The GUI will have a button to identify a particular PD Buddy Sink, in
case several are connected to the computer at once. The button will
cause the LED to blink quickly for a couple seconds, then go back to
normal. To allow this, I added a new LED blink mode (FAST_BLINK_SLOW)
that causes 8 fast blinks, then returns to SLOW_BLINK mode. A new
"identify" command triggers this LED mode.
There are still a few things that the standard says we Shall do and we
don't, but it Works For Me™. I haven't implemented anything with
regards to GiveBack support, but that doesn't matter just yet. Our
handling of VDMs isn't quite right either. Anyway, it successfully
negotiates with so-called Split PDO power supplies, which is more than I
can say about some commercial products.