Datasheet

USB 2.0 Hi-Speed Hub Controller
Datasheet
Revision 1.1 (04-26-10) 58 SMSC USB251x
DATASHEET
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 t1+t5.
 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.
8.7.1.2 RESET_N for EEPROM Configuration
Figure 8.7 Reset_N Timing for EEPROM Mode
Table 8.8 Reset_N Timing for Default/Strap Option Mode
NAME DESCRIPTION MIN TYP MAX UNITS
t1 RESET_N Asserted. 1 μsec
t2 Strap Setup Time 16.7 nsec
t3 Strap Hold Time. 16.7 1400 nsec
t4 hub outputs driven to inactive logic states 1.5 2 μsec
t5 USB Attach (See Note). 100 msec
t6 Host acknowledges attach and signals USB
Reset.
100 msec
t7 USB Idle. undefined msec
t8 Completion time for requests (with or without data
stage).
5 msec
Table 8.9 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
t1
t2
t4
t5
t6 t7
RESET_N
VSS
Hardware
reset
asserted
Read Strap
Options
Read EEPROM
+
Set Options
Attach
USB
Upstream
USB Reset
recovery
Idle
Start
completion
request
response
t3