2007 - 2016 Microchip Technology Inc. DS000002250A-page 9
USB2504/USB2504A
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 [4:1]PRTPWR 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 [4:1]PRTPWR 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 Section 5.6.1), the logic value will
be latched internally, and will retain the active signal polarity
for the PRTPWR[4:1] pins.
‘1’ = PRTPWR[4:1]_P/N pins have an active ‘high’ polarity
‘0’ = PRTPWR[4:1]_P/N pins have an active ‘low’ polarity
Over Current
Sense
OCS[4:1]_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 (resistor is attached from ground to this pin
to set the transceiver’s internal bias settings.
SERIAL PORT INTERFACE
Serial Data/SMB
Data
SDA/SMBDATA IOSD12 (Serial Data)/(SMB Data) signal.
Serial Clock/SMB
Clock
SCL/SMBCLK IOSD12 (Serial Clock)/(SMB Clock) signal.
Configuration
Programming
Select
CFG_SEL0 IOSD12 This multifunction pin is read on the rising edge of RESET_N
negation and will determine the hub configuration method as
described in Tab le 4-2.
Configuration
Programming
Select
CFG_SEL1 I This pin is read on the rising edge of RESET_N (see the
applicable RESET_N timing table in Section 5.6.1) and will
determine the hub configuration method as described in
Table 4-2.
Configuration
Programming
Select
CFG_SEL2 I This pin is read on the rising edge of RESET_N negation and
will determine the hub configuration method as described in
Table 4-2.
TABLE 4-1: 4-PORT HUB PIN DESCRIPTIONS (CONTINUED)
Name Symbol Type Function
