Connecting USB HUB to STM32

[ISeed]

Hello,

I understand that many STM32 support USB OTG, so they can be USB hosts.

What if I want to connect more than one device? Can I connect a USB hub and control several devices at the same time?

[waclawek.jan]

Yes, but the USB host stack coming with Cube/CubeMX does not support hub(s). You would need to resort to 3rd party libraries, or write your own.

JW

[Pavel A.]

Segger's USBH library manual says that Synopsys controllers in F and L series have a bug with low-speed devices connected thru a external hub:

https://www.segger.com/downloads/emusb-host/UM10001 19.3.2.1

(show stopper for me because I use low-speed HID devices).

Segger's support states that at least some H series MCUs do not have this bug (I haven't tested).

Hope this helps.

-- pa

[ISeed]

Wow, ok. Thanks for the warning!

Low speed is 1.5 Mbit? So if I'm using a USB camera, we should be fine?

[Pavel A.]

> So if I'm using a USB camera, we should be fine?

If you also use Segger's or other good library with hub support - maybe.

ST's free "middleware" does not work with hubs.

-- pa

[ISeed]

This is really important. Thank you!

[PatrickF · Accepted solution]

Maybe a little bit out of you requirements, but please note that MPUs of STM32MP1 Series embed an USB high speed Host (named USBH) with 2 ports and PHY, and, if you want more, fully support USB Hub (soldered or external box) under Linux without any 3rd party license (as an example, there is already a 1 to 4 hub on STM32MP157C-DK2).

Btw, the provided USB camera demo on the discovery work through internal Hub.

[ISeed]

Thanks! I was actually thinking in that direction.

Where do you see the USB camera demo?

[PatrickF]

please have a look to https://wiki.st.com/stm32mpu/wiki/Getting_started/STM32MP1_boards/STM32MP157C-DK2/Let's_start/Use_the_demo_launcher

and https://www.youtube.com/watch?v=M-oodDBpETI

[ISeed]

May god bless you with many sons.