1. Introduction
The XH-C2X ESP8684H4 is a compact and powerful WiFi and Bluetooth Low Energy (BLE) module designed for various IoT applications. It features a 32-bit processor and 4MB of Flash memory, offering robust connectivity and processing capabilities. This module serves as a low-energy replacement for modules like the ESP-01S.
2. Specifications
| Category | Feature | Description |
|---|---|---|
| Wi-Fi | Frequency Range | 2.4~2.5 GHz |
| Protocol | IEEE 802.11b/g/n | |
| Modes | Station/softAP/SoftAP+station | |
| Bluetooth | Protocol | Low Energy Bluetooth (Bluetooth LE): Bluetooth 5, Bluetooth mesh |
| RF | NZIF Receiver with -98 dBm Sensitivity | |
| Hardware | Module Interface | GPIO, SPI, UART, I2C, I2S, IR, LED PWM, Temperature Sensor, SAR ADC, General Timers, Watchdog Timers |
| Onboard Clock | 26 MHz Crystal, 32 kHz Crystal | |
| Operating Voltage | 3.0-3.6V DC | |
| Operating Current | Average: 80 mA | |
| Operating Temperature Range | -40°C to +85°C | |
| Package Size | 16 mm x 24 mm x 3 mm | |
| Software | Security Mechanism | WPA/WPA2/WPA2-Enterprise/WPS |
| Encryption Types | AES/RSA/ECC/SHA | |
| Firmware Upgrade | UART Download/OTA (Over the network/Through the host to download and write firmware) | |
| Software Development | Supports cloud server development/SDK for user firmware development | |
| Network Protocol | IPv4, IPv6, SSL, TCP/UDP/HTTP/FTP/MQTT | |
| User Configuration | AT+ Command Set, Cloud Server, Android/iOS APP |
The module features a RISC-V 32-bit CPU running at 120MHz, 212K SRAM, 576K ROM, 4MB Flash, and supports various peripherals like UART, I2C, SPI, IR, PWM, and ADC.
Figure 1: Module Structure Diagram illustrating the internal components and interfaces.
3. Setup and Pinout
Before operating the XH-C2X module, ensure proper power supply and pin connections. The module requires a stable DC voltage between 3.0V and 3.6V.
3.1 Pinout Diagram
Figure 2: Pinout diagram for the XH-C2X module, showing pin names, styles (I/O, Power), and descriptions.
| NO. | Name | Style | Description |
|---|---|---|---|
| 1 | RXD0 | I/O | GPIO19, U0RXD |
| 2 | IO9 | I/O | High: chip enable; Low: download mode; |
| 3 | IO8 | I/O | GPIO8, internal pull-up. |
| 4 | GND | P | Ground |
| 5 | VCC | P | 3V3 supply (500mA or more) |
| 6 | RST | I/O | Low level: chip off; Note that the EN pin cannot be left floating. |
| 7 | EN | I/O | High level: chip enable; Be careful not to leave the EN pin floating. |
| 8 | TXD0 | I/O | GPIO20, U0TXD |
3.2 Minimum System Wiring
For basic operation, connect the module as shown in the minimum system diagram. Ensure the power supply is 3.3V DC and can provide at least 500mA. The maximum output current for module IO is 12mA.
Figure 3: Minimum System Wiring Diagram for the XH-C2X module, showing essential connections for basic functionality.
3.3 Automatic Download Circuit
To facilitate automatic software download, connect the EN and GPIO9 pins of the module to the DTR and RTS pins of your serial chip. This configuration allows the module to enter download mode automatically.
Figure 4: Automatic Download Circuit Diagram, detailing connections for automated firmware flashing.
3.4 Firmware Flashing
When burning firmware, use a tool like flash_download_tool_3.9.3.exe. It is crucial to select 'ESP32-C2' as the ChipType in the flashing software for correct operation.
Figure 5: Screenshot of the firmware download tool, highlighting the selection of 'ESP32-C2' as the ChipType.
Download Mode Logic:
- FLASH Download Mode: IO9 must be at a low level when the module resets and powers up.
- Normal Working Mode: IO9 must be at a high level when the module resets and powers up.
4. Operating Instructions
The XH-C2X module supports various operating modes and configurations for both Wi-Fi and Bluetooth functionalities.
4.1 Wi-Fi Operation
The module can operate in Station, SoftAP, or a combined SoftAP+Station mode. Configure these modes using the provided SDK or AT+ commands. Security mechanisms include WPA/WPA2/WPA2-Enterprise/WPS with AES/RSA/ECC/SHA encryption types.
4.2 Bluetooth Operation
The module supports Bluetooth 5 and Bluetooth mesh protocols, leveraging its Low Energy (LE) capabilities. Develop Bluetooth applications using the SDK.
4.3 Software Development and Configuration
The module supports software development using an SDK for user firmware development and cloud server integration. User configuration can be done via AT+ Command Set, cloud servers, or dedicated Android/iOS applications. It supports common network protocols such as IPv4, IPv6, SSL, TCP/UDP/HTTP/FTP, and MQTT.
5. Maintenance
To ensure the longevity and optimal performance of your XH-C2X module, follow these general maintenance guidelines:
- Environmental Conditions: Keep the module in a dry environment, away from moisture and corrosive substances. Operate within the specified temperature range of -40°C to +85°C.
- Handling: Handle the module with care to avoid physical damage to components or pins. Use anti-static precautions when handling to prevent electrostatic discharge (ESD).
- Cleaning: If necessary, gently clean the module with a soft, dry brush or compressed air to remove dust. Avoid using liquids or harsh chemicals.
- Power Supply: Always use a stable and regulated power supply within the 3.0-3.6V DC range. Incorrect voltage can damage the module.
6. Troubleshooting
If you encounter issues with your XH-C2X module, consider the following troubleshooting steps:
- No Power/Module Not Responding:
- Verify the power supply voltage is within 3.0-3.6V DC and can provide sufficient current (at least 500mA).
- Check all power connections for proper contact and polarity.
- Ensure the RST and EN pins are correctly handled (RST active low, EN high for chip enable, neither left floating).
- Firmware Upload Failure:
- Confirm that the serial chip's DTR and RTS are correctly connected to the module's EN and GPIO9 for automatic download mode.
- Ensure 'ESP32-C2' is selected as the ChipType in your flashing software.
- Check UART connections (RXD to TXD, TXD to RXD) and baud rate settings.
- Wi-Fi/Bluetooth Connectivity Issues:
- Verify antenna connections (if using an external antenna).
- Check Wi-Fi credentials (SSID, password) and network configuration.
- Ensure the module is in the correct Wi-Fi mode (Station, SoftAP).
- For Bluetooth, ensure devices are discoverable and within range.
- Unexpected Behavior:
- Review your code for logical errors.
- Check for any short circuits or incorrect wiring on your development board.
- Consider reflashing the firmware.
7. User Tips
While specific user reviews or Q&A were not provided, here are some general tips for working with the XH-C2X ESP8684H4 module:
- Start Simple: Begin with basic examples (e.g., blinking an LED, connecting to Wi-Fi) to familiarize yourself with the module's programming and functionality.
- Power Supply Stability: Always use a high-quality, stable 3.3V power supply. Fluctuations can lead to unpredictable behavior or damage.
- Pin Management: Pay close attention to the pinout diagram. Incorrect pin connections are a common source of issues. Avoid leaving critical pins like EN or RST floating.
- Development Environment: Utilize the official Espressif SDK or popular frameworks like Arduino IDE with ESP32-C2 board support for easier development.
- Community Resources: Leverage online forums and communities for ESP32-C2/ESP8684H4 modules. Many common problems have already been solved and documented by other users.
8. Warranty and Support
For warranty information and technical support, please contact the seller or manufacturer directly. Keep your purchase receipt or order details handy when requesting support.