USB2502-HT datasheet(13/44 Pages) SMSC

13 / 44 page

2-Port USB 2.0 Hub Controller

Datasheet

SMSC USB2502

Revision 2.1 (12-06-06)

DATASHEET

SERIAL PORT INTERFACE

Serial Data/SMB

Data

SDA/SMBDATA

IOSD12

(Serial Data)/(SMB Data) signal.

Serial Clock/SMB

Clock

Config Select 0

SCL/SMBCLK/

CFG_SEL0

IOSD12

(Serial Clock)/(SMB Clock) signal. This multifunction 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_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.

Table 4.2 SMBus or EEPROM Interface Behavior

CFG_SEL1

CFG_SEL0

SMBus or EEPROM interface behavior.

Reserved

Configured as an SMBus slave for external download of user-

defined descriptors. SMBus slave address is 0101100

Internal Default Configuration via strapping options.

2-wire (I2C) EEPROMS are supported,

Table 4.3 Miscellaneous Pins

NAME

SYMBOL

TYPE

FUNCTION

Crystal

Input/External

Clock Input

XTAL1/

CLKIN

ICLKx

24MHz crystal or external clock input.

This pin connects to either one terminal of the crystal or

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

Enable

CLKIN_EN

Clock In 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

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

chip. The minimum active low pulse is 1us.

Self-Power /

Bus-Power

Detect

SELF_PWR

Detects availability of local self-power source.

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

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.

Table 4.1 2-Port Hub Pin Descriptions (continued)

NAME

SYMBOL

TYPE

FUNCTION

USB2502-HT 数据表(PDF) 13 Page - SMSC Corporation

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