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Integrated USB 2.0 Compatible 3-Port Hub
Datasheet
Revision 2.3 (08-27-07) 10 SMSC USB2503/USB2503A
DATASHEET
3-PORT USB 2.0 HUB INTERFACE
High-Speed USB
Data
USBDN[3:1]
USBDP[3:1]
IO-U These pins connect to the downstream USB peripheral
devices attached to the Hub’s ports.
USB Power
Enable
PRTPWR[3:1] O12 Enables power to USB peripheral devices (downstream).
The active signal level of the PRTPWR[3:1] pins are
determined by the Power Polarity Strapping function of the
PRTPWR_POL pin.
Port 3 Green LED
&
Port Disable
strapping option.
GR3/
PRT_DIS0
I/O12 Green indicator LED for port 3. Will be active low when LED
support is enabled via EEPROM or SMBus.
If the hub is configured by the internal default configuration,
these pins will be sampled at RESET_N negation to
determine if port 3 will be permanently disabled. Also, the
active state of the LED will be determined as follows:
PRT_DIS0 = ‘0’, All ports are enabled,
GR3 is active high.
PRT_DIS0 = ‘1’, Port 3 is disabled,
GR3 is active low.
Port [2:1] Green
LED
&
Port Non-
Removable
strapping option.
GR[2:1]/
NON_REM[1:0]
I/O12 Green indicator LED for ports 2 and 1. Will be active low
when LED support is enabled via EEPROM or SMBus.
If the hub is configured by the internal default configuration,
these pins will be sampled at RESET_N negation to
determine if ports [3:1] contain permanently attached (non-
removable) devices. Also, the active state of the LED’s will
be determined as follows:
NON_REM[1:0] = ‘00’, All ports are removable,
GR2 is active high,
GR1 is active high.
NON_REM1:0] = ‘01’, Port 1 is non-removable,
GR2 is active high,
GR1 is active low.
NON_REM[1:0] = ‘10’, Ports 1 & 2 are non-removable,
GR2 is active low,
GR1 is active high.
NON_REM[1:0] = ‘11’, Ports 1, 2, & 3 are non-removable,
GR2 is active low,
GR1 is active low.
Gang Power
Switching and
Current Sensing
strapping option.
GANG_EN I/O12 If the hub is configured by the internal default configuration,
this pin will be sampled at RESET_N negation to determine
if downstream port power switching and current sensing are
ganged, or individual port-by-port.
‘0’ = Port-by-port sensing & switching.
‘1’ = Ganged sensing & switching.
Table 4.1 3-Port Hub Pin Descriptions (continued)
NAME SYMBOL TYPE FUNCTION