Waking host with USB driver Topic is solved

[e_l_tang]

Is there a way to wake up the host during suspend? I did not find any function which could do this in the API.

[Giovanni]

Hi,

It is the host that wakes up the device if I remember well.

Giovanni

[e_l_tang]

Some classes of devices need to be able to wake up the host as well. For example a keyboard or mouse needs to wake up the host when the user provides input.

[Giovanni]

How is the host signaled?

Giovanni

[e_l_tang]

On an AVR the USB hardware does it when a bit is set in a register. I imagine that other chips don't do it much differently.

[Giovanni]

Moving this topic under "change request".

Giovanni

[e_l_tang]

For your reference, here is some example AVR code. Hope it helps.

[FXCoder]

One this topic...
We had a thread going that discussed the RWUSIG bit in the last posts.

The primary matter was RWUSIG being set by the USB driver instead of being cleared....
viewtopic.php?f=38&t=4076&start=10#p29927

In the case of an application level setting RWUSIG then the RWUSIG bit would need to be explicitly cleared by the driver (which it currently isn't - it is set instead).
If RWUSIG is set by the core (from L1 sleep state) then it is cleared automatically 50us later.

[Giovanni]

Hi,

I added a tentative usbWakeupHost() API to trunk, I have no way to test it, could you give a feedback?

I will back-port the change to 17.6.x if it is OK.

Giovanni

[e_l_tang]

I took a look at the code and I think the high level driver could be made more general. On AVR the software simply sets the bit and the hardware takes care of the rest. It is not necessary for it to wait or clear the bit.