Rainbow Electronics AT89C5132 - Manual (Page 12)

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AT89C5132
4256A–USB–06/03
Note: 1. Alternate settings can be used by an application to access additional memory seg-
ments. In this case, it is suggested that each alternate setting employs a string
descriptor to indicate the target memory segment; e.g., “EEPROM”. Details concern-
ing other possible uses of alternate settings are beyond the scope of this document.
However, their use is intentionally not restricted because it is anticipated that imple-
menters will devise additional creative uses for alternate settings.
DFU Functional Descriptor
Command Description This protocol allows to:
•
Initiate the communication
• Program the Flash Data
• Read the Flash Data
• Program Configuration Information
• Read Configuration and Manufacturer Information
• Erase the Flash
• Start the application
Overview of the protocol is detailed in Appendix-A.
Table 8. DFU Functional Descriptor
Offset Field Size Value Description
0 bLength 1 07h Size of this descriptor, in bytes
1 bDescriptorType 1 21h DFU FUNCTIONAL descriptor type
2 bmAttributes 1 Bit mask
DFU Attributes:
bit 7..3 : reserved
bit 2: device is able to communicate via USB after Manifestation phase
1 = yes, 0 = no, must see bus reset
bit 1: bitCanUpload : upload capable 1 = yes, 0 = no
bit 0: bitCanDnload : download capable 1 = yes, 0 = no
3 wDetachTimeOut 2 Number
Time in milliseconds that the device will wait after receipt of the
DFU_DETACH request.
If this time elapses without a USB reset, the device will terminate the
Reconfiguration phase and revert back to normal operation. This
represents the maximum time that the device can wait (depending on its
timers, ...). The Host may specify a shorter timeout in the DFU_DETACH
request.
5 wTransferSize 2 Number
Maximum number of bytes that the device can accept per control-write
transaction