USB7252CTSLASHKDX datasheet(31/63 Pages) MICROCHIP

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2021 Microchip Technology Inc.

DS00003852A-page 31

5.0

MODES OF OPERATION

The device provides two main modes of operation: Standby Mode and Hub Mode. These modes are controlled via the

RESET_N pin, as shown in Table 5-1.

The flowchart in Figure 5-1 details the modes of operation and details how the device traverses through the Hub Mode

stages (shown in bold). The remaining sub-sections provide more detail on each stage of operation.

TABLE 5-1:

MODES OF OPERATION

RESET_N Input

Summary

Standby Mode: This is the lowest power mode of the device. No functions are active

other than monitoring the

RESET_N input. All port interfaces are high impedance and

the PLL is halted. Refer to Section 8.12, Resets for additional information on

RESET_N.

Hub (Normal) Mode: The device operates as a configurable USB hub. This mode has

various sub-modes of operation, as detailed in Figure 5-1. Power consumption is based

on the number of active ports, their speed, and amount of data received.

FIGURE 5-1:

HUB MODE FLOWCHART

Combine OTP

Config Data

In SPI Mode

& Ext. SPI ROM

present?

YES

Run From

External SPI ROM

(SPI_INIT)

SMBus Slave Pull-ups?

RESET_N deasserted

Modify Config

Based on Config

Straps

(CFG_ROM)

Load Config from

Internal ROM

YES

(SMBUS_CHECK)

Perform SMBus/I

Initialization

SOC Done?

YES

(CFG_SMBUS)

(CFG_OTP)

Hub Connect

(USB_ATTACH)

Normal Operation

(NORMAL_MODE)

(CFG_STRAP)

Configuration 1?

YES

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