USB PD requires communication over the CC pins via setting different resistor values and checking them at specific times in the hand shaking process. The commun

USB PD requires communication over the CC pins via setting different resistor values and checking them at specific times in the hand shaking process. The communication in the latest spec is supposed to happen at about 300kbs using a specific protocol on a specific CC line. There have been multiple specs since about 2011, some of which used communication over the VBUS line using BFSK, which has since been deprecated. This adds to the confusion.