USB2502

DS000002248A-page 26

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5.6.1.1

RESET_N for Strapping Option Configuration

Note 1:

When in Bus-Powered mode, the Hub and its associated circuitry must not consume more than 100mA from

the upstream USB power source during t1+t5.

2:

All Power Supplies must have reached the operating levels mandated in Section 7.0, "DC Parameters", prior

to (or coincident with) the assertion of RESET_N.

FIGURE 5-2:

RESET_N TIMING FOR DEFAULT/STRAP OPTION MODE

TABLE 5-5:

RESET_N TIMING FOR DEFAULT/STRAP OPTION MODE

Name

Description

MIN

TYP

MAX

Units

t1

RESET_N Asserted.

1

sec

t2

Strap Setup Time

16.7

nsec

t3

Strap Hold Time.

16.7

1400

nsec

t4

hub outputs driven to inactive logic states

2.0

1.5

sec

t5

USB Attach (See Note).

100

msec

t6

Host acknowledges attach and signals USB Reset.

100

msec

t7

USB Idle.

undefined

msec

t8

Completion time for requests (with or without data

stage).

5msec

t1

t4

t5

t6

t7

t8

Valid

Don’t Care

Don’t Care

Driven by Hub if strap is an output.

RESET_N

VSS

Strap Pins

VSS

Hardware

reset

asserted

Read Strap

Options

Drive Strap

Outputs to

inactive

levels

Attach

USB

Upstream

USB Reset

recovery

Idle

Start

completion

request

response

t2

t3