USB MultiSwitchTM Hub

Datasheet

Chapter 4 Switching Hub Pin Descriptions

Table 4.1 Switching Hub Pin Descriptions

NAME

SYMBOL

 

TYPE

FUNCTION

 

 

 

 

 

 

 

UPSTREAM USB 2.0 INTERFACE

 

 

 

 

 

USB Bus Data

USBUP_DP[2:1]

 

IO-U

These pins connect to the upstream USB bus data signals.

 

USBUP_DM[2:1]

 

 

 

 

 

 

 

 

Detect Upstream

VBUS_DET[2:1]

 

I/O

Detects state of Upstream VBUS power. The SMSC Hub

VBUS Power

 

 

 

monitors VBUS_DET to determine when to assert the

 

 

 

 

internal D+ pull-up resistor (signalling a connect event).

 

 

 

 

When designing a detachable hub, this pin must be

 

 

 

 

connected to the VBUS power pin of the USB port that is

 

 

 

 

upstream of the hub. (Use of a weak pull-down resistor is

 

 

 

 

recommended.)

 

 

 

 

For self-powered applications with a permanently attached

 

 

 

 

host, this pin must be pulled-up to either 3.3V or 5.0V

 

 

 

 

(typically VDD33).

 

 

 

 

 

 

 

4-PORT USB 2.0 HUB INTERFACE

 

 

 

 

 

High-Speed USB

USBDN_DP[4:1]

 

IO-U

These pins connect to the downstream USB peripheral

Data

USBDN_DM[4:1]

 

 

devices attached to the Hub’s ports.

 

 

 

 

 

USB Power

PRTPWR[4:1]

 

O

Enables power to USB peripheral devices (downstream).

Enable

 

 

 

The active signal level of the PRTPWR[4] pin is determined

 

 

 

 

 

 

 

 

by the Power Polarity Strapping function of the

 

 

 

 

PRTPWR_POL pin.

 

 

 

 

 

Port 4:3 Green

LED_A[4:3]_N/

 

I/O12

Green indicator LED for ports 4 and 3. Will be active low

LED

PRT_DIS[1:0]

 

 

when LED support is enabled via EEPROM or SMBus. See

&

 

 

 

PRT_DIS1 function description if the hub is configured by

Port Disable

 

 

 

the internal default configuration.

strapping option 0

 

 

 

 

 

 

 

 

 

Port Disable

PRT_DIS1

 

I/O12

If the hub is configured by the internal default configuration,

strapping option 1

 

 

 

PRT_DIS[1:0] will be sampled at RESET_N negation to

 

 

 

 

determine if ports [4:2] will be permanently disabled. Also,

 

 

 

 

the active state of LED_A3_N will be determined as follows:

 

 

 

 

PRT_DIS[1:0] = '00', All ports are enabled,

 

 

 

 

LED_A4_N is active high,

 

 

 

 

LED_A3_N is active high.

 

 

 

 

PRT_DIS[1:0] = '01', Port 4 is disabled,

 

 

 

 

LED_A4_N is active high,

 

 

 

 

LED_A3_N is active low.

 

 

 

 

PRT_DIS[1:0] = '10', Ports 4 & 3 are disabled,

 

 

 

 

LED_A4_N is active low,

 

 

 

 

LED_A3_N is active high.

 

 

 

 

PRT_DIS[1:0] = '11', Ports 4, 3 & 2 are disabled,

 

 

 

 

LED_A4_N is active low,

 

 

 

 

LED_A3_N is active low.

 

 

 

 

 

Revision 1.91 (08-22-07)

12

SMSC USB2524

 

DATASHEET