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DS000002248A-page 13

USB2502

5.1.1.7

Current Sensing

Selects current sensing as all ports ganged, or none.

This field can be set by the OEM using either the SMBus or EEPROM interface options.When using the internal default

option, the SELF_PWR pin determines if current sensing will be ganged, or none (ganged if self-powered, none if bus-

powered).

5.1.1.8

Compound Device

Allows the OEM to indicate that the Hub is part of a compound (see the USB Specification for definition) device. The

applicable port(s) must also be defined as having a “Non-Removable Device”.

This field is set by the OEM using either the SMBus or EEPROM interface options.

Note: When configured via strapping options, declaring a port as non-removable automatically causes the hub controller

to report that it is part of a compound device.

5.1.1.9

Non-Removable Device

Informs the Host if one of the active ports has a permanent device that is undetachable from the Hub. (Note: The device

must provide its own descriptor data.)

This field is set by the OEM using either the SMBus or EEPROM interface options. When using the internal default

option, the NON_REM[1:0] pins will designate the appropriate ports as being non-removable.

5.1.1.10

Self-Powered Port DISABLE

During Self-Powered operation, this selects the ports which will be permanently disabled, and are not available to be

enabled or enumerated by a Host Controller. The disabled ports must be in decreasing order starting with port 2.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.11

Bus-Powered Port DISABLE

During Bus-Powered operation, this selects the ports which will be permanently disabled, and are not available to be

enabled or enumerated by a Host Controller. The disabled ports must be in decreasing order starting with port 2.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.12

Dynamic Power

Controls the ability of the 2-Port Hub to automatically change from Self-Powered operation to Bus-Powered operation

if the local power source is removed or is unavailable (and from Bus-Powered to Self-Powered if the local power source

is restored). {Note: If the local power source is available, the 2-port Hub will always switch to Self-Powered operation.}

When Dynamic Power switching is enabled, the Hub detects the availability of a local power source by monitoring the

external SELF_PWR pin. If the Hub detects a change in power source availability, the Hub immediately disconnects and

removes power from all downstream devices and disconnects the upstream port. The Hub will then re-attach to the

upstream port as either a Bus-Powered Hub (if local-power in unavailable) or a Self-Powered Hub (if local power is avail-

able).

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.13

Over-Current Timer

The time delay (in 2ms increments) for an over-current condition to persist before it is reported to the Host.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.14

Self-Powered Max Power

When in Self-Powered configuration, Sets value in 2mA increments.

This field is set by the OEM using either the SMBus or EEPROM interface options.

5.1.1.15

Bus-Powered Max Power

When in Bus-Powered configuration, Sets value in 2mA increments.

This field is set by the OEM using either the SMBus or EEPROM interface options.