gt3200 SMC Corporation, gt3200 Datasheet - Page 35

• Manufacturer Part Number: gt3200
• Description: Usb2.0 Phy Ic
• Manufacturer: SMC Corporation

USB2.0 PHY IC
SMSC GT3200, SMSC USB3250
8.7
TERMSELECT
XCVRSELECT
SUSPENDN
PARAMETER
HS Reset T0
TIMING
DP/DM
T1
T2
T3
T4
SIE must then check LINESTATE for the J condition. If J is asserted at time T2, then the upstream
port is asserting a soft SE0 and the USB is in a J state indicating a suspend condition. By time T4
the device must be fully suspended.
The High Speed Detection Handshake process is entered from one of three states: suspend, active
FS or active HS. The downstream facing port asserting an SE0 state on the bus initiates the HS
Detection Handshake. Depending on the initial state, an SE0 condition can be asserted from 0 to 4
ms before initiating the HS Detection Handshake. These states are described in the USB2.0
specification.
There are three ways in which a device may enter the HS Handshake Detection process:
time
HS Detection Handshake
Activity
Last
x x x x x x x
x x x x x x x
x x x x x x x
T0
End of last bus activity, signaling either a reset or
a SUSPEND.
The time at which the device must place itself in
FS mode after bus activity stops.
SIE samples LINESTATE. If LINESTATE = 'J', then
the initial SE0 on the bus (T0 - T1) had been due
to a Suspend state and the SIE remains in HS
mode.
The earliest time where a device can issue
Resume signaling.
The latest time that a device must actually be
suspended, drawing no more than the suspend
current from the bus.
Figure 8.2 Suspend Timing Behavior (HS Mode)
Soft SE0
Table 8.5 Suspend Timing Values (HS Mode)
DESCRIPTION
T1
DATASHEET
T2
30
T3
'J' State
0 (reference)
HS Reset T0 + 3. 0ms < T1 <
HS Reset T0 + 3.125ms
T1 + 100 µs < T2 < T1 + 875µs
HS Reset T0 + 5ms
HS Reset T0 + 10ms
VALUE
T4
Revision 1.3 (10-05-04)
Device is suspended