VSD32-S3 — Flashing AT Firmware over UART

This short guide shows you how to download the AT firmware image and flash it onto a VSD32-S3 board (ESP32-C3 Wi-Fi/BLE module) using Espressif’s Flash Download Tool.

Before you start
Make sure the hardware is wired exactly as shown in the table below.

VSD32-S3 signal / pin	Connect to	Notes
WiFi_P_Tx	FTDI232 Rx	UART TX from VSD32-S3 → FTDI RX
WiFi_P_Rx	FTDI232 Tx	UART RX on VSD32-S3 ← FTDI TX
GND	FTDI232 GND	Common ground reference
WiFi_P_BOOT	VSD32-S3 GND	Keep low to boot ESP32-C3 into normal flash-run mode

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1. Download the required files

File	Purpose	Link
factory_MINI-1.bin	AT firmware image	https://github.com/VSDSquadron/VSDSquadron_Ultra/blob/main/factory_MINI-1.bin
flash_download_tool.zip	Espressif Flash Download Tool (Windows)	https://github.com/VSDSquadron/VSDSquadron_Ultra/blob/main/flash_download_tool.zip

Unzip flash_download_tool.zip somewhere convenient (e.g. C:\esp\flash_tool\).

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2. Flash the firmware

1. Open flash_download_tool_x.x.x.exe.

2. In the first dialog choose the ChipType → ESP32-C3.

3. Choose WorkMode → Develop.

4. Choose LoadMode → UART. (see below image)

5. Click OK to enter the main window.

   

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3. Verify the connection with Chip Debug Tool

After you click OK in step 5, a new window titled CHIP DEBUG TOOL V3.9.8 pops up.

1. Click the chipInfoDump tab.
2. In the port drop-down, choose the COM port that the VSD32-S3 is attached to
   (if two ports appear, unplug the board to see which one disappears, then re-select it).
3. Leave baudrate at 115200.
4. Press Chip Info.

If everything is wired correctly, the log area should show output similar to:

Troubleshooting:
• If “chip sync …” never completes, swap TX/RX lines or re-check that WiFi_P_BOOT is firmly tied low.
• Make sure the COM port isn’t already open in another terminal session.

Continue with step 4 to select the firmware binary and start flashing.

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4. Load the firmware in SPIDownload tab and flash

1. Switch back to the SPIDownload tab.

2. In the first line of the file table click … and browse to the firmware image you downloaded earlier:
   factory_MINI-1.bin

3. Address → 0x0 (leave the default value).

4. Tick the checkbox for that row so the file is enabled.

5. Leave DoNotChgBin checked (keeps the factory-image SPI flash settings).

6. Confirm the default SPI settings:

   Setting	Value
   SPI SPEED	40 MHz
   SPI MODE	DIO
   BAUD	115 200 bps (or lower if you see sync errors)
   COM	Port you selected in the previous step

7. Click START.
   The log will show “Connecting…”, then a progress bar; when finished you should see “FINISH” in green.

Hint: If flashing stalls at “Sync…”, press RESET on the VSD32-S3 while keeping WiFi_P_BOOT low, then click START again.

5. Monitor flashing progress

Click START and the tool immediately begins writing the image to flash:

• A green Download status panel lights up.
• The red bar at the very bottom fills from left-to-right, indicating progress (see screenshot below).

Do not disconnect power or the USB cable until the bar reaches 100 % and the status changes to “FINISH”.

When completed you should see the below image at the bottom of FLASH DOWNLOAD TOOL:

9. Upload a quick Soft-AP test sketch from Arduino IDE

You can now unplug the FTDI232 adapter; only the USB-C cable between your PC and VSD32-S3 is required.

1. Open Arduino IDE (v2.x recommended).
2. Ensure the ESP32 Arduino core is installed, then select
   Board → ESP32C3 Dev Module and the Port that appears when the board is plugged in.
3. Grab the test sketch: vsd32s3_softap.ino.
4. Open the sketch and click Upload.
5. When the upload completes, open Serial Monitor at 115200 baud.

What the sketch does

// vsd32s3_softap.ino
// Bring up ESP32-C3 as a Wi-Fi Access Point
// SSID = "VSD32-S3"
// PASS = "vsd12345"

The sketch sends AT commands to the ESP32-C3 module to:

1. reset the chip
2. switch to Soft-AP mode on channel 1 (WPA2-PSK)
3. set SSID VSD32-S3 and password vsd12345
4. print the AP’s IP and MAC addresses

Successful output in the Serial Monitor looks like:

Your VSD32-S3 is now broadcasting a Wi-Fi network that you can join from any phone or laptop.