STM32H7 Host with multiple devices.

[LGall]

Hi,

I would like to use USB HOST to use multiple devices. We would like use the following configuration :

1 host and 15 devices max with 5 hub between them

So I am using STM32H747 as Host and I saw the following sentence in Reference manual :

"Up to 16 host channels (pipes): each channel is dynamically reconfigurable to allocate any type of USB transfer."

So if I understand well I can only use 8 devices max (8 endpoint IN + 8 endpoint OUT) and probably 7 because 1 endpoint reserved for the endpoint 0 (configuration)

Am I right ?

Is my configuration is possible ?

Thanks a lot for answers.

Best regards,

Logan

[berendi]

AFAIK the USB host software provided by ST does not support hubs at all. Of course it should be possible to write it yourself, but it won't be trivial.

Why do you need 5 hubs? Physical distance?

[LGall]

Yeah for the distance purpose and wires optimization.

I saw some libraries are able to manage HUBs but if STM32 has HW limitation already (endpoint limited to 16). It is not necessary to test them.

[VAlec.1]

I haven't seen the H Series. And for the F Series, you can use all 16 channels, you can also reassign channels.

You can use two HS and FS stacks in host mode, it works.

If the FS hub is connected to the usb port and the LS hid is connected to the hub, problems are likely to occur.