USB2512I SMSC Corporation, USB2512I Datasheet - Page 30

• Manufacturer Part Number: USB2512I
• Description: Industrial Temperature Rated USB 2.0 High-Speed 2-Port Hub Controller
• Manufacturer: SMSC Corporation

Revision 1.92 (11-28-07)
4.6.2.3
4.6.3
NAME
RESET_N
t1
t2
t3
t4
t5
t6
t7
VSS
Hardware
asserted
reset
RESET_N Asserted.
Hub Recovery/Stabilization.
SMBus Code Load (See Note).
Hub Configuration and USB Attach.
Host acknowledges attach and signals USB
Reset.
USB Idle.
Completion time for requests (with or without data
stage).
RESET_N for SMBus Slave Configuration
Notes:
USB Bus Reset
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[2:1] to all downstream ports.
For Bus-Powered configurations, the 99.5ms (MAX) is required, and the Hub and its associated
circuitry must not consume more than 100mA 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
Parameters, prior to (or coincident with) the assertion of RESET_N.
t1
Negation
Reset
DESCRIPTION
Figure 4.5 Reset_N Timing for SMBus Mode
Table 4.5 Reset_N Timing for SMBus Mode
SMBus Code
t2
Load
DATASHEET
Stabilization
t3
Hub PHY
Industrial Temperature Rated USB 2.0 High-Speed 2-Port Hub Controller
30
t4
Upstream
Attach
USB
MIN
100
1
USB Reset
recovery
t5
Undefined
TYP
250
t6
Idle
Chapter 5, DC
MAX
500
300
100
5
t7
completion
SMSC USB2512i
response
request
Start
UNITS
Datasheet
msec
msec
msec
msec
msec
μsec
μsec