Table 7-1. Supported Features for the TUSB320 Device by Mode

PORT PIN

HIGH

(DFP ONLY)

LOW

(UFP ONLY)

NC

(DRP)

SUPPORTED

FEATURES

Port attach and

detach

Yes

Yes

Yes

Cable orientation

(through I2C)

Yes

Yes

Yes

Current

advertisement

Yes

—

Yes (DFP)

Current detection

—

Yes

Yes (UFP)

Accessory modes

(audio and debug)

Yes

—

Yes

Active cable detection

Yes

—

Yes (DFP)

I2C / GPIO

Yes

Yes

Yes

Legacy cables

Yes

Yes

Yes

VBUS detection

—

Yes

Yes (UFP)

7.3.1.1 Downstream Facing Port (DFP) – Source

The TUSB320 device can be configured as a DFP only by pulling the PORT pin high through a resistance to

VDD. In DFP mode, the TUSB320 device constantly presents Rps on both CC. In DFP mode, the TUSB320

device initially advertises default USB Type-C current. The Type-C current can be adjusted through I2C if the

system needs to increase the amount advertised. The TUSB320 device adjusts the Rps to match the desired

Type-C current advertisement. In GPIO mode, the TUSB320 device only advertises default Type-C current.

When configured as a DFP, the TUSB320 can operate with older USB Type-C 1.0 devices except for a USB

Type-C 1.0 DRP device. The TUSB320 can not operate with a USB Type-C 1.0 DRP device. This limitation is a

result of a backwards compatibility problem between USB Type-C 1.1 DFP and a USB Type-C 1.0 DRP.

7.3.1.2 Upstream Facing Port (UFP) – Sink

The TUSB320 device can be configured as an UFP only by pulling the PORT pin low to GND. In UFP mode, the

TUSB320 device constantly presents pulldown resistors (Rd) on both CC pins. The TUSB320 device monitors

the CC pins for the voltage level corresponding to the Type-C mode current advertisement by the connected

DFP. The TUSB320 device debounces the CC pins and wait for VBUS detection before successfully attaching. As

an UFP, the TUSB320 device detects and communicates the advertised current level of the DFP to the system

through the OUT1 and OUT2 GPIOs (if in GPIO mode) or through the I2C CURRENT_MODE_DETECT register

one time in the Attached.SNK state.

After initial connection, the advertised current by the connected DFP could change due to changes in its system

power resource. For example, a DFP could advertise high current on initial connection but then decide to reduce

to default current because user removed external power adapter from their notebook. Because the TUSB320

will only advertise on OUT1 and OUT2 the initial advertised current, it is recommend to monitor the advertised

current through the TUSB320’s I2C interface from the CURRENT_MODE_DETECT register. System software

must periodically perform a I2C_SOFT_RESET in order for the CURRENT_MODE_DETECT register to be

updated based on the state of the CC pins.

7.3.1.3 Dual Role Port (DRP)

The TUSB320 device can be configured to operate as a DRP when the PORT pin is left floated on the PCB. In

DRP mode, the TUSB320 device toggles between operating as a DFP and an UFP. When functioning as a DFP

in DRP mode, the TUSB320 device complies with all operations as defined for a DFP according to the Type-C

specification. When presenting as an UFP in DRP mode, the TUSB320 device operates as defined for an UFP

according to the Type-C specification.

www.ti.com

TUSB320, TUSB320I

SLLSEN9F – MAY 2015 – REVISED MARCH 2022

Copyright © 2022 Texas Instruments Incorporated

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