USB5906 datasheet(33/64 Pages) MICROCHIP

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2016-2021 Microchip Technology Inc.

DS00002242E-page 34

USB5906

8.5

Remote Wakeup Indicator

The remote wakeup indicator feature uses

SUSP_IND as a side band signal to wake up the host when in USB 2.0 sus-

pend. This feature is enabled and disabled via the HUB_RESUME_INHIBIT configuration bit in the hub configuration

space register HUB_CFG_3. The only way to control the bit is by configuration EEPROM, SMBus or internal ROM

default setting. The state is only modified during a power on reset, or hardware reset. No dynamic reconfiguring of this

capability is possible.

When HUB_RESUME_INHIBIT = ‘0’, Normal Resume Behavior per the USB 2.0 specification

When HUB_RESUME_INHIBIT = ‘1’, Modified Resume Behavior is enabled

8.6

Port Control Interface

Port power and over-current sense share the same pin (

PRT_CTLx) for each port. These functions can be controlled

directly from the USB hub, or via the processor. Additionally, smart port controllers can be controlled via the I2C inter-

face.

The device can be configured into one of the two following port control modes:

•

Ganged Mode - A single GANG_PWR pin controls power and detects over-current events for all downstream

ports.

•

Individual Mode - Each port has an individual PRT_CTLx pin for independent port power control and over-current

detection.

Port connection in various modes are detailed in the following subsections.

8.6.1

PORT CONNECTION IN GANGED MODE

Ganged Mode is enabled via SMBus or OTP configuration.

GANG_PWR becomes the port control (PRTCTL) pin for all

downstream ports when the hub is configured for ganged port power control mode. All port power controllers should be

controlled from this pin when the hub is configured for ganged port power mode. While in this mode of operation, an

over-current event on any single downstream port will cause all downstream ports to be flagged for over-current.

8.6.2

PORT CONNECTION IN INDIVIDUAL MODE

8.6.2.1

Port Power Control using USB Power Switch

Individual mode is the default mode of operation. When operating in individual mode, the device will have one port power

control and over-current sense pin for each downstream port. When disabling port power, the driver will actively drive a

'0'. To avoid unnecessary power dissipation, the pull-up resistor will be disabled at that time. When port power is

enabled, it will disable the output driver and enable the pull-up resistor, making it an open drain output. If there is an

over-current situation, the USB Power Switch will assert the open drain OCS signal. The Schmidt trigger input will rec-

ognize that as a low. The open drain output does not interfere. The over-current sense filter handles the transient con-

ditions such as low voltage while the device is powering up.

Note:

The

SUSP_IND signal only indicates the USB2.0 state.

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