H7 USB devices Errata

[matt-crc]

Hello, I would like to get more info on Errata ES0392 Rev 13 - section 2.25.3:

the errata states:

I'm confused with the wording of this errata.  Can someone from ST describe the meaning of this errata?

I currently have USB0 connected to the USB Hub directly, and USB0 is configured as Host Only - High Speed:

When I saw this errata, I uploaded a patch to the USB-Hub and instructed it to do speed conversion on the hub before transmitting the data to the STM processor.  I'm able to connect to all the devices attached to the hub (mouse, keyb, storage) and it seems relatively reliable.

However, the problem that I'm having is that the USB Hub goes offline periodically.  When I probe the Hub it doesn't like the signals  from the STM host.  When I checked on the scope, it seems the signals are out of spec.  If I look at the STM32H743 data sheet, it states:

It appears that instead of using these dedicated USB drivers, it is using the standard GPIO drivers as shown in CubeMX.  I came to that conclusion because if I change the pin driver setting in CubeMX you can see the change on the USB lines.

So my question is:  Is there a register internal to the STM32H743 that I have to program to enable these low impedance drivers?

As for the state machine inside the STM hanging, I don't think I have encountered it so far.  I can detect that the HUB went offline, and then I can send a command to the hub to re-initialize and everything is back up and running.

[FBL]

Hi @matt-crc 

No workaround available for this product unfortunately. For example in STM32H7RS, this issue is fixed in the controller. Increasing impedance drivers is not a viable workaround for all cases so we don't recommend it. 

[matt-crc]

Hi @FBL 

I'm not looking for a work around, I'm trying to understand a few things...

First, I need to clarify some terminology here...  To me - 

HS (high speed) = 480Mb and can only be achieved by using an external phy  (not our case)

FS (Full speed) = 12Mb and will use the internal embedded phy (our case)

Slow speed = 1.5mb, usually associated with USB 1 / USB 1.1 (not our case)

So my questions are:

1- If I use the device in FS mode/speed ONLY, does this problem exist?  It is not clear from the wording in your Errata.

2- There appears to be a drive issue with the device.  We will have to do additional testing on the lines

3- you mentioned the STM32H7RS family.  I can't see these parts under distribution.

a) are the available yet?

b) are they pin compatible to the H7 family?

thanks

[Pavel A.]

@FBL It is great that this errata is resolved for STM32H7R/S. Is it resolved also for newer "normal" H7's, such as H72/73 ?