USB 2.0 Hi-Speed 2-Port Hub Controller

Datasheet

4.2.1.7Register 06h: CONFIG_BYTE_1

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7

SELF_BUS_PWR

Self or Bus Power: Selects between Self- and Bus-Powered operation.

 

 

The Hub is either Self-Powered (draws less than 2mA of upstream bus

 

 

power) or Bus-Powered (limited to a 100mA maximum of upstream power

 

 

prior to being configured by the host controller).

 

 

When configured as a Bus-Powered device, the SMSC Hub consumes less

 

 

than 100mA 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 100mA per externally available

 

 

downstream port) must consume no more than 500mA of upstream VBUS

 

 

current. The current consumption is system dependent, and the OEM must

 

 

ensure that the USB 2.0 specifications are not violated.

 

 

When configured as a Self-Powered device, <1mA of upstream VBUS

 

 

current is consumed and all ports are available, with each port being capable

 

 

of sourcing 500mA of current.

 

 

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

 

 

options.

 

 

Please see the description under Dynamic Power for the self/bus power

 

 

functionality when dynamic power switching is enabled.

 

 

0 = Bus-Powered operation

 

 

1 = Self-Powered operation

 

 

Note: If Dynamic Power Switching is enabled, this bit is ignored and the

 

 

LOCAL_PWR pin is used to determine if the hub is operating from self or

 

 

bus power.

 

 

 

6

Reserved

Reserved

 

 

 

5

HS_DISABLE

High Speed Disable: Disables the capability to attach as either a High/Full-

 

 

speed device, and forces attachment as Full-speed only (i.e. no Hi-Speed

 

 

support).

 

 

0 = High-/Full-Speed

 

 

1 = Full-Speed-Only (Hi-Speed disabled!)

 

 

 

4

Reserved

Reserved

 

 

 

3

EOP_DISABLE

EOP Disable: Disables EOP generation of EOF1 when in Full-Speed mode.

 

 

During FS operation only, this permits the Hub to send EOP if no

 

 

downstream traffic is detected at EOF1. See Section 11.3.1 of the USB 2.0

 

 

Specification for additional details. Note: generation of an EOP at the EOF1

 

 

point may prevent a Host controller (operating in FS mode) from placing the

 

 

USB bus in suspend.

 

 

0 = EOP generation is normal

 

 

1 = EOP generation is disabled

 

 

 

2:1

CURRENT_SNS

Over Current Sense: Selects current sensing on a port-by-port basis, all

 

 

ports ganged, or none (only for bus-powered hubs). The ability to support

 

 

current sensing on a port or ganged basis is hardware implementation

 

 

dependent.

 

 

00 = Ganged sensing (all ports together)

 

 

01 = Individual port-by-port

 

 

1x = Over current sensing not supported (must only be used with Bus-

 

 

Powered configurations!)

 

 

 

Revision 1.96 (07-11-08)

16

SMSC USB2512A

 

DATASHEET