USB4640 datasheet(35/64 Pages) SMSC

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High Speed Inter-Chip (HSIC) USB 2.0 Hub and Flash Media Controller

Datasheet

SMSC USB4640/USB4640i

Revision 1.0 (06-09-09)

DATASHEET

8.4.1.17

9Ah: USB BmAttribute (1 byte)

8.4.1.18

9Bh: USB MaxPower (1 byte)

BIT

NAME

DESCRIPTION

7:0

USB_BM_ATT

Self- or Bus-Power: Selects between self- and bus-powered operation.

The hub is either self-powered (draws less than 2 mA) or bus-powered

(limited to 100 mA maximum power prior to being configured by the host

controller).

When configured as a bus-powered device, the SMSC hub consumes less

than 100 mA of current prior to being configured. After configuration, the bus-

powered SMSC hub (along with all associated hub circuitry, any embedded

devices if part of a compound device, and 100 mA per externally available

downstream port) must consume no more than 500 mA of current. The

current consumption is system dependent, and the OEM must ensure that

the USB 2.0 Specification is not violated.

When configured as a self-powered device, <1 mA of current is consumed

and all ports are available, with each port being capable of sourcing 500 mA

of current.

80 = Bus-powered operation (default)

C0 = Self-powered operation

A0 = Bus-powered operation with remote wake-up

E0 = Self-powered operation with remote wake-up

BIT

NAME

DESCRIPTION

7:0

USB_MAX_PWR

USB Max Power per the USB 2.0 Specification. Do NOT set this value

greater than 100 mA.

USB4640 Datenblatt(PDF) 35 Page - SMSC Corporation