Re: Wake on USB event

On 01-Feb-25 8:36 am, Don Y wrote:

On 1/31/2025 9:22 AM, Sylvia Else wrote:

It also seems like Windows only leaves USB ports powered up
during sleep *if* they were active while the machine was awake (?).

>
It appears to me that the device drives a 'K' state onto the data lines for between 1 and 15ms. The 'K' state is the opposite of the idle state.

 Said another way, does the exchange contain "data" (a keystroke) or
is it purely for notification?

If I appear to be double posting, it's because some of my postings seem to be vanishing.
On my reading of the spec, it just swaps the data line levels for a period, and then swaps them back. I wouldn't expect any data transfer, because USB devices do not spontaneously send data, they respond only when polled.
I suspect it's going to come down to the voltage levels on the data+ and data- lines. Data+ should stay high (above 3V), and data- should stay low. Time to build that USB breakout box.
Sylvia.