Rp

Rp

CC

Rds

Rds

Ra

Ra

Cable

DFP monitors for

connection

DFP monitors for

connection

UFP monitors for

connection

UFP monitors for

connection

Detect Valid

Connection

Establish USB

Power Method

USB Device

Enumeration

13

TPS25810-Q1

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SLVSD95 – NOVEMBER 2016

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Figure 11. Flow of DFP to UFP Configuration

7.1.3 Detecting a Connection

DFPs and DRPs fulfill the role of detecting a valid connection over USB Type-C. Figure 12 shows a DFP-to-UFP

connection made with Type-C cable. As shown in Figure 12, the detection concept is based on being able to

detect terminations in the product that has been attached. A pullup and pulldown termination model is used. A

pullup termination can be replaced by a current source.

•

In the DFP-UFP connection, the DFP monitors both CC pins for a voltage lower than the unterminated

voltage.

•

A UFP advertises Rd on both its CC pins (CC1 and CC2).

•

A powered cable advertises Ra on only one of the CC pins of the plug. Ra is used to inform the source to

•

An analog audio device advertises Ra on both CC pins of the plug, which identifies it as an analog audio

Figure 12. DFP-UFP Connection