20H04 Datasheet, PDF (25/38 Pages) SMSC Corporation – 4-PORT USB2.0 HUB CONTROLLER

4-Port USB2.0 Controller
Datasheet
Detailed definition of the bits used to program the OEM values are given in Table 8.2 through Table 8.5.
Table 8.2 - Address 6; Config_Byte_3
BIT
FIELD NAME
DESCRIPTION
7
Self-/Bus-Power Selects either self-powered or bus-powered operation:
0: Self-powered operation.
1: Bus-powered operation.
6
Port Indicators Selects implementation of port indicators:
0: No port indicators.
1: Port indicators implemented.
5
High-Speed
Selects whether high-speed operation is disabled:
Disable
0: High-/Full-Speed operation.
1: Full-Speed only (High-Speed disabled).
4
Multiple TT Support Selects whether multiple transaction translators are available:
0: Single TT for all ports.
1: Each port has one TT available (multiple TTs supported).
3
EOP Disable
Selects whether EOP generation of EOF1 is disabled when in
Full-Speed mode:
0: EOP generation at EOF1.
1: EOP generation at EOF1 disabled.
2
Current Sensing Selects whether current sensing is ganged on all ports, or on an
individual port-by-port basis:
0: Individual port-by-port.
1: Ganged sensing.
1
Power Switching Selects whether downstream port power switching is ganged on all
ports, or on an individual port-by-port basis:
0: Individual port-by-port.
1: Ganged switching.
0
Compound Device Selects whether the hub is part of a compound device:
0: Not a compound device.
1: Yes, USB20H04 is part of a compound device.
Table 8.3 - Address 7; Config_Byte_2
The ports may be individually configured to be inactive. However, the order in which ports are set to
inactive is very specific. Port 4 must be the first port configured to be inactive, followed by port 3.
BIT
FIELD NAME
DESCRIPTION
7:4
Non-Removable Selects which ports include non-removable devices. A one
Device
indicates that the port is non-removable:
Bit 7: Port 4 is non-removable.
Bit 6: Port 3 is non-removable.
Bit 5: Port 2 is non-removable.
Bit 4: Port 1 is non-removable.
All zeroes sets all ports removable.
SMSC USB20H04
Page 25
DATASHEET
Revision 1.63 (10-14-04)