Datasheet

 2010 - 2015 Microchip Technology Inc. DS00001692C-page 37
USB251xB/xBi
5.5.1.2 RESET_N for EEPROM Configuration
Note 5-2 10 ms for hubs, 50 ms for root ports.
FIGURE 5-2: RESET_N TIMING FOR EEPROM MODE
Name Description MIN TYP MAX Units
t1 RESET_N asserted 1 s
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
s
t5 EEPROM read (hub configuration) 40 ms
t6 USB attach (see notes) 40 ms
t7 Host acknowledges attach and signals USB reset 100 ms
t8 USB_RESET host-
defined
ms
t9 USB_RESET state Note 5-2 ms
t10 USB Reset Recovery 10 ms
Note:
• 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 Section 6.0, "DC Parameters", prior to
(or coincident with) the assertion of RESET_N.
t1
t5
t7 t8 t9
RESET_N
VSS
Hardware reset
asserted
Read I
2
C
EEPROM
Attach USB
upstream
Attach
Debounce
Interval
USB_RESET
USB_RESET
State
Read
CFG_SEL[1:0]
t2
t3
t6
valid
CFG_SEL[2:0]
VSS
don’t care don’t care
t4
t10
USB Reset
Recovery