WT9932S31-TINY Board Features

Note: Disconnect power before connecting a camera. Check the pin sequence, contact side, cable orientation, and supply voltage of the 24Pin DVP FPC connector. The same number of pins does not guarantee electrical compatibility.

1. Introduction

WT9932S31-TINY is a compact development board in Wireless-tag's TINY series. It is based on the WT0132S31-S1 module with Espressif's ESP32-S31 at its core, uses a four-layer PCB, and measures approximately 54 × 28 mm. The board combines wireless connectivity, camera capture, storage, and general-purpose peripheral expansion in a small footprint, making it suitable for space-constrained embedded applications and prototyping.

ESP32-S31 features a dual-core RISC-V processor running at up to 320 MHz and supports 2.4 GHz Wi-Fi 6, Bluetooth Low Energy, Bluetooth Classic, Zigbee, and Thread. The board provides 16 MB Flash and 32 MB PSRAM, an onboard DVP camera interface, a four-line MicroSD card slot, an RGB indicator, EN/RESET and BOOT buttons, and two USB Type-C ports labeled FUSB and HUSB. These resources support image capture, data storage, and evaluation of multiprotocol IoT applications.

1.1 Core Hardware Configuration

• Core module: Wireless-tag WT0132S31-S1.
• Main processor: Espressif ESP32-S31, dual-core RISC-V, running at up to 320 MHz.
• Memory: 16 MB Flash and 32 MB PSRAM.
• Wireless connectivity: 2.4 GHz Wi-Fi 6, Bluetooth Low Energy, Bluetooth Classic, Zigbee, and Thread, with an external antenna connected through the module's RF interface.
• Camera interface: A 24Pin DVP FPC connector with 0.5 mm pitch, designed for the OV3660 pin sequence; 2 × 9 DVP expansion header pads with 2.54 mm pitch are provided on the back.
• Storage interface: An insertion/removal-type MicroSD/TF card slot supporting 4-bit mode.
• Pin headers: Two 21Pin headers, H1 and H2, with 2.54 mm pitch for connection to breadboards or perfboards.
• Debugging resources: USB Serial/JTAG, high-speed USB 2.0 OTG, UART0, an RGB LED, and reset and download-mode buttons.
• Power design: Power combining and reverse-current protection for the two USB Type-C inputs, an onboard 3.3 V DC-DC converter, and 2.8 V and 1.5 V LDO regulators for the camera.
• Board dimensions: Approximately 54 × 28 mm; use the CAD files and 3D model for assembly dimensions.

1.2 Design Features

1. High performance in a compact size: The WT0132S31-S1 module forms the core system, while the four-layer PCB balances a compact layout with peripheral expansion.
2. DVP image capture: The onboard camera FPC connector accepts a compatible camera module for image capture, processing, and video transmission development.
3. Shared DVP and GPIO expansion: The U5 pads on the back have no pin header fitted by default. When no camera is used, a header can be soldered to use the corresponding signals for general-purpose peripheral expansion.
4. Dual USB ports: J2/FUSB is used for firmware flashing, logging, and JTAG debugging; J1/HUSB is used for high-speed USB application development.
5. Onboard storage and interaction: The MicroSD card slot supports data logging, while the RGB indicator and BOOT button provide status indication and basic interaction.
6. Breadboard-friendly headers: The headers on both sides use 2.54 mm pitch for quick connection to sensors, control devices, or a custom carrier board.
7. Convenient mounting: Mounting features along the board edges support installation with retaining plates, screws, or a custom base.

1.3 Applications

• IoT devices: Evaluate wireless applications using Wi-Fi, Bluetooth, and 802.15.4, connect sensors, and implement device control.
• Image capture and vision prototypes: Connect a compatible DVP camera for image capture, USB video transmission, and evaluation of vision applications.
• Data logging: Use a MicroSD card to save captured data, logs, or application files.
• Education and prototyping: Support embedded systems education, maker projects, customer solution evaluation, and custom carrier board development.

1.4 Development Advantages

• The module integrates the core system and RF circuitry, allowing the development board design to serve as a reference for further development.
• The hardware design is published on JLC's OSHWHub open-source hardware platform. WT_BSP provides board support and peripheral examples for the software.
• Start with basic examples such as RGB, buttons, and SDMMC, then evaluate camera and USB applications. See Board Resources for the relevant links.

2. Hardware Peripherals

2.1 Components

2.2 Connector Footprints

3. Pin Descriptions

3.1 H1 Header

H1 is a 21Pin header with 2.54 mm pitch. The H1 and H2 tables below list positions from top to bottom in the front-facing orientation shown in the pinout diagram on the resources page. "Position" identifies locations in the diagram; also refer to the schematic for connector pad numbers.

3.2 H2 Header

H2 is a 21Pin header with 2.54 mm pitch. TX0 and RX0 correspond to IO58 and IO59, respectively; IO20 through IO25 are shared with the onboard MicroSD card slot.

Note: IO36, IO37, IO60, and IO61 are chip boot configuration pins. External circuitry must maintain the correct levels when these pins are sampled at startup. IO61 is connected to the onboard BOOT button.

3.3 J1 and J2 USB Type-C Ports

When both ports are connected, the power combining circuit gives priority to J2/FUSB. When developing USB Host applications with J1, provide a separate power solution appropriate for the peripheral.

3.4 CARD1 MicroSD/TF Card Interface

CARD1 is an insertion/removal-type card slot supporting 4-bit mode. The card slot supply is 3.3 V.

The accompanying WT_BSP SDMMC configuration uses the on-chip LDO 1 to configure the SD I/O supply as 1.8 V. Verify the card slot supply and the controller's signal supply configuration separately; the signal levels cannot be inferred from the card slot VCC alone. Before reassigning IO20 through IO25 to other functions, check the chip power domain, software configuration, and voltage-level requirements of the connected devices.

3.5 FPC2 DVP Camera Interface

FPC2 is a drawer-type, bottom-contact, 24Pin camera connector with 0.5 mm pitch, designed for the OV3660 pin sequence. The directions of the data and timing signals below are relative to the main controller. Camera signals Y2 through Y9 correspond to the controller's eight-bit image data input.

PWDN and RESET have fixed bias levels provided by the onboard circuitry and are not connected to GPIO pins that software can control directly. The accompanying software supports compatible GC2145 and OV3660 camera configurations. Select the driver or firmware that matches the camera actually connected.

3.6 U5 DVP Expansion Header

U5 consists of 2 × 9 horizontal surface-mount header pads with 2.54 mm pitch; no header is fitted by default. Its signals are shared with FPC2. Before connecting peripherals, ensure that they and the camera will not drive the same signal simultaneously.

4. Power Characteristics

Power the development board through either J2/FUSB or J1/HUSB.

• Use a good-quality USB-C cable that supports data transfer.
• When powering the board from a computer's USB port, a port capable of supplying at least 5 V/1 A is recommended.
• Both USB ports have power combining and reverse-current protection. When both are connected, J2/FUSB has priority.
• The onboard DC-DC converter converts the input supply to 3.3 V for the module and related peripherals. The camera circuitry has separate 2.8 V and 1.5 V LDO regulators.
• The 5V and 3.3V pins on H1 are power outputs and must not be used as external power inputs.
• The power pins on U5 and FPC2 are outputs at their respective voltages. Check the power direction before connecting expansion peripherals to avoid shorting different power nets together.
• J1/HUSB cannot supply power to external devices. If a USB peripheral requires power, design a separate power solution based on the actual circuit.
• The MicroSD card slot supply is 3.3 V. See the interface description above for the software configuration of the SD I/O supply.