USB Mass Storage¶

Overview¶

The USB Mass Storage sample demonstrates the 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.

Requirements¶

Before you start, check that you have the required hardware and software:

• 1x nRF52840 MDK USB Dongle(or w/Case option)
• A computer running macOS, Linux, or Windows 7 or newer

Building the sample¶

Before you start building, remember to set up the environment first.

Use the following steps to build the USB Mass Storage sample on the command line.

1. Open a terminal window.

2. Go to my-workspace/ncs-playground directory created in the Setting up the environment section.

   1	cd my-workspace/ncs-playground

3. Build the sample using the west command, specifying the board (following the -b option) as dongle_nrf52840. There are multiple configurations can be chosen:

   RAM-diskRAM-disk with FATFSFLASH-disk with FATFSFLASH-disk with LittleFS

   1	west build -p always -b dongle_nrf52840 samples/usb/mass

   1	west build -p always -b dongle_nrf52840 samples/usb/mass -- -DCONFIG_APP_MSC_STORAGE_RAM=y

   1	west build -p always -b dongle_nrf52840 samples/usb/mass -- -DCONFIG_APP_MSC_STORAGE_FLASH_FATFS=y

   1	west build -p always -b dongle_nrf52840 samples/usb/mass -- -DCONFIG_APP_MSC_STORAGE_FLASH_LITTLEFS=y

   Tip

   The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.

4. After running the west build command, the build files can be found in build/zephyr.

Flashing the firmware¶

The sample is designed to work with the UF2 Bootloader, so that you can easily flash the sample using the UF2 Bootloader. The firmware can be found in build/zephyr with the name zephyr.uf2.

To flash the firmware, complete the following steps:

1. Push and hold the button and plug your dongle into the USB port of your computer. Release the button after your dongle is connected. The RGB LED turns green.

2. It will mount as a Mass Storage Device called UF2BOOT.

3. Drag and drop zephyr.uf2 onto the UF2BOOT volume. The RGB LED blinks red fast during flashing.

4. Re-plug the dongle and the sample will start running.

Testing¶

After flashing the firmware to your dongle, complete the following steps to test it:

1. Plug the dongle into the USB port of your computer.
2. The dongle will be detected as an USB disk.