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High Speed Inter-Chip USB 2.0 Hub and Flash Media Controller
Datasheet
SMSC USB4640/USB4640i 45 Revision 1.0 (06-01-09)
DATASHEET
8.4.4.14 EBh: Max Power For Bus-Powered Operation
8.4.4.15 ECh: Hub Controller Max Current For Self-Powered Operation
8.4.4.16 EDh: Hub Controller Max Current For Bus-Powered Operation
8.4.4.17 EEh: Power-On Time
BIT BYTE NAME DESCRIPTION
7:0 MAX_PWR_BP Value in 2 mA increments that the hub consumes when operating as a bus-
powered hub. This value includes the hub silicon along with the combined
power consumption 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, and the embedded peripheral
reports 0 mA in its descriptors.
BIT BYTE NAME DESCRIPTION
7:0 HC_MAX_C_SP Value in 2 mA increments that the hub consumes when operating as a self-
powered hub. This value includes the hub silicon along with the combined
power consumption 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.
BIT BYTE NAME DESCRIPTION
7:0 HC_MAX_C_BP Value in 2 mA increments that the hub consumes when operating as a bus-
powered hub. This value will include the hub silicon along with the combined
power consumption 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 100 mA, which is the default value.
BIT BYTE NAME DESCRIPTION
7:0 PWR_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 adequate on that
port. If the host requests the power-on time, the system software uses this
value to determine how long to wait before accessing a powered-on port.