Datasheet

 2013 - 2015 Microchip Technology Inc. DS00001726B-page 17
USB2422
4.2.1.1 Hub Configuration Timing for Strapping Option
4.2.2 USB BUS RESET
In response to the upstream port signaling a reset to the hub, the hub does the following:
1. Sets default address to 0.
2. Sets configuration to unconfigured.
3. The PRTPWR power to downstream devices is turned on when battery charging is enabled for a specific port,
and removed when battery charging is disabled for a specific port.
4. Clears all TT buffers.
5. Moves device from suspended to active (if suspended).
6. Complies with Section 11.10 of the USB 2.0 Specification for behavior after completion of the reset sequence.
The host then configures the hub and the hub’s downstream port devices in accordance with the specification.
The hub does not propagate the upstream USB reset to downstream devices.
FIGURE 4-1: HUB CONFIGURATION TIMING
TABLE 4-2: HUB CONFIGURATION TIMING
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) 3 μsec
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
Note: All power supplies must have reached the operating levels mandated in Section 5.0, "DC Parameters",
prior to (or coincident with) the assertion of RESET_N.
t1
t4
t5
t6
t7 t8
Valid Driven by Hub if strap is an output
RESET_N
VSS
NON_REM[1:0]
VSS
Hardware
reset asserted
Read
NON_REM[1:0]
Drive Strap
Outputs to
inactive levels
Attach
USB
Upstream
Attach
Debounce
Interval Idle
Start completion
request response
t2
t3
Don’t Care
Don’t Care