USB MultiSwitchTM Hub
Datasheet
9.1.1.3
RESET_N for SMBus Slave Configuration
Start
completion
request
Hardware
reset
asserted
Attach
USB
Upstream
Reset
SMBus Code
Load
Hub PHY
USB Reset
recovery
Idle
Negation
Stabilization
response
t6
t7
t1
t5
t2
t3
t4
RESET_N
VSS
Figure 9.3 Reset_N Timing for SMBus Mode
Table 9.3 Reset_N Timing for SMBus Mode
NAME
DESCRIPTION
MIN
TYP
MAX
UNITS
t1
t2
t3
t4
t5
RESET_N Asserted.
1
μsec
μsec
msec
msec
msec
Hub Recovery/Stabilization.
SMBus Code Load (See Note 9.3)
Hub Configuration and USB Attach.
500
300
100
250
Host acknowledges attach and signals USB
Reset.
100
t6
t7
USB Idle.
Undefined
msec
msec
Completion time for requests (with or without data
stage).
5
Note: For Bus-Powered configurations, the Hub and its associated circuitry will consume more than
100mA from the upstream USB power source during t2+t3+t4+t5+t6+t7.
Note 9.3 For Self-Powered configurations, t3 MAX is not applicable and the time to load the
configuration is determined by the external SMBus host.
9.1.2
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.
Sets default address to 0.
Sets configuration to: Unconfigured.
Negates PRTPWR[4:1] to all downstream ports.
Clears all TT buffers.
Moves device from suspended to active (if suspended).
Revision 1.91 (08-22-07)
SMSC USB2524
DATA5S0HEET
SMSC [ SMSC CORPORATION ]
