AT89C51SND1_06 ATMEL [ATMEL Corporation], AT89C51SND1_06 Datasheet - Page 12

• Manufacturer Part Number: AT89C51SND1_06
• Description: USB Microcontrollers
• Manufacturer: ATMEL [ATMEL Corporation]

Protocol
Device Firmware
Upgrade Introduction
DFU Specific
Requests
DFU Descriptors Set
DFU Device Descriptor
12
AT89C51SND1
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.
In addition of the USB standard requests, 7 DFU class-specific requests are employed to
accomplish the upgrade operations, see Figure 4.
Table 8. DFU Class-specific Requests
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 9. USB Parameters
bmRequestType
0010 0001b
0010 0001b
1010 0001b
1010 0001b
0010 0001b
1010 0001b
0010 0001b
A DFU device descriptor
A single configuration descriptor
A single interface descriptor (including descriptors for alternate settings, if present)
A single functional descriptor
DFU_GETSTATUS (3)
DFU_CLRSTATUS (4)
DFU_GETSTATE (5)
DFU_DNLOAD (1)
DFU_UPLOAD (2)
Release Number
DFU_DETACH (0)
DFU_ABORT (6)
Parameter
Product ID
Vendor ID
bRequest
wTimeout
wValue
wBlock
wBlock
Zero
Zero
Zero
Zero
Interface (4)
Interface (4)
Interface (4)
Interface (4)
Interface (4)
Interface (4)
Interface (4)
wIndex
ATMEL - AT89C51SND1 Bootloader
0x03EB
0x2FFF
0x0000
wLength
Length
Length
Zero
Zero
Zero
6
1
4254C–MP3–03/06
Firmware
Firmware
Status
State
Data
none
none
none