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High Speed Inter-Chip USB 2.0 Hub and Flash Media Controller
Datasheet
Revision 1.0 (06-01-09) 42 SMSC USB4640/USB4640i
DATASHEET
8.4.4.8 E5h: Configuration Data Byte 2 (CFG_DAT_BYT2)
8.4.4.9 E6h: Configuration Data Byte 3 (CFG_DAT_BYT3)
4:3 Reserved Reserved
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 per port or ganged basis is dependent upon the
hardware implementation.
‘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!)
0 PORT_PWR Port Power Switching: Enables power switching on all ports simultaneously
(ganged), or port power is individually switched on and off on a port-by-port
basis (individual). The ability to support power enabling on a port or ganged
basis is dependent upon the hardware implementation.
‘0’ = Ganged switching (all ports together)
‘1’ = Individual port-by-port switching
BIT NAME DESCRIPTION
7:6 Reserved Reserved
5:4 OC_TIMER OverCurrent Timer: Over-current timer delay.
‘00’ = 50 ns
‘01’ = 100 ns
‘10’ = 200 ns
‘11’ = 400 ns
3 COMPOUND Compound Device: Allows OEM to indicate that the hub is part of a
compound device (per the USB 2.0 Specification). The applicable port(s)
must also be defined as having a “non-removable device”.
Note: When configured via strapping options, declaring a port as non-
removable automatically causes the hub controller to report that it
is part of a compound device.
‘0’ = No
‘1’ = Yes, the hub is part of a compound device
2:0 Reserved Reserved
BIT NAME DESCRIPTION
7:4 Reserved Reserved
BIT NAME DESCRIPTION