SMSC USB2502 Manuel D’Utilisation

2-Port USB 2.0 Hub Controller

SMSC USB2502

11

Revision 2.3 (08-27-07)

USB Bus Data

USBDN0
USBDP0

IO-U

These pins connect to the upstream USB bus data signals. 

Detect Upstream 

VBUS Power

VBUS_DET

I/O8

Detects state of Upstream VBUS power. The SMSC Hub 
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).

8SVWUHDP

V

BUS

3.3V

Upstream

USB Data

24 MHz

Crystal

To EEPROM or

SMBus Master

SCK

SD

Downstream

USB Data

OC

Sense

Switch/LED

Driver/optís

Downstream

USB Data

1.8V