USB 2.0 Hi-Speed Hub Controller

Datasheet

8.6.1.1RESET_N for Strapping Option Configuration

Hardware

 

Drive Strap

Attach

 

 

Start

Read Strap

Outputs to

USB Reset

 

completion

reset

USB

Idle

Options

inactive

recovery

request

asserted

Upstream

 

 

levels

 

 

response

 

 

 

 

 

t1 t5 t6 t7 t8 t2

RESET_N

t3

VSS

 

 

t4

 

 

 

 

 

 

 

 

 

 

 

Strap Pins

 

 

 

 

 

 

 

 

Don’t Care

Valid

Don’t Care

Driven by Hub if strap is an output.

 

VSS

 

 

 

 

 

 

 

 

 

Figure 8.3 Reset_N Timing for Default/Strap Option Mode

 

 

 

 

Table 8.7 Reset_N Timing for Default/Strap Option Mode

 

 

NAME

 

DESCRIPTION

MIN

TYP

MAX

UNITS

t1

RESET_N Asserted.

 

1

 

 

μsec

t2

Strap Setup Time

 

16.7

 

 

nsec

t3

Strap Hold Time.

 

16.7

 

1400

nsec

t4

hub outputs driven to inactive logic states

 

1.5

2

μsec

t5

USB Attach (See Note).

 

 

 

100

msec

t6

Host acknowledges attach and signals USB

100

 

 

msec

 

Reset.

 

 

 

 

 

 

t7

USB Idle.

 

 

 

undefined

 

msec

t8

Completion time for requests (with or without data

 

 

5

msec

 

stage).

 

 

 

 

 

 

Notes:

„When in bus-powered mode, the hub and its associated circuitry must not consume more than 100 mA from the upstream USB power source during t1+t5.

„All power supplies must have reached the operating levels mandated in Chapter 9, DC Parameters, prior to (or coincident with) the assertion of RESET_N.

Revision 1.0 (3-11-09)

56

SMSC USB251x

DATASHEET