Re: [libusb] Loosing connection to USB devices.

[David G. <dav...@gm...>]

When the USB host is running, it normally broadcasts a Start of Frame (SOF)
packet every millisecond (or maybe at a different rate depending on what
USB speed you are using).  This should signal to all the devices that the
bus is active and they need to stay awake and be ready to respond to
packets they receive.  You might try using a USB protocol analyzer like the
Beagle from Total Phase to see if those SOF packets are actually getting
sent.  It's also possible that you are seeing a bug in the latest version
of the inverter firmware.

--David Grayson


On Wed, Oct 12, 2022 at 5:56 AM Jaco <ja...@jd...> wrote:

> Hi all.
>
>
>
> I am not sure if this is a libusb issue. I do not think so. I just want to
> ask a question as I am not a USB guru.
>
> I have been using libusb for the last 3 years to communicate with solar
> inverters from the raspberry pi SBC.
>
> All is working 100%. The issue I have is that I started to see that the
> new inverters will shut down their USB port after a while.
>
>
>
> So my question is this. Is there some sort of hardware handshake / flow
> control like with serial to tell the USB device not to go into sleep mode?
>
> I have not needed it up till now but we are now seeing that a lot of new
> devices will go into “sleep” mode. Unplugging the USB device does not help.
>
> So I am not sure if this is a hardware issue to address with the inverter
> manufacturer or what is going on.
>
>
>
> Kind Regards.
>
>
>
>
>
>
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