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Ultra Fast USB 2.0 Multi-Format Flash Media Controller/USB Hub Combo
Revision 2.0 (10-03-08) 38 SMSC USB2640/USB2641
DATASHEET
7.3.3.18 E5h: Config Data Byte 2 (CFG_DAT_BYT2)
5 HS_DISABLE Hi-Speed Disable: Disables the capability to attach as either a Hi-/Full-Speed
device, and forces attachment as Full-Speed only (i.e. no Hi-Speed support).
0 = Hi-/Full-Speed
1 = Full-Speed-Only (Hi-Speed disabled!)
4 Reserved Always reads ‘0’.
3 EOP_DISABLE EOP Disable: Disables EOP generation of EOF1 when in Full-Speed mode.
During FS operation only, this permits the hub to send EOP if no
downstream traffic is detected at EOF1. See Section 11.3.1 of the USB 2.0
Specification for additional details. Note: generation of an EOP at the EOF1
point may prevent a Host Controller (operating in FS mode) from placing the
USB bus in suspend.
0 = An EOP is generated at the EOF1 point if no traffic is detected.
1 = EOP generation at EOF1 is disabled (Note: This is normal USB
operation).
Note: This is a rarely used feature in the PC environment, existing drivers
may not have been thoroughly debugged with this feature enabled.
It is included because it is a permitted feature in Chapter 11 of the
USB specification.
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 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
NUMBER BIT NAME DESCRIPTION
7:6 Reserved Always reads ‘0’.
5:4 OC_TIMER OverCurrent Timer: Over-current Timer delay.
00 = 50 ns
01 = 100 ns
10 = 200 ns
11 = 400 ns
BIT
NUMBER BIT NAME DESCRIPTION