USB 2.0 Hi-Speed 2-Port Hub Controller

Datasheet

4.2.1.16Register 0Fh: Hub Controller Max Current For Bus Powered Operation

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7:0

HC_MAX_C_BP

Hub Controller Max Current Bus-Powered: Value in 2mA increments that the

 

 

Hub consumes from an upstream port (VBUS) when operating as a bus-

 

 

powered hub. This value will include the hub silicon along with the combined

 

 

power consumption (from VBUS) of all associated circuitry on the board.

 

 

This value will NOT include the power consumption of a permanently

 

 

attached peripheral if the hub is configured as a compound device.

 

 

A value of 50 (decimal) would indicate 100mA, which is the default value.

 

 

 

4.2.1.17Register 10h: Power-On Time

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7:0

POWER_ON_TIME

Power On Time: The length of time that it takes (in 2 ms intervals) from the

 

 

time the host initiated power-on sequence begins on a port until power is

 

 

good on that port.

 

 

 

4.2.1.18Register F6h: Boost_Up

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7:2

Reserved

Reserved

 

 

 

1:0

BOOST_IOUT

USB electrical signaling drive strength Boost Bit for the Upstream Port.

 

 

‘00’ = Normal electrical drive strength = No boost

 

 

‘01’ = Elevated electrical drive strength = Low (approximately 4% boost)

 

 

‘10’ = Elevated electrical drive strength = Medium (approximately 8% boost)

 

 

‘11’ = Elevated electrical drive strength = High (approximately 12% boost)

 

 

Note: “Boost” could result in non-USB Compliant parameters (one

 

 

example would be Test J/K levels), the OEM should use a 00 value

 

 

unless specific implementation issues require additional signal

 

 

boosting to correct for degraded USB signalling levels.

 

 

 

4.2.1.19Register F8h: Boost_2:0

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7:4

Reserved

Reserved

 

 

 

SMSC USB2512A

21

Revision 1.96 (07-11-08)

 

DATASHEET