2-Port USB 2.0 Hub Controller

Datasheet

Table 4.1 2-Port Hub Pin Descriptions (continued)

NAME

 

SYMBOL

 

 

TYPE

 

 

FUNCTION

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SERIAL PORT INTERFACE

 

 

 

 

 

 

 

 

 

 

 

Serial Data/SMB

 

SDA/SMBDATA

IOSD12

 

(Serial Data)/(SMB Data) signal.

Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Serial Clock/SMB

 

SCL/SMBCLK/

IOSD12

 

(Serial Clock)/(SMB Clock) signal. This multifunction pin is

Clock

 

CFG_SEL0

 

 

 

 

read on the rising edge of RESET_N (see the applicable

&

 

 

 

 

 

 

 

 

 

RESET_N timing table in Section 5.6.1) and will determine

Config Select 0

 

 

 

 

 

 

 

the hub configuration method as described in Table 4.2.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Configuration

 

CFG_SEL1

 

 

I

 

This pin is read on the rising edge of RESET_N (see the

Programming

 

 

 

 

 

 

 

applicable RESET_N timing table in Section 5.6.1) and will

Select

 

 

 

 

 

 

 

determine the hub configuration method as described in

 

 

 

 

 

 

 

 

 

 

Table 4.2.

 

 

 

 

Table 4.2 SMBus or EEPROM Interface Behavior

 

 

 

 

 

 

 

 

 

 

 

 

CFG_SEL1

 

CFG_SEL0

SMBus or EEPROM interface behavior.

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

0

Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

1

Configured as an SMBus slave for external download of user-

 

 

 

 

 

 

 

 

 

defined descriptors. SMBus slave address is 0101100

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

0

Internal Default Configuration via strapping options.

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

1

2-wire (I2C) EEPROMS are supported,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 4.3 Miscellaneous Pins

 

 

 

 

 

 

 

 

 

 

NAME

 

 

SYMBOL

 

 

TYPE

 

 

FUNCTION

 

 

 

 

 

 

 

 

 

 

Crystal

 

 

XTAL1/

 

 

ICLKx

 

 

24MHz crystal or external clock input.

Input/External

 

 

CLKIN

 

 

 

 

 

This pin connects to either one terminal of the crystal or

Clock Input

 

 

 

 

 

 

 

 

 

to an external 24MHz clock when a crystal is not used.

 

 

 

 

 

 

 

 

 

 

Crystal Output

 

 

XTAL2

 

 

OCLKx

 

 

24MHz Crystal

 

 

 

 

 

 

 

 

 

 

 

This is the other terminal of the crystal, or left

 

 

 

 

 

 

 

 

 

 

 

unconnected when an external clock source is used to

 

 

 

 

 

 

 

 

 

 

 

drive XTAL1/CLKIN. It must not be used to drive any

 

 

 

 

 

 

 

 

 

 

 

external circuitry other than the crystal circuit.

 

 

 

 

 

 

 

 

 

 

Clock Input

 

 

CLKIN_EN

 

 

I

 

 

Clock In Enable:

Enable

 

 

 

 

 

 

 

 

 

Low = XTAL1 and XTAL2 pins configured for use with

 

 

 

 

 

 

 

 

 

 

 

external crystal

 

 

 

 

 

 

 

 

 

 

 

High = XTAL1 pin configured as CLKIN, and must be

 

 

 

 

 

 

 

 

 

 

 

driven by an external CMOS clock.

 

 

 

 

 

 

 

 

 

 

RESET Input

 

 

RESET_N

 

 

IS

 

 

This active low signal is used by the system to reset the

 

 

 

 

 

 

 

 

 

 

 

chip. The minimum active low pulse is 1us.

 

 

 

 

 

 

 

 

 

 

Self-Power /

 

 

SELF_PWR

 

 

I

 

 

Detects availability of local self-power source.

Bus-Power

 

 

 

 

 

 

 

 

 

Low = Self/local power source is NOT available (i.e., Hub

Detect

 

 

 

 

 

 

 

 

 

gets all power from Upstream USB VBus).

 

 

 

 

 

 

 

 

 

 

 

High = Self/local power source is available.

 

 

 

 

 

 

 

 

 

 

TEST Pin

 

 

TEST

 

 

IPD

 

 

Used for testing the chip. User must treat as a no-

 

 

 

 

 

 

 

 

 

 

 

connect or connect to ground.

 

 

 

 

 

 

 

 

 

 

 

 

SMSC USB2502

13

Revision 2.3 (08-27-07)

 

DATASHEET