AVR32 USB Software Framework for Mass Storage

License

Use of this program is subject to Atmel's End User License Agreement.

Please read the Copyright Notice at the bottom of this page.

Description

This embedded application source code illustrates how to implement a USB mass-storage application on the AVR32 microcontroller.

As the AVR32 implements a device/host USB controller, the embedded application can operate in one of the following USB operating modes:

The next table shows the customization to do (into the conf_usb.h and conf_access.h configuration files) in order to support one of the USB operating modes:
USB device USB reduced-host USB dual-role
conf_usb.h
USB_DEVICE_FEATURE ENABLED DISABLED ENABLED
USB_HOST_FEATURE DISABLED ENABLED ENABLED
conf_access.h
LUN_USB DISABLED ENABLED ENABLED
ACCESS_USB ENABLED DISABLED ENABLED

To optimize embedded code/RAM size and reduce the number of source modules, the application can be configured to use one and only one of these operating modes.

About the Sample Application

By default the sample code is delivered with a simple preconfigured dual-role USB application. It means that the code generated allows to operate as a device or a host depending on the USB ID pin:

appli_evk1100_device.jpg

EVK1100 USB Device Mode

appli_evk1101_device.jpg

EVK1101 USB Device Mode

appli_evk1104_device.jpg

EVK1104 USB Device Mode

appli_evk1105_device.jpg

EVK1105 USB Device Mode

appli_evk1100_host.jpg

EVK1100 USB Host Mode

appli_evk1101_host.jpg

EVK1101 USB Host Mode

appli_evk1104_host.jpg

EVK1104 USB Host Mode

appli_evk1105_host.jpg

EVK1105 USB Host Mode

Using the USB Device Mode

Connect the application to a USB mass-storage host (e.g. a PC) with a mini-B (embedded side) to A (PC host side) cable. The application will behave as a USB key. It will allow to access files on the on-board virtual, data flash and SD/MMC memories.

Using the USB Host Mode

Connect the application to a USB mass-storage device (e.g. a USB key). The application will behave as a USB mass-storage reduced host. It will allow to exchange files between the on-board virtual, data flash and SD/MMC memories and the mass-storage device.

Using the USB Shell Terminal

Connected to a serial terminal the uShell command line interpreter allows to:

Architecture

As illustrated in the figure below, the application entry point is located in the mass_storage_example.c file. The main function first performs the initialization of services and tasks and then runs them in an infinite loop.

The sample mass-storage application is based on four different tasks:

arch_full.jpg

Architecture Overview

Configuration

The sample application is configured to implement both host and device functionalities. Of course it can also be configured to be used only in device or reduced-host mode (see the conf_usb.h file). Depending on the USB operating mode selected, the USB task will call either the USB host task (usb_host_task.c), or the USB device task (usb_device_task.c) to manage USB specification chapter 9 requests.

Main Files

Example configuration files can be found in SERVICES\USB\CLASS\MASS_STORAGE\EXAMPLES\CONF.

Limitations

Some mass-storage devices do not present directly a mass-storage-class interface, which may e.g. be hidden behind a hub-class device. These devices are not supported by this example and the current mass-storage software framework.

Contact Information

For further information, visit Atmel AVR32.
Support and FAQ: http://support.atmel.no/

Copyright Notice

Copyright (c) 2009 Atmel Corporation. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of Atmel may not be used to endorse or promote products derived from this software without specific prior written permission.

4. This software may only be redistributed and used in connection with an Atmel AVR product.

THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE


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