I would like to couple the STEVAL-ISC004V1 (USB PD source) with the STEVAL-ISC005V1 (USB PD sink) like in this demonstration video https://youtu.be/Sld2pj-_ho0?t=100 My question is how you can choose which Vbus voltage level will be negotiated.

[JBaer.1]

In the video, it appears that the boards cycle automatically through the different PDO's (first the LED at the 9V PDO lights up, then the LED at the 15V PDO and so on. Is this default?

Let's say that I connect an electric razor to the 15V PDO at the sink board, how do I communicate then to the board that I want this PDO to be selected and the regulator on the source board has to output 15V (this is one of the default configurations)?