USB3503 datasheet(45/82 Pages) SMSC

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USB 2.0 HSIC High-Speed Hub Controller Optimized for Portable Applications

Datasheet

SMSC USB3503A

Revision 1.1 (02-07-13)

DATASHEET

Chapter 6 Serial Slave Interface

6.1

Overview

The serial slave interface on USB3503 is implemented as I2C. It is a standard I2C slave interface that

operates at the standard (100Kbps), fast (400Kbps), and the fast mode plus (1Mbps) modes.

The USB3503 I2C slave interface address is 0x08h.

REFCLK must be running for I2C to operate. The register map is outlined in section Section 5.3.

The I2C Slave Base Address is 0x08. The interrupt pin INT_N is used to communicate status changes

on selected events that are mapped into the Serial Port Interrupt Status Register. INT_N is asserted

low whenever an unmasked bit is set in the Serial Port Interrupt Status Register. SOC must update

the Serial Port Interrupt Status Register to negate the interrupt high.

The SOC can mask events to not cause the interrupt pin to transition by updating the Serial Port

Interrupt Mask Register. The status events will still be captured in the status register even if the

interrupt pin is not asserted. The serial port has limited speed and latency capability so events mapped

into the serial ports and its interrupt are not expected to be latency critical.

6.2

Interconnecting the USB3503 to an I2C Master

Note 6.1

The largest pullup values which meet the customer application should be selected in order

to minimize power consumption. Pullup values must also have low enough resistance to

support the desired i2C operating speed with the expected total capacitance in the

Figure 6.1 I2C Connections

I2C

MASTER

CONTROLLER

USB3503

SCL

SDA

SOC

SCL

SDA

VDD

INT

USB3503 Datenblatt(PDF) 45 Page - SMSC Corporation