USB2517 Standard Microsystems Corp., USB2517 Datasheet - Page 58

• Manufacturer Part Number: USB2517
• Description: Usb 2.0 Hi-speed Hub Controller
• Manufacturer: Standard Microsystems Corp.

Revision 1.0 (3-11-09)
8.6.1.3
RESET_N
8.6.2
NAME
t1
t2
t3
t4
t5
t6
t7
VSS
Hardware
asserted
reset
RESET_N Asserted.
Hub Recovery/Stabilization.
SMBus Code Load (See Note).
Hub Configuration and USB Attach.
Host acknowledges attach and signals USB
Reset.
USB Idle.
Completion time for requests (with or without data
stage).
RESET_N for SMBus Slave Configuration
Notes:
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.
1. Sets default address to 0.
2. Sets configuration to: Unconfigured.
3. Negates PRTPWR[x:1] to all downstream ports unless battery charging (BC_EN) is enabled.
4. Clears all TT buffers.
5. Moves device from suspended to active (if suspended).
For bus-powered configurations, the 99.5 ms (MAX) is required, and the hub and its associated
circuitry must not consume more than 100 mA from the upstream USB power source during
t2+t3+t4+t5+t6+t7. For Self-Powered configurations, t3 MAX is not applicable and the time to load
the configuration is determined by the external SMBus host.
All power supplies must have reached the operating levels mandated in
prior to (or coincident with) the assertion of RESET_N.
t1
Negation
Reset
DESCRIPTION
Figure 8.5 Reset_N Timing for SMBus Mode
Table 8.9 Reset_N Timing for SMBus Mode
SMBus Code
t2
Load
Stabilization
t3
Hub PHY
DATASHEET
58
t4
Upstream
Attach
USB
MIN
100
1
USB Reset
recovery
t5
Undefined
TYP
250
USB 2.0 Hi-Speed Hub Controller
Chapter 9, DC
t6
Idle
MAX
500
300
100
5
t7
SMSC USB251x
completion
response
Parameters,
request
Start
UNITS
Datasheet
msec
msec
msec
msec
msec
μsec
μsec