# USB Host MSC (Mass Storage Class) Driver This directory contains an implementation of a USB Mass Storage Class Driver implemented on top of the [USB Host Library](https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/peripherals/usb_host.html). MSC driver allows access to USB flash drivers using the BOT “Bulk-Only Transport” protocol and the Transparent SCSI command set. ## Usage - First, usb host library has to be initialized by calling `usb_host_install` - USB Host Library events have to be handled by invoking `usb_host_lib_handle_events` periodically. In general, an application should spawn a dedicated task handle USB Host Library events. However, in order to save RAM, an already existing task can also be used to call `usb_host_lib_handle_events`. - Mass Storage Class driver is installed by calling `usb_msc_install` function along side with configuration. - Supplied configuration contains user provided callback function invoked whenever MSC device is connected/disconnected and optional parameters for creating background task handling MSC related events. Alternatively, user can call `usb_msc_handle_events` function from already existing task. - After receiving `MSC_DEVICE_CONNECTED` event, user has to install device with `usb_msc_install_device` function, obtaining MSC device handle. - USB descriptors can be printed out with `usb_msc_print_descriptors` and general information about MSC device retrieved with `from usb_msc_get_device_info` function. - Obtained device handle is then used in helper function `usb_msc_vfs_register` mounting USB Disk to Virtual filesystem. - At this point, standard C functions for accessing storage (`fopen`, `fwrite`, `fread`, `mkdir` etc.) can be carried out. - In order to uninstall the whole USB stack, deinitializing counterparts to functions above has to be called in reverse order. ## Known issues - Driver only supports USB 2.0 flash drives using the BOT “Bulk-Only Transport” protocol and the Transparent SCSI command set - Composite USB devices are not supported ## Examples - For an example, refer to [msc_host_example](https://github.com/espressif/esp-idf/tree/master/examples/peripherals/usb/host/msc) ## Troubleshooting After connecting composite USB device, driver prints `COMPOSITE DEVICES UNSUPPORTED`
idf.py add-dependency "espressif/usb_host_msc^1.0.3"