Board with some features similar to STLink

[Paul1]

We have a new project and would like it to have some features similar to the STM32 on an STLink:

a) Emulate a Thumbdrive using MCU FLASH and/or an external serial FLASH IC. The files should be accessible by both the STM32 and any PC connected to the USB on the board for holding configuration and logs.

b) Drag and drop self programming (This is a variation of what the STLink does to attached boards, and the STLink firmware upgrade process).

c) VCP, a virtual UART for diagnostics.

d) Bonus if some security method is included.

Can anyone recommend a starting point?

I've tried some examples in MX, some worked, some didn't.

• We haven't successfully emulated a thumbdrive. In MX Example selector I couldn't get Ux_Device_MSC examples to work on any of our ST Demo hardware (either L4R9 Discovery or F769 Discovery, also some Nucleos).
• We have external thumbdrive file system working on H743 USB-Host, but that isn't what we need here.
• We have VCP working over D+/D- on a USBC connector.
• Initial target is STM32L476, and later a lower cost device.

Not sure where to start with combining them to all work in one STM32 on a single USB Device connection to a PC, maybe someone has already done something like this? I'm happy to write up the results for others if we can get it working.

Thank you for any help.

Paul

[Javier1 · Accepted solution]

a) youre tring to implement a USB mass storage (MSC) device.

b) youre tring to implement a USB mass storage (MSC) bootloader.

c) in addition to the mass storage (MSC) bootloader you want a CDC USB device, so youre walking into the USB composite devices realm.

d) cool

This sounds like something that has been done 100times, is it easy? no

to accomodate the filesystem and enough space for bootloading from filesystem and storing sensor data you will probably need all the FLASH memory you can find or a SD card

something like this?

[Paul1]

Javier,

Thank you for the link, USB Composite Device sounds like just what we need. I'll definitely give this a try.

Paul

[Paul1]

Did get TinyUSB running on an STM32L476G-Discovery, using

• jadczakoff/Test_USB_Tiny_L4 (github.com).
• with dwc2 mod from CDC + MSC STM32L4 · Discussion #1736 · hathach/tinyusb (github.com)
• This example gives me MSC and CDC.

Will play more when time allows.

Paul