Rainbow Electronics AT89C5132 - Manual (Page 10)

10
AT89C5132
4256A–USB–06/03
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 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.
DFU Specific Requests In addition of the USB standard requests, 7 DFU class-specific requests are employed
to accomplish the upgrade operations, see the following table.
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 5. USB Parameters
Table 4. 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