USB2412 Ver la hoja de datos (PDF) - SMSC -> Microchip

Número de pieza

componentes Descripción

fabricante

USB2412

2-Port USB 2.0 Hi-Speed Hub Controller

SMSC -> Microchip 

2-Port USB 2.0 Hi-Speed Hub Controller

Datasheet

3.2.1.1

RESET_N

Hardware

reset asserted

Read

NON_REM[1:0]

p

Outputs to

USB

inactive levels Upstream

USB Reset

recovery

Start completion

Idle request response

t1

t5

t2

t3

RESET_N

t6

t7

t8

VSS

t4

NON_REM[1:0]

VSS

Don’t Care

Valid

Don’t Care

Driven by Hub if strap is an output

Figure 3.1 Reset_N Timing

Table 3.1 Reset_N Timing

NAME

DESCRIPTION

t1

RESET_N asserted

t2

Strap setup time

t3

Strap hold time

t4

Hub outputs driven to inactive logic states

t5

USB attach (See Note)

t6

Host acknowledges attach and signals USB reset

t7

USB idle

t8

Completion time for requests (with or without data

stage)

MIN

1

16.7

16.7

100

TYP

1.5

undefined

MAX

1400

2

100

5

UNITS

μsec

nsec

nsec

μsec

msec

msec

msec

msec

Note: All power supplies must have reached the operating levels mandated in Chapter 4, DC

Parameters, prior to (or coincident with) the assertion of RESET_N.

3.2.2 USB Bus Reset

In response to the upstream port signaling a reset to the hub, the hub does the following:

1. Sets default address to 0.

2. Sets configuration to unconfigured.

3. Negates PRTPWR[2:1] to all downstream ports.

4. Clears all TT buffers.

5. Moves device from suspended to active (if suspended).

6. Complies with Section 11.10 of the USB 2.0 Specification for behavior after completion of the reset

sequence. The host then configures the hub and the hub’s downstream port devices in accordance

with the specification.

Note: The hub does not propagate the upstream USB reset to downstream devices.

SMSC USB2412

15

DATASHEET

Revision 1.3 (12-27-11)

Share Link: