SMSC USB2507 Manual De Usuario

Integrated USB 2.0 Compatible 7-Port Hub

SMSC USB2507

11

Revision 2.3 (08-27-07)

Port 4 Amber 

LED

&

LED Enable 

strapping option

AM4/

LED_EN

I/O12

Amber indicator LED for port 4. Will be active low when LED 
support is enabled via EEPROM or SMBus.

If the hub is configured by the internal default configuration, 
this pin will be sampled at RESET_N negation to determine 
if LED support is enabled or disabled. Also, the active state 
of the LED will be determined as follows:

‘0’ = LED support is disabled, LED is inactive
‘1’ = LED Support is enabled, LED is active low.

Port 3 Amber 

LED

AM3

I/O12

Amber indicator LED for port 3. Signal will be active low.

Port 2 Amber 

LED

&

MTT Disable

AM2/

MTT_EN

I/O12

Amber indicator LED for port 2. Will be active low when LED 
support is enabled via EEPROM or SMBus.

If the hub is configured by the internal default configuration, 
this pin will be sampled at RESET_N negation to determine 
if MTT support is disabled (STT only). Also, the active state 
of the LED will be determined as follows:

‘0’ = MTT support is disabled, LED is active high
‘1’ = MTT support is enabled, LED is active low.

Port 1 Amber 

LED

&

Gang Power 

Switching and 

Current Sensing 

strapping option.

AM1/

GANG_EN

I/O12

Amber indicator LED for port 1, Will be active low when LED 
support is enabled via EEPROM or SMBus.

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. Also, the active state of 
the LED will be determined as follows:

‘0’ = Port-by-port sensing & switching, LED is active high
‘1’ = Ganged sensing & switching, LED is active low.

Port Power 

Polarity strapping.

PRTPWR_POL

I/O12

Port Power Polarity strapping determination for the active 
signal polarity of the 7:1PRTPWR pins. 

While RESET_N is asserted, the logic state of this pin will 
(though the use of internal combinatorial logic) determine 
the active state of the 7:1PRTPWR pins in order to ensure 
that downstream port power is not inadvertently enabled to 
inactive ports during a hardware reset.

On the rising edge of RESET_N (see the applicable 
RESET_N timing table in 

), the logic value will 

be latched internally, and will retain the active signal polarity 
for the PRTPWR7:1 pin.

‘1’ = PRTPWR7:1 pins have an active ‘high’ polarity
‘0’ = PRTPWR7:1 pins have an active ‘low’ polarity

Over Current 

Sense

OCS7:1_N

IPU

Input from external current monitor indicating an over-
current condition. {Note: Contains internal pull-up to 3.3V 
supply}

USB Transceiver 

Bias

RBIAS

I-R

A 12.0k

Ω (+/− 1%) resistor is attached from ground to this 

pin to set the transceiver’s internal bias settings.