- Standard Microsystems 2-Port Hub Controller Specification Sheet

Industrial Temperature Rated USB 2.0 High-Speed 2-Port Hub Controller
Datasheet
SMSC USB2512i 17 Revision 1.92 (11-28-07)
DATASHEET
4.2.1.8 Register 07h: Configuration Data Byte 2
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 hardware implementation dependent.
0 = Ganged switching (all ports together)
1 = Individual port-by-port switching
BIT
NUMBER BIT NAME DESCRIPTION
7 DYNAMIC Dynamic Power Enable: Controls the ability of the Hub to automatically
change from Self-Powered operation to Bus-Powered operation if the local
power source is removed or is unavailable (and from Bus-Powered to Self-
Powered if the local power source is restored). {Note: If the local power
source is available, the Hub will always switch to Self-Powered operation.}
When Dynamic Power switching is enabled, the Hub detects the availability
of a local power source by monitoring the external LOCAL_PWR pin. If the
Hub detects a change in power source availability, the Hub immediately
disconnects and removes power from all downstream devices and
disconnects the upstream port. The Hub will then re-attach to the upstream
port as either a Bus-Powered Hub (if local-power is unavailable) or a Self-
Powered Hub (if local power is available).
0 = No Dynamic auto-switching
1 = Dynamic Auto-switching capable
6 Reserved Reserved
5:4 OC_TIMER OverCurrent Timer: Over Current Timer delay.
00 = 0.1ms
01 = 4ms
10 = 8ms
11 = 16ms
3 COMPOUND
Compound Device: Allows the OEM to indicate that the Hub is part
of a compound (see the USB Specification for definition) device. 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, Hub is part of a compound device
2:0 Reserved Reserved
BIT
NUMBER BIT NAME DESCRIPTION