DFU

A USB Device Firmware Upgrade (DFU mode) device with two firmware partitions, demonstrating download, upload and manifestation.

What it does

Exposes a DFU interface with two alternate settings, one per simulated partition: alt 0 FLASH, alt 1 EEPROM.
Download (host to device): prints each received byte to stdout and immediately reports flashing complete.
Upload (device to host): returns a fixed string per partition (Hello world from TinyUSB DFU! - Partition 0/1), single block only.
Reports per-partition poll timeouts during download: 1 ms for FLASH (alt 0), 100 ms for EEPROM (alt 1).
Logs manifestation, abort and detach events.
Provides a BOS / Microsoft OS 2.0 descriptor so Windows binds the WinUSB driver.
LED blink rate indicates bus state (not mounted / mounted / suspended).

Interface	Class driver
0	DFU (two alternate settings)

Notable tusb_config.h settings:

#define CFG_TUD_DFU               1
#define CFG_TUD_DFU_XFER_BUFSIZE  (TUD_OPT_HIGH_SPEED ? 512 : 64)

CMake:

bash

mkdir build && cd build
cmake -DBOARD=raspberry_pi_pico ..
cmake --build .

Make:

bash

make BOARD=raspberry_pi_pico all

List the device in DFU mode:

bash

dfu-util -l

Download firmware to a partition (a text file works well for this demo):

bash

dfu-util -d cafe -a 0 -D firmware.bin    # partition 0 (FLASH)
dfu-util -d cafe -a 1 -D firmware.bin    # partition 1 (EEPROM)

Upload from a partition back to the host:

bash

dfu-util -d cafe -a 0 -U readback.bin
dfu-util -d cafe -a 1 -U readback.bin

Downloaded bytes are echoed on the device's stdout; uploads return the partition's fixed string.