AT89C51SND1_06 ATMEL [ATMEL Corporation], AT89C51SND1_06 Datasheet - Page 19

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

Figure 5. Example of Firmware Download Zero Length DFU_DNLOAD Request
Answers from
Bootloader
Reading the Flash
First Request from Host
4254C–MP3–03/06
SETUP
OUT
OUT
OUT
OUT
IN
The Host sends a DFU_DNLOAD request with the wLength field cleared to 0 to the device to
indicate that it has completed transferring the firmware image file. This is the final payload
packet of a download operation.
This operation should be preceded by a Long Jump address specification using the correspond-
ing Flash command.
After each program request, the Host can request the device state and status by sending a
DFU_GETSTATUS message.
If the device status indicates an error, the host can send a DFU_CLRSTATUS request to the
device.
The flow described below allows the user to read data in the Flash memory. A blank check com-
mand on the Flash memory is possible with this flow.
This operation is performed in 2 steps:
1. DFU_DNLOAD request with the read command (6 bytes)
2. DFU_UPLOAD request which correspond to the immediate previous command.
The Host sends a DFU Download request with a Display command in the data field.
DFU_DNLOAD
Prog_Start + (EP0 FIFO length - 6) x 00h
X offset bytes + Firmware Packet 1
Firmware Packet 2
Firmware Packet n + DFU suffix
ZLP
SETUP
OUT
IN
DFU_DNLOAD
Display_Data (6 bytes)
ZLP
AT89C51SND1
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