at89c5131a ATMEL Corporation, at89c5131a Datasheet - Page 11

• Manufacturer Part Number: at89c5131a
• Description: Usb Microcontrollers
• Manufacturer: ATMEL Corporation

Protocol
Device Firmware Upgrade
Introduction
DFU Specific Requests
Table 1. DFU Class-specific Requests
DFU Descriptors Set
DFU Device Descriptor
4287C–USB–11/04
bmRequestType
0010 0001b
0010 0001b
1010 0001b
1010 0001b
0010 0001b
1010 0001b
0010 0001b
DFU_GETSTATUS (3)
DFU_CLRSTATUS (4)
DFU_GETSTATE (5)
DFU_DETACH (0)
DFU_DNLOAD (1)
DFU_UPLOAD (2)
DFU_ABORT (6)
bRequest
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 normal 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 program-
mer. 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.
In addition of the USB standard requests, 7 DFU class-specific requests are employed
to accomplish the upgrade operations (Table 1):
The device exports the DFU descriptor set, which contains:
•
•
•
•
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 2. USB Parameters
A DFU device descriptor
A single configuration descriptor
A single interface descriptor (including descriptors for alternate settings, if present)
A single functional descriptor
Release Number
wTimeout
wValue
wBlock
wBlock
Parameter
Zero
Zero
Zero
Zero
Product ID
Vendor ID
AT89C5131A USB Bootloader
Interface (4)
Interface (4)
Interface (4)
Interface (4)
Interface (4)
Interface (4)
Interface (4)
wIndex
Atmel – AT89C5131A Bootloader
wLength
Length
Length
Zero
Zero
Zero
6
1
0x2FFD
0x03EB
0x0000
Firmware
Firmware
Status
Data
State
none
none
none
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