7.3.2 Type-C Current Mode

When a valid cable detection and attach have been completed, the DFP has the option to advertise the level of

Type-C current an UFP can sink. The default current advertisement for the TUSB320 device is 500 mA (for USB

2.0) or 900 mA (for USB 3.1). If a higher level of current is available, the I2C registers can be written to provide

medium current at 1.5 A or high current at 3 A. When the CURRENT_MODE_ADVERTISE register has been

written to advertise higher than default current, the DFP adjusts the Rps for the specified current level. If a DFP

advertises 3 A, it ensures that the VDD of the TUSB320 device is 3.5 V or greater. Table 7-2 lists the Type-C

current advertisements in GPIO an I2C modes.

Table 7-2. Type-C Current Advertisement for GPIO and I2C Modes

TYPE-C CURRENT

GPIO MODE (ADDR PIN IN NC)

I2C MODE (ADDR PIN H, L)

UFP (PORT PIN L)

DFP (PORT PIN H)

UFP

DFP

Default

500 mA (USB

2.0)

900 mA (USB

3.1)

Current mode detected

and output through

OUT1 / OUT2

Only advertisement

Current mode detected

and read through I2C

register

I2C register default is 500

or 900 mA

Medium – 1.5 A

N/A

Advertisement selected

through writing I2C register

High – 3 A

7.3.3 Accessory Support

The TUSB320 device supports audio and debug accessories in DFP mode and DRP mode. Audio and debug

accessory support is provided through reading of I2C registers. Audio accessory is also supported through GPIO

mode with INT_N/OUT3 pin (audio accessory is detected when INT_N/OUT3 pin is low).

7.3.3.1 Audio Accessory

Audio accessory mode is supported through two types of adapters. First, the passive audio adapter can be used

to convert the Type-C connector into an audio port. To effectively detect the passive audio adapter, the TUSB320

device must detect a resistance < Ra on both of the CC pins.

Secondly, a charge through audio adapter may be used. The primary difference between a passive and charge

through adapter is that the charge through adapter supplies 500 mA of current over VBUS. The charge through

adapter contains a receptacle and a plug. The plug acts as a DFP and supply VBUS when the plug detects a

connection.

When the TUSB320 device is configured in GPIO mode, OUT3 pin determines if an audio accessory is

connected. When an audio accessory is detected, the OUT3 pin is pulled low.

7.3.3.2 Debug Accessory

Debug is an additional state supported by USB Type-C. The specification does not define a specific user

scenario for this state, but it is important because the end user could use debug accessory mode to enter a test

state for production specific to the application. Charge through debug accessory is not supported by TUSB320

when in DRP or UFP mode.

7.3.4 I2C and GPIO Control

The TUSB320 device can be configured for I2C communication or GPIO outputs using the ADDR pin. The ADDR

pin is a tri-level control pin. When the ADDR pin is left floating (NC), the TUSB320 device is in GPIO output

mode. When the ADDR pin is pulled high or pulled low, the TUSB320 device is in I2C mode.

All outputs for the TUSB320 device are open drain configuration.

The OUT1 and OUT2 pins are used to output the Type-C current mode when in GPIO mode. Additionally, the

OUT3 pin is used to communicate the audio accessory mode in GPIO mode. Table 7-3 lists the output pin

settings. See the Pin Functions table for more information.

TUSB320, TUSB320I

SLLSEN9F – MAY 2015 – REVISED MARCH 2022

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