USB2503 datasheet(16/43 Pages) SMSC

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Integrated USB 2.0 Compatible 3-Port Hub

Datasheet

Revision 2.3 (08-27-07)

SMSC USB2503/USB2503A

DATASHEET

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.

5.1.1.13

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 contiguous,

and must be in decreasing order starting with port 3.

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

internal default option, the PRT_DIS0 pin will disable the appropriate ports.

5.1.1.14

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 contiguous,

and must be in decreasing order starting with port 3.

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

internal default option, the PRT_DIS0 pin will disable the appropriate ports.

5.1.1.15

Dynamic Power

Controls the ability of the 3-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

3-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 available).