WT9901C2-SN2 Beginner's Guide

1. How to Flash AT Firmware

1.1 Preparation

The following hardware and software are required for flashing firmware on the WT9901C2-SN2 development board:

• Hardware:
  • WT9901C2-SN2 development board x 1
  • TypeC USB cable x 1
  • Personal computer (operating system supports Windows 7 [64-bit], Windows 10, Windows 11) x 1
• Software:
  • AT Firmware x 1
  • Flashing Tool x 1

1.2 Entry Page

Open the flashing tool, double-click the .exe file to enter the tool's entry interface, and switch ChipType to esp32c2 as shown below:

Flashing Tool Entry Page

Click OK to enter the main flashing page.

1.3 Select AT Firmware for Flashing

Connect the microcontroller to the computer using a TypeC USB cable and identify its COM port.

Extract the downloaded AT Firmware and configure the flashing tool as shown below:

Flashing AT Firmware

Click START to begin flashing.

Open a serial terminal tool and configure the settings as follows:

• Baud Rate: 115200
• Data Bits: 8
• Parity: None
• Stop Bits: 1
• Flow Control: None
• Enter the "AT+GMR" command with line ending (CRLF)
  If the result appears as shown below, it indicates success:

AT Response After Successful Flashing

2. How to Set Up ESP-IDF and Compile/Flash the Hello World Example

1. Set up the environment following the Espressif Official Tutorial

2. Copy the examples/get-started/hello_world/ folder to your current directory.

3. Activate the esp-idf environment

Done! You can now compile ESP-IDF projects.
Go to the project directory and run:

  idf.py build

4. Switch to the esp32c2 target

idf.py set-target esp32c2

5. Compile the hello world project

idf.py build

6. Flash the hello world project

idf.py flash -p <PORT>

7. Open the serial monitor for hello world

idf.py monitor -p <PORT>

3. How to Use WT9901C2-SN2 as a Flasher for Other Development Boards

Short the EN and GND pins using a jumper cap. The development board can then be used as a flasher or serial monitor. As shown below:

Development Board Flasher Wiring