For a detailed description of the Type-C spec refer to the USB-IF website to download the latest released version. Some of the basic concepts of the Type-C spec that pertains to understanding the operation of the TPS25820/21 (a Downward Facing Port, DFP device) are described as follows.
USB Type-C removes the need for different plug and receptacle types for host and device functionality. The Type-C receptacle replaces both Type-A and Type-B receptacles since the Type-C cable is plug-able in either direction between host and device. A host-to-device logical relationship is maintained via the configuration channel (CC). Optionally hosts and devices can be either providers or consumers of power when USB PD communication is used to swap roles.
All USB Type-C ports operate in one of below three data modes:
Valid Source-to-Sink connections:
|POWER ROLES||SOURCE ONLY||SINK ONLY||DUAL ROLE POWER (DRP)|
|Source Only||Not allowed||Allowed||Allowed|
|Sink Only||Allowed||Not allowed||Allowed|
|Dual Role Power (DRP)||Allowed||Allowed||Allowed|