Accessing external storage on Nucleo

Question

There is 1.6 MB of external storage shows when we connect Nucleo to PC. Can we access that storage to save or read files from it from application i.e. in code? I haven't found any particular solution anywhere so asking here.

Answer 1

Except the "major" MCU for application, there is another MCU on the Nucleo board works as a programmer (ST-Link). This auxiliary MCU is connected to the application MCU with an UART for virtual com port, and a SWD for programming. That 1.6 MB of external storage you see on PC is emulated by this programmer MCU, and the firmware in this MCU has no simple way to be modified (suppose you still need it to act as a functional programmer and VCP). So the answer to your question is no simple way to do that, unless you are willing to sacrifice the programmer functionality of the auxiliary MCU and write a protocol to access the emulated storage on that MCU.

Answer 2

The mass storage device presented is not real, it is presented by the Nucleo bootloader/debugger interface chip as a simple drag-and-drop means of programming without additional software on the host PC. It is a means of programming the on-chip flash of the STM32 and is not external storage.