SMSC USB2512Ai ユーザーズマニュアル

Industrial Temperature Rated USB 2.0 Hi-Speed 2-Port Hub Controller

Revision 1.97 (08-11-08)

24

SMSC USB2512Ai

The I

2

C EEPROM interface implements a subset of the I

2

C Master Specification (Please refer to the

Philips Semiconductor Standard I

2

C-Bus Specification for details on I

2

C bus protocols). The Hub’s I

2

C

EEPROM interface is designed to attach to a single “dedicated” I

2

C EEPROM, and it conforms to the

Standard-mode I

2

C Specification (100kbit/s transfer rate and 7-bit addressing) for protocol and

electrical compatibility.

Note: Extensions to the I

2

C 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.

The Hub will only access an EEPROM using the Sequential Read Protocol. 

The Circuit board designer is required to place external pull-up resistors (10K

Ω 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.

Slave address is 1010000. 

Note: 10-bit addressing is NOT supported.

7:3

Reserved

Reserved

2

INTF_PW_DN

SMBus Interface Power Down

‘0’ = Interface is active
‘1’ = Interface power down after ACk has completed

1

RESET

Reset the SMBus Interface and internal memory back to RESET_N 
assertion default settings. 

‘0’ = Normal Run/Idle State
‘1’ = Force a reset of registers to their default state

0

USB_ATTACH

USB Attach (and write protect)

‘0’ = SMBus slave interface is active
‘1’ = Hub will signal a USB attach event to an upstream device, and the 
internal memory (address range 00h-FEh) is “write-protected” to prevent 
unintentional data corruption.