USB MTP Device Example (DFS + RAM DISK)

Source code path: example/cherryusb/device/mtp

Supported Platforms

sf32lb52-lcd_n16r8_hcpu
sf32lb58-lcd_n16r32n1_dpi_hcpu

Overview

This example demonstrates a CherryUSB MTP device implementation using RT-Thread DFS and POSIX APIs. It creates a 64 KiB RAM block device (mtp_ram), formats it with the elm filesystem, and exposes it through MTP.

After connecting to a host PC, the device appears as CherryUSB MTP DEMO, and files can be browsed, copied, and deleted from the file manager. By default, a sample file cherryusb.txt is created in the root directory.

How to Use the Example

Hardware Requirements

Before running this example, prepare the following:

A supported development board.
A USB cable with data transfer capability (a stable Type-C data cable is recommended).
A host that supports MTP (Windows/Linux/macOS).

menuconfig Configuration

This example depends on the following key options:

CONFIG_PKG_CHERRYUSB_DEVICE=y
CONFIG_PKG_CHERRYUSB_DEVICE_MTP=y
CONFIG_RT_USING_DFS_ELMFAT=y

To adjust object count, pathname length, thread stack size, and related options, refer to:

src/usb_config.h

Build and Flash

Switch to the example project directory and run scons:

scons –board=sf32lb58-lcd_n16r32n1_dpi_hcpu -j8

Then switch to project/build_xx and run uart_download.bat. Select the serial port as prompted:

.\uart_download.bat

For detailed build and flashing instructions, refer to Quick Start.

Expected Result

After boot and USB connection, the expected behavior is:

The host detects an MTP device (product name: CherryUSB MTP DEMO).
The sample file cherryusb.txt is visible.
Basic file operations (read/write/delete/rename) work as expected.

Troubleshooting

If the host cannot enumerate the device or file operations fail, check:

Whether CONFIG_RT_USING_DFS_ELMFAT is enabled. If not, errors like File system (elm) was not found may occur.
Whether the USB cable supports data transfer (charge-only cables will fail).
Whether MTP/DFS-related errors appear in board serial logs.

If you encounter issues, please submit an issue on GitHub.

Reference Documentation

Changelog

Version	Date	Notes
0.0.1	06/2026	Initial version with MTP (DFS + RAM Disk) example description