USB2504A datasheet(9/42 Pages) MICROCHIP

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 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 Table 4-2.

Configuration

Programming

Select

CFG_SEL1

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

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

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