12

4256B–USB–03/06

AT89C5132

Protocol

Device Firmware

Upgrade Introduction

Device Firmware Upgrade is the mechanism for accomplishing the task of upgrading the device

firmware. Any class of USB device can exploit this capability by supporting the requirements

specified in this document.

Because it is impractical for a device to concurrently perform both DFU operations and its nor-

mal run-time activities, those normal activities must cease for the duration of the DFU

operations. Doing so means that the device must change its operating mode; i.e., a printer is not

a printer while it is undergoing a firmware upgrade; it is a PROM programmer. However, a

device that supports DFU is not capable of changing its mode of operation on its own. External

(human or host operating system) intervention is required.

DFU Specific

Requests

In addition of the USB standard requests, 7 DFU class-specific requests are employed to

accomplish the upgrade operations, see Figure 4.

DFU Descriptors Set

The device exports the DFU descriptor set, which contains:

•

A DFU device descriptor

•

A single configuration descriptor

•

A single interface descriptor (including descriptors for alternate settings, if present)

•

A single functional descriptor

DFU Device Descriptor

This descriptor is only present in the DFU mode descriptor set. The DFU class code is reported

in the bDeviceClass field of this descriptor.

Table 9. USB Parameters

Table 8. DFU Class-specific Requests

bmRequestType

bRequest

wValue

wIndex

wLength

Data

0010 0001b

DFU_DETACH (0)

wTimeout

Interface (4)

Zero

none

0010 0001b

DFU_DNLOAD (1)

wBlock

Interface (4)

Length

Firmware

1010 0001b

DFU_UPLOAD (2)

wBlock

Interface (4)

Length

Firmware

1010 0001b

DFU_GETSTATUS (3)

Zero

Interface (4)

6

Status

0010 0001b

DFU_CLRSTATUS (4)

Zero

Interface (4)

Zero

none

1010 0001b

DFU_GETSTATE (5)

Zero

Interface (4)

1

State

0010 0001b

DFU_ABORT (6)

Zero

Interface (4)

Zero

none

Parameter

ATMEL – AT89C5132 Bootloader

Vendor ID

0x03EB

Product ID

0x2FFF

Release Number

0x0000