USB3450-FZG SMSC [SMSC Corporation], USB3450-FZG Datasheet - Page 27

• Manufacturer Part Number: USB3450-FZG
• Description: HI-SPEED USB HOST OR DEVICE PHY WITH UTMI+INTERFACE
• Manufacturer: SMSC [SMSC Corporation]

Hi-Speed USB Host or Device PHY With UTMI+ Interface
Datasheet
Chapter 7 Application Notes
SMSC USB3450
7.1
7.2
MODE[1:0]
00
01
LS[1]
LINESTATE[1:0]
0
0
1
1
The following sections consist of select functional explanations to aid in implementing the USB3450
into a system. For complete description and specifications consult the Hi-Speed Transceiver Macrocell
Interface Specification and Universal Serial Bus Specification Revision 2.0.
The voltage thresholds that the LINESTATE[1:0] signals use to reflect the state of DP and DM depend
on the state of XCVRSELECT. LINESTATE[1:0] uses HS thresholds when the HS transceiver is
enabled (XCVRSELECT = 0) and FS thresholds when the FS transceiver is enabled (XCVRSELECT
= 1). There is not a concept of variable single-ended thresholds in the Hi-Speed specification for HS
mode.
The HS receiver is used to detect Chirp J or K, where the output of the HS receiver is always qualified
with the Squelch signal. If squelched, the output of the HS receiver is ignored. In the USB3450, as an
alternative to using variable thresholds for the single-ended receivers, the following approach is used.
In HS mode, 3ms of no USB activity (IDLE state) signals a reset. The Link monitors LINESTATE[1:0]
for the IDLE state. To minimize transitions on LINESTATE[1:0] while in HS mode, the presence of
Squelch
The OPMODE[1:0] pins allow control of the operating modes.
Linestate
OPMODES
STATE#
0
1
is used to force LINESTATE[1:0] to a J state.
LS[0]
0
1
0
1
Normal Operation
Non-Driving
STATE NAME
SE0
J
K
SE1
XCVRSELECT =1
TERMSELECT=1
FULL SPEED
Table 7.2 Operational Modes
Table 7.1 Linestate States
DATASHEET
Transceiver operates with normal USB data encoding and
decoding
Allows the transceiver logic to support a soft disconnect feature
which tri-states both the HS and FS transmitters, and removes
any termination from the USB making it appear to an upstream
port that the device has been disconnected from the bus
27
STATE OF DP/DM LINES
Squelch
Squelch
Invalid
Invalid
XCVRSELECT =0
TERMSELECT=0
HIGH SPEED
DESCRIPTION
Squelch
Squelch
HS Diff. Receiver Output
Squelch
HS Diff. Receiver Output
Invalid
XCVRSELECT =0
TERMSELECT=1
CHIRP MODE
Revision 0.1 (05-11-05)
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