Справочник Пользователя для SMSC USB2513B

USB 2.0 Hi-Speed Hub Controller

Revision 1.0 (3-11-09)

58

SMSC USB251x

„

For bus-powered configurations, the 99.5 ms (MAX) is required, and the hub and its associated 
circuitry must not consume more than 100 mA from the upstream USB power source during 
t2+t3+t4+t5+t6+t7. For Self-Powered configurations, t3 MAX is not applicable and the time to load 
the configuration is determined by the external SMBus host.

„

All power supplies must have reached the operating levels mandated in 

, 

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

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

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

1. Sets default address to 0.

2. Sets configuration to: Unconfigured.

3. Negates PRTPWR[x:1] to all downstream ports unless battery charging (BC_EN) is enabled.

4. Clears all TT buffers.

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

t1

RESET_N Asserted.

1

μsec

t2

Hub Recovery/Stabilization.

500

μsec

t3

SMBus Code Load (See Note).

250

300

msec

t4

Hub Configuration and USB Attach.

100

msec

t5

Host acknowledges attach and signals USB 

Reset.

100

msec

t6

USB Idle.

Undefined

msec

t7

Completion time for requests (with or without data 

stage).

5

msec

t1

t2

t4

t5

t6

t7

RESET_N

VSS

Hardware 

reset 

asserted

Reset 

Negation

SMBus Code 

Load

Attach 

USB 

Upstream

USB Reset 

recovery

Idle

Start 

completion 

request 

response

t3

Hub PHY 

Stabilization