The difference between BOOT Loader and DFU mode??

[JPark.20]

I'm studying about the DFU mode to use this.

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So I'm looking for documents, but I'm confused whether the DFU mode and BOOT Loader are different or the same.

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I think,​

There is ​various ways to communicate with the MCU in Boot Loader state like UART, I2C, CAN, USB...

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And if i want to use USB to communicate with the MCU, i need to use USB in DFU mode.

So, in device manager, When i connected MCU using USB cable, PORT must be appear as a STM32 BOOT Loader.

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But, it sometimes appears as a bootloader or as a DFU.

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what is the difference between BOOT Loader and DFU mode??

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​I'm sorry if my words were awkward, I used a translator.

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[Uwe Bonnes]

You look for a difference where there is none. DFU mostly are for Boot loading, Bootloader often offer DFU. Bootloader may be provided by the chip itself, entered with reset and the right combination of boot pins and option bits, see AN2606. Or bootloaders are implemented as user code.

[Imen GH]

Hello @JPark.20​,

A DFU bootloader is a bootloader that supports updating the firmware of the device (called a Device Firmware Update, or short DFU). Through a DFU, you can update the application, the SoftDevice, or the current bootloader of your device.

The Application Note AN3156 (available on www.st.com) describes the USB DFU protocol used in STM32 microcontroller bootloader, detailing each supported command. So, I recommend you to have a look to: https://www.st.com/resource/en/application_note/cd00264379-usb-dfu-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf

And you can also refer to Application Note AN2606 “STM32 microcontroller system memory boot mode�?, which also contains more information about the USB hardware resources and requirements for the device bootloader:

https://www.st.com/content/ccc/resource/technical/document/application_note/b9/9b/16/3a/12/1e/40/0c/CD00167594.pdf/files/CD00167594.pdf/jcr:content/translations/en.CD00167594.pdf

Imen