USB 2.0 Hi-Speed Hub Controller

Datasheet

8.6.1.2RESET_N for EEPROM Configuration

Hardware

 

Read EEPROM

Attach

 

 

Start

Read Strap

USB Reset

 

completion

reset

+

USB

Idle

Options

recovery

request

asserted

Set Options

Upstream

 

 

 

 

response

 

 

 

 

 

 

t1

 

t4

t5

t6

t7

t2

t3

RESET_N

VSS

Figure 8.4 Reset_N Timing for EEPROM Mode

Table 8.8 Reset_N Timing for EEPROM Mode

NAME

DESCRIPTION

MIN

TYP

MAX

UNITS

 

 

 

 

 

 

t1

RESET_N Asserted.

1

 

 

μsec

 

 

 

 

 

 

t2

Hub Recovery/Stabilization.

 

 

500

μsec

 

 

 

 

 

 

t3

EEPROM Read / Hub Config.

 

2.0

99.5

msec

 

 

 

 

 

 

t4

USB Attach (See Note).

 

 

100

msec

 

 

 

 

 

 

t5

Host acknowledges attach and signals USB

100

 

 

msec

 

Reset.

 

 

 

 

 

 

 

 

 

 

t6

USB Idle.

 

undefined

 

msec

 

 

 

 

 

 

t7

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 t4+t5+t6+t7.

„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.

SMSC USB251x

57

Revision 1.0 (3-11-09)

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