Hi Guys, I'm looking at STM32L475VET6 to use as OTG Host for USB Flash drive and usb barcode reader.

[Tom]

Hi Guys, I'm looking at STM32L475VET6 to use as OTG Host for USB Flash drive and usb barcode reader. Since USB hub is not supported by STM32L4 what is the best way to multiplex the D+/- pins of the MCU? I will always have the barcode reader connected and usb flash drive will be connected occasionally. I will have 2 separate USB connectors on the PCB, one for the reader and another for the flash drive.

thanks and regards

Tom

[Pavel A.]

Are you sure that L4 does not support hubs? The ST USB "middleware" does not, but have you checked other software vendors such as Segger?

I have hub working (kind of, as experiment) on STM32F446, by heavily hacking the ST drivers and some example found on github.

If L4 is similar to, or better than F4, it should work too.

-- pa

[Tom]

Hi Pavel,

Thanks for the tip, you are right Segger has a lib for this but for 4000Euro I would be glad to hack it myself :)

I found TC7USB40FT USB multiplexer, it's cheap but I'm not sure how the enumeration will work while switching between slaves.

I also found STMPS2242MTR double power supply for usb slaves which I will use to turn off the slaves while switchin D+/- lines.

I hope this works!

Best regards

Tom