3

General description

3.1

CC interface

The STUSB1702 controls the connection to the configuration channel (CC) pins, CC1 and CC2, through two main

blocks: the CC line interface block and the CC control logic block.

The CC line interface block is used to:

•

Configure termination mode on the CC pins relative to the power mode supported i.e. pull-up for source

power role

•

Monitor the CC pin voltage values relative to the attachment detection thresholds

•

Configure VCONN on the unconnected CC pin when required

•

Protect the CC pins against overvoltage

The CC control logic block is used to:

•

Execute the Type-C FSM relative to the Type-C power mode supported

•

Determine the electrical state for each CC pin relative to the detected thresholds

•

Evaluate the conditions relative to the CC pin states and the VBUS voltage value to transition from one state

to another in the Type-C FSM

•

Detect and establish a valid source-to-sink connection

•

Determine the attached device mode

•

Determine cable orientation to allow external routing of the USB data

•

Manage VBUS power capability: USB default, Type-C medium or Type-C high current mode

•

Handle hardware faults

The CC control logic block implements the Type-C FSMs corresponding to the following Type-C power modes:

•

Source power role with accessory support

The default Type-C power mode is selected through NVM programming (see Section 6 Start-up configuration)

and can be changed by software during operation through the I²C interface.

3.2

BMC interface

Figure 3. BMC interface

3.2.1

BMC interface behavior

When a connection is established on the STUSB1702 (any attached state), the CC line used for connection is

also internally connected to BMC block which allows the communication on this line.

The CC line is primary managed by CC control logic. BMC communication on the CC line must not interact with

this control logic, as driving times of the line are short and are related to denounce times of the CC logic.

STUSB1702

General description

DS12664 - Rev 1

page 7/38