USB Disk Read-write Module CH376 For Arduino

Specifications

• Primary Controller: WCH CH376S USB Host/Device Controller
• Operating Voltage: 3.3V DC or 5V DC (subject to board jumper configuration)
• USB Standard: USB 2.0 Full-Speed (12 Mbps) and Low-Speed (1.5 Mbps)
• Operating Modes: USB Host Mode and USB Device/Slave Mode
• File System Support: FAT12, FAT16 and FAT32
• Host Communication Interfaces: 8-bit Parallel, SPI and Asynchronous UART
• SPI Clock Speed: Up to 24 MHz
• UART Baud Rate: Configurable up to 3 Mbps
• Supported Storage Devices: Compatible USB flash drives, USB card readers and supported USB mass-storage devices

Safety Warnings

• Logic Voltage Jumpers: Always configure the onboard voltage jumper to match your microcontroller's logic level (5V for standard Arduino Uno; 3.3V for STM32/ESP32) before applying power to avoid overvoltage damage to host GPIO pins.
• Inrush Current Management: Never hot-plug power-hungry external mechanical hard drives or unverified USB devices directly into the module's USB port without external regulated power, as excessive load can damage the CH376S power traces.
• Ground Reference: Microcontroller GND and module GND must be firmly bonded together; a floating ground will desynchronize the SPI/UART clock and cause command timeout errors.

Accessories Included in the Box

• 1× CH376S USB Module U Disk Read Write Module (with pre-soldered dual-row headers and USB Type-A port) 

 Frequently Asked Question

• Can the CH376S save sensor readings directly to a USB flash drive?
  Yes. A compatible microcontroller can send sensor data to the CH376S, which can write it to a file on a supported USB flash drive. This is useful for standalone data loggers.
• Does the microcontroller need to implement the FAT file system?
  No. The CH376S provides built-in FAT12, FAT16, and FAT32 file-system handling, reducing the amount of file-management code required on the microcontroller.
• Can I use this module to append new readings to an existing file?
  Yes, provided the firmware uses the appropriate file-positioning and write commands. Your program must manage the file location and ensure new data is written where intended.
• Can the module read a configuration file when a device starts up?
  Yes. A compatible microcontroller can instruct the CH376S to open and read a configuration file from a supported USB drive during startup.
• What happens if the USB drive is removed while a file is being written?
  The write operation may fail, and the file could become incomplete or corrupted. Complete pending writes and close the file before removing the drive.
• Can I connect the CH376S to an ESP32 or Arduino using SPI?
  Yes. SPI is one of its supported communication interfaces. The selected logic voltage, wiring, firmware library, and available pins must match your development board.
• Can this module access individual files inside folders on a USB drive?
  Yes. Its file-system commands support directory navigation and file access, allowing firmware to work with files stored in folders rather than only in the root directory.
• Will a USB flash drive work immediately after plugging it in?
  Not necessarily. Your firmware must initialize the module, detect and mount the supported storage device, and handle communication or file-system errors before accessing files.
• Can I use this module to transfer files between a microcontroller and a computer?
  It can store files on USB media that can later be connected to a computer. However, it does not automatically create a direct USB data link between the microcontroller and computer.