USB Mass Storage Sample Application


This sample app demonstrates use of a USB Mass Storage driver by the Zephyr project. This very simple driver enumerates a board with either RAM or FLASH into an USB disk. This sample can be found under samples/subsys/usb/mass in the Zephyr project tree.


This project requires a USB device driver, and either 16KiB of RAM or a FLASH device.

Building and Running

This sample can be built for multiple boards. The selection between a RAM-based or a FLASH-based disk can be selected using the overlay-ram-disk.conf or the overlay-flash-disk.conf overlays. In this example we will build the sample with a RAM-based disk and for the quark_se_c1000_devboard board:

# On Linux/macOS
cd $ZEPHYR_BASE/samples/subsys/usb/mass
mkdir build && cd build
# On Windows
cd %ZEPHYR_BASE%\samples\subsys\usb\mass
mkdir build & cd build
cmake -GNinja -DBOARD=quark_se_c1000_devboard -DOVERLAY_CONFIG="overlay-ram-disk.conf" ..

After you have built and flashed the sample app image to your board, plug the board into a host device, for example, a PC running Linux. The board will be detected as shown by the Linux journalctl command:

$ journalctl -k -n 17
usb 2-2.4: new full-speed USB device number 29 using xhci_hcd
usb 2-2.4: New USB device found, idVendor=2fe3, idProduct=0100, bcdDevice= 0.11
usb 2-2.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-2.4: Product: Zephyr MSC sample
usb 2-2.4: Manufacturer: ZEPHYR
usb 2-2.4: SerialNumber: 0.01
usb-storage 2-2.4:1.0: USB Mass Storage device detected
scsi host3: usb-storage 2-2.4:1.0
scsi 3:0:0:0: Direct-Access     ZEPHYR   ZEPHYR USB DISK  0.01 PQ: 0 ANSI: 0 CCS
sd 3:0:0:0: Attached scsi generic sg1 type 0
sd 3:0:0:0: [sdb] 32 512-byte logical blocks: (16.4 kB/16.0 KiB)
sd 3:0:0:0: [sdb] Write Protect is off
sd 3:0:0:0: [sdb] Mode Sense: 03 00 00 00
sd 3:0:0:0: [sdb] No Caching mode page found
sd 3:0:0:0: [sdb] Assuming drive cache: write through
sd 3:0:0:0: [sdb] Attached SCSI removable disk

The disk contains a simple README.TXT file with the following content:

This is a  RAM Disk based  USB Mass Storage demo for Zephyr.

Files can be added or removed like with a simple USB disk, of course within the 16KiB limit.