Fysetc S6: use PIO DFU with proper settings

[trouch]

Requirements

• Fysetc S6 Board
• Press the BOOT0 button while turning on printer/board to enter DFU
• Upload using PIO

It uses PIO / stm32duino bundled dfu-util, so it should work across systems.

Description

Fysetc S6 doesn't have serial bootloader. It has SD bootloader and DFU instead.

Benefits

Allows to flash Fysetc S6 from PIO directly.

Related Issues

[thinkyhead]

This is a good thing to have. Is the serial option something we want to preserve for some, or is this option essentially universal?

[trouch]

AFAIK all STM32 has non erasable DFU bootloader.
However, it depends on the actual board USB design.
When there is an USB-Serial bridge, we can't use DFU obviously.
Like with the Fysetc Cheetah (STM32F103) which requires stm32flash Serial flashing method.