USB2502-HT datasheet(9/40 Pages) MICROCHIP

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 2007 - 2016 Microchip Technology Inc.

DS000002248A-page 9

USB2502

2-PORT USB 2.0 HUB INTERFACE

High-Speed USB

Data

USBDN[2:1]

USBDP[2:1]

IO-U

These pins connect to the downstream USB peripheral

devices attached to the Hub’s ports.

USB Power Enable

PRTPWR

Enables power to USB peripheral devices (downstream).

The active signal level of the PRTPWR pin is determined by

the Power Polarity Strapping function of the PRTPWR_POL

pin.

Port [2:1] Green

LED

Port Non-

Removable

strapping option.

GR[2:1]/

NON_REM[1:0]

I/O8

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 the rising edge of RESET_N

(see the applicable RESET_N timing table in Section 5.6.1)

to determine if ports [2:1] 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 are non-removable,

GR2 is active low,

GR1 is active low.

Port Power Polarity

strapping.

PRTPWR_POL

I/O8

Port Power Polarity strapping determination for the active

signal polarity of the PRTPWR pin.

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 PRTPWR pin 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 pin.

‘1’ = PRTPWR pin has an active ‘high’ polarity

‘0’ = PRTPWR pin has an active ‘low’ polarity

Over Current

Sense

OCS_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.

TABLE 4-1:

2-PORT HUB PIN DESCRIPTIONS (CONTINUED)

Name

Symbol

Type

Function

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