2-Port USB 2.0 Hub Controller

Datasheet

5.2EEPROM Interface

The SMSC Hub can be configured via a 2-wire (I2C) EEPROM. (Please see Table 4.1, "7-Port Hub Pin Descriptions" for specific details on how to enable the I2C EEPROM option).

The Internal state-machine will, (when configured for EEPROM support) read the external EEPROM for configuration data. The hub will then “attach” to the upstream USB host.

Please see Table 5.1 User-Defined Descriptor Data for a list of data fields available.

5.2.1I2C EEPROM

The I2C EEPROM interface implements a subset of the I2C Master Specification (Please refer to the Philips Semiconductor Standard I2C-Bus Specification for details on I2C bus protocols). The Hub’s I2C EEPROM interface is designed to attach to a single “dedicated” I2C EEPROM, and it conforms to the Standard-mode I2C Specification (100kbit/s transfer rate and 7-bit addressing) for protocol and electrical compatibility.

Note: Extensions to the I2C Specification are not supported.

The Hub acts as the master and generates the serial clock SCL, controls the bus access (determines which device acts as the transmitter and which device acts as the receiver), and generates the START and STOP conditions.

5.2.1.1Implementation Characteristics

Please refer to the MicroChip 24AA00 DataSheet for Protocol and Programming specifics.

5.2.1.2Pull-Up Resistor

The Circuit board designer is required to place external pull-up resistors (10KΩ recommended) on the SDA/SMBDATA & SCL/SMBCLK/CFG_SELO lines (per SMBus 1.0 Specification, and EEPROM manufacturer guidelines) to Vcc in order to assure proper operation.

5.2.1.3I2C EEPROM Slave Address

Slave address is 1010000.

Note: 10-bit addressing is NOT supported.

5.2.2In-Circuit EEPROM Programming

The EEPROM can be programmed via ATE by pulling RESET_N low (which tri-states the Hub’s EEPROM interface and allows an external source to program the EEPROM).

5.2.3EEPROM DATA

Table 5.1 User-Defined Descriptor Data

 

 

 

DEFAULT

DEFAULT

 

 

BYTE

 

CFG

CFG

 

 

MSB:

SIZE

SELF

BUS

 

FIELD

LSB

(BYTES)

(HEX)

(HEX)

DESCRIPTION

 

 

 

 

 

 

VID

1:0

2

0424

0424

Vendor ID (assigned by USB-IF).

 

 

 

 

 

 

PID

3:2

2

2502

2502

Product ID (assigned by Manufacturer).

 

 

 

 

 

 

DID

5:4

2

0000

0000

Device ID (assigned by Manufacturer).

 

 

 

 

 

 

SMSC USB2502

19

Revision 2.3 (08-27-07)

 

DATASHEET