20H04 Datasheet, PDF (23/38 Pages) SMSC Corporation – 4-PORT USB2.0 HUB CONTROLLER

4-Port USB2.0 Controller
Datasheet
Chapter 8
Implementation Notes
The following sections consist of select functional explanations to aid in implementing the Hub Controller
into a system.
8.1
Configuration Implementations
The USB20H04 is normally configured by an external EEPROM connected directly to the serial interface.
Typical circuit diagrams are shown below. For a more detailed discussion of the serial interface, including
how to configure the USB20H04 using the SMBus mode, please see Application Note 9.29, "USB20H04 4-
Port USB2.0 Hub Controller, Configuration Programming". The Application Note also discusses designing
a Hub system that supports In Circuit Programming of the EEPROM.
8.1.1
Interfacing a 2-wire Serial EEPROM
The I²C EEPROM interface is designed to attach to a single “dedicated” I²C EEPROM. It conforms to the
Standard-mode I²C Specification (100kbit/s transfer rate and 7-bit addressing) for protocol and electrical
compatibility. The circuit board designer is required to place external pull-up resistors (10K ohm
recommended) on the SDA & SCL lines (per SMBus 1.0 Specification, and EEPROM manufacturer
guidelines) to VDD in order to assure proper operation.
VDD3.3
1k
USB20H04
SMB_SEL_N
CS/EE_SEL
SCK/SCL
SD/SDA
VDD3.3
10k 10k ^24C02A
SCL
SDA
Figure 8.1 - 2-Wire EEPROM Interface
SMSC USB20H04
Page 23
DATASHEET
Revision 1.63 (10-14-04)