USB3503 datasheet(20/82 Pages) SMSC

20 / 82 page

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

Datasheet

SMSC USB3503A

Revision 1.1 (02-07-13)

DATASHEET

Chapter 4 Modes of Operation

The USB3503 provides two modes of operation - Standby Mode and Hub Mode - which balance power

consumption with functionality. The operating mode of the USB3503 is selected by setting values on

primary inputs according to the table below.

4.1

Operational Mode Flowchart

The flowchart in Figure 4.1 shows the modes of operation. It also shows how the USB3503 traverses

through the Hub mode stages (shown in bold.) The flow of control is dictated by control register bits

shown in Italics as well as other events such as availability of reference clock. Refer to Section 5.3,

"Serial Interface Register Definitions," on page 28 for the detailed definition of the control register bits.

In this specification register bits are referenced using the syntax <Register>.<RegisterBit>. A summary

of all registers can be found in Table 5.2, “Serial Interface Registers,” on page 26.

The remaining sections in this chapter provide more detail on each stage and mode of operation.

Table 4.1 Controlling Modes of Operation

RESET_N

INPUT

RESULTING

MODE

SUMMARY

Standby

Lowest Power Mode – no function other than monitoring RESET_N

input to move to higher states. All regulators are powered off.

Hub

Full Feature Mode - Operates as a configurable USB hub. Power

consumption based on how many ports are active, at what speeds

they are running and amount of data transferred.

USB3503 Datasheet(PDF) 20 Page - SMSC Corporation