Datasheet

USB 2.0 Hi-Speed Hub Controller
Datasheet
Revision 2.3 (06-11-13) 32 SMSC USB251xB/xBi
DATASHEET
5.1.13 Register 0Ch: Max Power For Self-Powered Operation
5.1.14 Register 0Dh: Max Power For Bus-Powered Operation
5.1.15 Register 0Eh: Hub Controller Max Current For Self-Powered Operation
BIT
NUMBER BIT NAME DESCRIPTION
7:0 MAX_PWR_SP Max Power Self-Powered: the value in 2 mA increments that the hub
consumes from an upstream port (VBUS) when operating as a self-powered
hub. This value includes the hub silicon along with the combined power
consumption (from VBUS) of all associated circuitry on the board. This value
also includes the power consumption of a permanently attached peripheral
if the hub is configured as a compound device. The embedded peripheral
reports 0 mA in its descriptors.
Note: The USB 2.0 Specification does not permit this value to exceed
100 mA
BIT
NUMBER BIT NAME DESCRIPTION
7:0 MAX_PWR_BP Max Power Bus-Powered: the value in 2 mA increments that the hub
consumes from an upstream port (VBUS) when operating as a bus-powered
hub. This value includes the hub silicon along with the combined power
consumption (from VBUS) of all associated circuitry on the board. This value
also includes the power consumption of a permanently attached peripheral
if the hub is configured as a compound device. The embedded peripheral
reports 0 mA in its descriptors.
BIT
NUMBER BIT NAME DESCRIPTION
7:0 HC_MAX_C_SP Hub Controller Max Current Self-Powered: the value in 2 mA increments that
the hub consumes from an upstream port (VBUS) when operating as a self-
powered hub. This value includes the hub silicon along with the combined
power consumption (from VBUS) of all associated circuitry on the board.
This value does NOT include the power consumption of a permanently
attached peripheral if the hub is configured as a compound device.
Note: The USB 2.0 Specification does not permit this value to exceed
100 mA
A value of 50 (decimal) indicates 100 mA, which is the default value.