DocID017068 Rev 4

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AN3156

DFU_DNLOAD request commands

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The allowed locations for address pointer values are valid memory addresses (see note) in

the internal Flash memory, embedded RAM, system memory and option bytes.

Note:

1

Refer to Section 4: DFU_UPLOAD request commands for more details about the valid

memory addresses for the device you are using.

2

The Set Address Pointer command is allowed and executed when the Flash Read

Protection is enabled or disabled.

Figure 8. Set Address Pointer command: Device side

5.3

Erase command

The Erase command is selected when wValue = 0 and the first byte of the buffer sent by the

host is 0x41. The buffer length may be 5 bytes (the four remaining bytes are the address

bytes, LSB first) for the page erase operation or only 1 byte (only the command byte) for the

Mass erase operation.

The host sends a DFU_DNLOAD request with the above parameters to erase one page of

the internal Flash memory or to perform a mass erase of this Flash memory.

The device receives the bytes as follows (page erase):

Or, if a 1-byte command is received:

The STM32 receives the bytes as follows (Mass Erase):

After sending an Erase command, the host has to send a DFU_GETSTATUS request.

Byte 1:

0x41

- Erase command

Byte 2:

A[7:0]

- LSB of the page address

Byte 3:

A[15:8]

- Second byte of the page address

Byte 4:

A[22:16] - Third byte of the page address

Byte 4:

A[31:23] - MSB of the page address

Byte 1:

0x41

- Erase command