Table 7-4. USB Type-C States According to TUSB320 Functional Modes (continued)

MODES

GENERAL BEHAVIOR

PORT PIN

STATES(1)

Shutdown

VDD available.

EN_N pin high.

UFP/DRP/DFP

Default device state to UFP/SNK with Rd.

(1)

Required; not in sequential order.

7.4.1 Unattached Mode

Unattached mode is the primary mode of operation for the TUSB320 device, because a USB port can be

unattached for a lengthy period of time. In unattached mode, VDD is available, and all IOs and I2C are

operational. After the TUSB320 device is powered up, the part enters unattached mode until a successful attach

has been determined. Initially, right after power up, the TUSB320 device comes up as an Unattached.SNK. The

TUSB320 device checks the PORT pin and operates according to the mode configuration. The TUSB320 device

toggles between the UFP and the DFP if configured as a DRP. In unattached mode, I2C can be used to change

the mode configuration or port role if the board configuration of the PORT pin is not the desired mode. Writing

to the I2C MODE_SELECT register can override the PORT pin only in unattached mode. The PORT pin is only

sampled at reset or power up. I2C must be used after reset to change the device mode configuration.

7.4.2 Active Mode

Active mode is defined as the port being attached. In active mode, all GPIOs are operational, and I2C is read /

write (R/W). When in active mode, the TUSB320 device communicates to the AP that the USB port is attached.

This happens through the ID pin if TUSB320 is configured as a DFP or DRP connect as source. If TUSB320

is configured as an UFP or a DRP connected as a sink, the OUT1/OUT2 and INT_N/OUT3 pins are used. The

TUSB320 device exits active mode under the following conditions:

• Cable unplug

• VBUS removal if attached as an UFP

• Dead battery; system battery or supply is removed

• EN_N pin floated or pulled high

During active mode, I2C cannot be used to change the mode configuration. This can only be done if TUSB320 is

in an unattached state.

7.4.3 Dead Battery Mode

During dead battery mode, VDD is not available. CC pins always default to pulldown resistors in dead battery

mode. Dead battery mode means:

• TUSB320 in UFP with 5.1-kΩ ± 20% Rd; cable connected and providing charge

• TUSB320 in UFP with 5.1-kΩ ± 20% Rd; nothing connected (application could be off or have a discharged

battery)

Upon exiting dead battery mode (VDD is active), the software must perform the following sequence in order for

Rp to be presented on both CC pins:

1. Write a 0x04 to I2C address 0x45.

2. Wait 30ms.

3. Write a 0x00 to I2C address 0x45.

Between steps 1 and 3, the status flags will be set. The software must ignore these flags when performing the

three steps.

Note

When VDD is off, the TUSB320 non-failsafe pins ( VBUS_DET, ADDR, PORT, ID, OUT[3:1] pins)

could back-drive the TUSB320 device if not handled properly. When necessary to pull these pins up,

it is recommended to pullup PORT, ADDR, INT_N/OUT3, and ID to the device’s VDD supply. The

VBUS_DET must be pulled up to VBUS through a 900-kΩ resistor.

TUSB320, TUSB320I

SLLSEN9F – MAY 2015 – REVISED MARCH 2022

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