AT90USB64X データシートの表示（PDF） - Atmel Corporation
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AT90USB64X Datasheet PDF : 28 Pages
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4.5.3
Device State
The state reported is the current state of the device up to transmission of the response. The val-
ues specified in the bState field are identical to those reported in DFU_GETSTATUS.
bmRequestType
1010 0001b
bRequest
DFU_GETSTATE (5)
wValue
Zero
wIndex
Interface (4)
wLength
1
Data
State
4.5.4
DFU_ABORT request
The DFU_ABORT request forces the device to exit from any other state and return to the
DFU_IDLE state. The device sets the OK status on receipt of this request. For more information,
see the corresponding state transition summary.
bmRequestType
1010 0001b
bRequest
DFU_ABORT (6)
wValue
Zero
wIndex
Interface (4)
wLength
0
Data
None
4.6 Programming the Flash or EEPROM Data
The firmware image is downloaded via control-write transfers initiated by the DFU_DNLOAD
class-specific request. The host sends between bMaxPacketSize0 and wTransferSize bytes to
the device in a control-write transfer. Following each downloaded block, the host solicits the
device status with the DFU_GETSTATUS request.
As described in the USB DFU Specification, "Firmware images for specific devices are, by defi-
nition, vendor specific. It is therefore required that target addresses, record sizes, and all other
information relative to supporting an upgrade are encapsulated within the firmware image file. It
is the responsibility of the device manufacturer and the firmware developer to ensure that their
devices can process these encapsulated data. With the exception of the DFU file suffix, the con-
tent of the firmware image file is irrelevant to the host."
Firmware image:
• 32 bytes: Command
• X bytes: X is the number of byte (00h) added before the first significant byte of the firmware.
The X number is calculated to align the beginning of the firmware with the flash page. X =
start_address [32]. For example, if the start address is 00AFh (175d), X = 175 [32] = 15.
• The firmware
• The DFU Suffix on 16 Bytes.
Table 4-7. DFU File Suffix
Offset
-0
-4
Field
dwCRC
bLength
Size
4
1
-5
ucDfuSignature
3
-8
bcdDFU
2
Value Description
Number The CRC of the entire file, excluding dwCRC
16
The length of this DFU suffix including dwCRC
5 : 44h
6 : 46h
7 : 55h
The unique DFU signature field
BCD
DFU specification number
0100h
8
7618C–AVR–07/08
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