Slave MCU.

USB cable (PC to serial port converter)

AT command/response connection.

USB to serial port converter

Convert between USB signals and TTL signals.

Jumper wires (serial port converter to ESP32-C6 board)

AT command/response connection.

Connection of Components for ESP-AT Testing

Connection of Components for ESP-AT Testing


  • In the above picture, four jump wires are used to connect the ESP32-C6 board and USB to serial converter. If you do not use hardware flow control, two wires connecting TX/RX and a simpler converter will be enough.

ESP32C6-4MB Series

ESP32C6-4MB series refer to the module or board that has a built-in ESP32-C6 chip with a 4 MB flash, such as ESP32C6-MINI series device and ESP32C6-WROOM series device.

ESP32C6-4MB AT uses two UART ports: UART0 is used to download firmware and log output; UART1 is used to send AT commands and receive AT responses. Both UART0 and UART1 use 115200 baud rate for communication by default.

ESP32C6-4MB Series Hardware Connection Pinout

Function of Connection

ESP32C6-4MB Board or Module Pins

Other Device Pins

Download/Log output 1

  • GPIO17 (RX)

  • GPIO16 (TX)

  • TX

  • RX

AT command/response 2

  • GPIO6 (RX)

  • GPIO7 (TX)

  • GPIO5 (CTS)

  • GPIO4 (RTS)

USB to serial converter
  • TX

  • RX

  • RTS

  • CTS

Note 1: Connection between individual pins of the ESP32C6-4MB board and the PC is already established internally on the ESP32C6-4MB board. You only need to provide USB cable between the board and PC.

Note 2: Connection between CTS/RTS is optional, depending on whether you want to use hardware flow control.

ESP32C6-4MB Series Hardware Connection

ESP32C6-4MB Series Hardware Connection

If you want to connect your device directly with ESP32C6-4MB module rather than the ESP32C6-4MB board that integrates it, please refer to the corresponding module datasheet for more details.