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Ultra Fast USB 2.0 Multi-Format Flash Media Controller/USB Hub Combo
SMSC USB2640/USB2641 41 Revision 2.0 (10-03-08)
DATASHEET
7.3.3.22 E9h: Port Disable For Bus-Powered Operation
7.3.3.23 EAh: Max Power For Self-Powered Operation
7.3.3.24 EBh: Max Power For Bus-Powered Operation
BIT
NUMBER BYTE NAME DESCRIPTION
7:0 PORT_DIS_BP Port Disable Bus-Powered: Disables 1 or more ports. ‘0’ = port is available,
‘1’ = port is disabled.
During Self-Powered operation
, this register selects the ports which will be
permanently disabled. The ports are unavailable to be enabled or
enumerated by a Host Controller. The ports can be disabled in any order,
the internal logic will automatically report the correct number of enabled ports
to the USB host and will reorder the active ports in order to ensure proper
function.
When using the internal default option, the PRT_DIS[1:0] pins will disable the
appropriate ports.
Bit 7= Reserved
Bit 6= Reserved
Bit 5= Reserved
Bit 4= Reserved
Bit 3= 1; Port 3 is disabled
Bit 2= 1; Port 2 is disabled
Bit 1= 1; Port 1 is disabled
Bit 0 is Reserved, always = ‘0’
BIT
NUMBER BYTE NAME DESCRIPTION
7:0 MAX_PWR_SP Max Power Self_Powered: 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, and 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 BYTE NAME DESCRIPTION
7:0 MAX_PWR_BP Max Power Bus_Powered: 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, and the embedded peripheral reports 0
mA in its descriptors.