Datasheet

USB 2.0 Hi-Speed 7-Port Hub Controller
Datasheet
SMSC USB2517 23 Revision 2.8 (09-17-12)
DATASHEET
7.2.1.8 Register 07h: Configuration Data Byte 2
4 MTT_ENABLE Multi-TT enable: Enables one transaction translator per port operation.
Selects between a mode where only one transaction translator is available
for all ports (Single-TT), or each port gets a dedicated transaction translator
(Multi-TT) {Note: The host may force single-TT mode only}.
0 = single TT for all ports
1 = one TT per port (multiple TT’s supported)
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 = EOP generation is normal
1 = EOP generation is disabled
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 hardware implementation dependent.
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 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
BIT
NUMBER BIT NAME DESCRIPTION