usb_host_msd.c

microchip PIC18,pic24系列单片机USB驱动的开发源码

/******************************************************************************

  USB Host Mass Storage Device Driver

This is the Mass Storage Class driver file for a USB Embedded Host device.
This file should be used in a project with usb_host.c to provided the USB
hardware interface.

Acronyms/abbreviations used by this class:
    * LUN - Logical Unit Number
    * CBW - Command Block Wrapper
    * CSW - Command Status Wrapper

To interface with usb_host.c, the routine USBMSDClientInitialize() should be
specified as the Initialize() function, and USBMSDClientEventHandler() should
be specified as the EventHandler() function in the usbClientDrvTable[] array
declared in usb_config.h.

This driver can be configured to use transfer events from usb_host.c.  Transfer
events require more RAM and ROM than polling, but it cuts down or even
eliminates the required polling of the various USBxxxTasks functions.  For this
class, USBHostMSDTasks() is compiled out if transfer events from usb_host.c
are used.  However, USBHostTasks() still must be called to provide attach,
enumeration, and detach services.  If transfer events from usb_host.c
are going to be used, USB_ENABLE_TRANSFER_EVENT should be defined.  If transfer
status is going to be polled, USB_ENABLE_TRANSFER_EVENT should not be defined.

This driver can also be configured to provide mass storage transfer events to
the next layer. Generating these events requires a small amount of extra ROM,
but no extra RAM.  The layer above this driver must be configured to receive
and respond to the events.  If mass storage transfer events are going to be
sent to the next layer, USB_MSD_ENABLE_TRANSFER_EVENT should be defined.  If
mass storage transfer status is going to be polled,
USB_MSD_ENABLE_TRANSFER_EVENT should not be defined.

Since mass storage is performed with bulk transfers, USB_SUPPORT_BULK_TRANSFERS
must be defined. For maximum throughput, it is recommended that
ALLOW_MULTIPLE_BULK_TRANSACTIONS_PER_FRAME be defined.  For maximum
compatibility with mass storage devices, it is recommended that
ALLOW_MULTIPLE_NAKS_PER_FRAME not be defined.

* FileName:        usb_host_msd.c
* Dependencies:    None
* Processor:       PIC24/dsPIC30/dsPIC33/PIC32MX
* Compiler:        C30 v2.01/C32 v0.00.18
* Company:         Microchip Technology, Inc.

Software License Agreement

The software supplied herewith by Microchip Technology Incorporated
(the 揅ompany