Datasheet

USB 2.0 Hi-Speed Hub Controller
Datasheet
Revision 2.3 (06-11-13) 44 SMSC USB251xB/xBi
DATASHEET
5.5.1.2 RESET_N for EEPROM Configuration
Figure 5.4 Reset_N Timing for EEPROM Mode
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 t6+t7+t8+t9.
 All power supplies must have reached the operating levels mandated in Chapter 6: DC Parameters,
prior to (or coincident with) the assertion of RESET_N.
NAME DESCRIPTION MIN TYP MAX UNITS
t1 RESET_N asserted 1 μs
t2 CFG_SEL[1:0] setup time 16.7 ns
t3 CFG_SEL[1:0] hold time 16.7 1400 ns
t4 Hub recovery/stabilization 500
μs
t5 EEPROM read (hub configuration) 2.0 99.5 ms
t6 USB attach (see notes) 100 ms
t7 Host acknowledges attach and signals USB reset 100 ms
t8 USB idle undefined ms
t9 Completion time for requests (with or without data
stage)
5ms
t1
t5
t7 t8 t9
RESET_N
VSS
Hardware reset
asserted
Read I
2
C
EEPROM
Attach USB
upstream
USB reset
recovery
Idle
Start completion
request response
Read
CFG_SEL[1:0]
t2
t3
t6
valid
CFG_SEL[2:0]
VSS
don’t care don’t care
t4