FUSB302TMPX datasheet(9/36 Pages) ONSEMI

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Manual Dual-Role Detection and Configuration

The Type-C specification allows ports to be both a

device and a host depending on what type of port has

attached. This functionality is similar to USB OTG ports

with the current USB connectors and is called a dual-

role port. The FUSB302T can be used to implement a

dual-role port. A Type-C dual role port toggles between

presenting as a Type-C device and a Type-C host. The

host software controls the toggle time and configuration

of the FUSB302T in each state as shown in Figure 9.

Figure 9.

DRP Software Flow

BMC Power Delivery

The Type-C connector allows USB Power Delivery (PD)

to be communicated over the connected CC pin

between two ports. The communication method is the

BMC Power Delivery protocol and is used for many

different reasons with the Type-C connector. Possible

uses are outlined below.

 Negotiating and controlling charging power levels

 Alternative Interfaces such as MHL, Display Port

 Vendor specific interfaces for use with custom

docks or accessories

 Role swap for dual-role ports that want to switch

who is the host or device

 Communication with USB3.1 full featured cables

The FUSB302T integrates a thin BMC PD client which

includes the BMC physical layer and packet FIFOs (48

bytes for transmit and 80 bytes for receive) which allows

packets to be sent and received by the host software

through I2C accesses. The FUSB302T allows host

software to implement all features of USB BMC PD

through writes and reads of the FIFO and control of the

FUSB302T physical interface.

The FUSB302T uses tokens to control the transmission

of BMC PD packets. These tokens are written to the

transmit FIFO and control how the packet is transmitted

on the CC pin. The tokens are designed to be flexible

and support all aspects of the USB PD specification.

The FUSB302T additionally enables control of the BMC

transmitter through tokens. The transmitter can be

enabled or disabled by specific token writes which allow

faster packet processing by burst writing the FIFO with

all the information required to transmit a packet.

The FUSB302T receiver stores the received data and

the received CRC in the receive FIFO when a valid

packet is received on the CC pin. The BMC receiver

automatically enables the internal oscillator when an

Activity is sensed on the CC pin and load to the FIFO

when a packet is received. The I_ACTIVITY and

I_CRC_CHK interrupts alert the host software that a

valid packet was received.

Disabled:

FUSB302T in low power

mode looking for an attach

Unattached.UFP:

Host software enables

FUSB302T pull-downs

and measure block to

detect attach

FUSB302T I_WAKE

interrupt alerts host

software that something

has attached.

Attached.UFP

Host software uses FUSB302T

comparators and DAC to

determine attach orientation and

port type

FUSB302T I_VBUSOK interrupt

alerts host software that an attach

has occurred

FUSB302T I_VBUSOK interrupt

alerts host software that a detach has

occurred

Host software enables

FUSB302T low power

Disabled state

Unattached.DFP:

Host software enables

FUSB302T pull-ups and

measure block to detect

attach

Attached.DFP

Host software configures

FUSB302T based on insertion

orientation and enables VBUS

and VCONN

Host software toggle

expires

Host software utilizes I_COMP and

I_BC_LVL interrupts to determine an

attach

FUSB302T I_COMP interrupt alerts

host software that a detach has

occurred

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