USB大容量存储设备(MSD)引导加载程序(英文)

1 Introduction Freescale offers a broad selection of microcontrollers that feature universal serial bus (USB) access. A product with a USB port allows very easy field updates of the firmware. This application note describes a mass storage device (MSD) USB bootloader that has been written to work with several Freescale USB families. A device with this bootloader is connected to a host computer, and the bootloader enumerates as a new drive. The new firmware is copied onto this drive, and the device reprograms itself. Freescale does offer other bootloaders. For example, application note AN3561, "USB Bootloader for the MC9S08JM60," describes a USB bootloader that was written for the Flexis JM family. The MSD bootloader described in this application note is offered as another option, and has these advantages: • It does not require a driver to be installed on the host. • It does not require an application to run on the host. • Any user can use it with a little training. The only action required is to copy a file onto a drive. • It can be used with many different host operating systems since it requires no host software or driver This bootloader was specifically written for several families of Freescale microcontrollers that share similar USB peripherals. These families include, but are not limited to, the following: • Flexis JM family MCF51JM This bootloader will work on all of these devices with few changes, and examples were written and tested on the following Freescale microcontrollers: • MCF52259 — 32-bit ColdFire V2 with USB, Ethernet, CAN, and external bus • MCF51JM128 — 32-bit ColdFire V1 with USB (part of the Flexis JM family) • MK60N512 — ARM® Cortex™-M4 architecture with USB 2.0 full-speed OTG controller and 10/100 Mbps Ethernet MAC USB stack used: • Freescale’s USB Stack with PHDC support v3.0 Tested development boards: • TWR-MCF5225X-KIT — low-cost tower kit for MCF5225x family • DEMOJM — low-cost development board for Flexis JM family • TWR-K60N512-KIT — low-cost tower kit for Kinetis K60 family Tested operating systems: • Windows XP Pro with Service Pack 2 and Service Pack 3 Tested development tool: • CodeWarrior for Microcontrollers v10.1 • CodeWarrior for Microcontrollers v6.3 • CodeWarrior for ColdFire v7.2