USB3500 SMSC Corporation, USB3500 Datasheet - Page 31

• Manufacturer Part Number: USB3500
• Description: Hi-Speed USB Host
• Manufacturer: SMSC Corporation

Hi-Speed USB Host, Device or OTG PHY With UTMI+ Interface
Datasheet
Chapter 7 Application Notes
SMSC USB3500
7.1
LINESTATE[1:0]
LS[1]
0
0
LS[1]
LINESTATE[1:0]
0
0
1
1
LS[0]
The following sections consist of select functional explanations to aid in implementing the USB3500
into a system. For complete description and specifications consult the USB2.0 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 USB2.0 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 USB3500, as an
alternative to using variable thresholds for the single-ended receivers, the following approach is used.
In HS device 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 is used to force LINESTATE[1:0] to a J state.
Linestate
0
1
XCVRSEL[1:0]=10
LS[0]
TERMSELECT=1
0
1
0
1
LOW SPEED
Table 7.1 Device Linestate States (DPPD & DMPD = 0)
LS-K
SE0
Table 7.2 Host Linestate States (DPPD & DMPD = 1)
XCVRSELECT[1:0]=01
TERMSELECT=1
FULL SPEED
FS-K
FS-J
SE0
SE1
XCVRSEL[1:0]=01
TERMSELECT=1
FULL SPEED
DATASHEET
FS-J
SE0
STATE OF DP/DM LINES
31
STATE OF DP/DM LINES
XCVRSELECT[1:0]=00
TERMSELECT=0
HIGH SPEED
!Squelch
Squelch
XCVRSEL[1:0]=00
Invalid
Invalid
TERMSELECT=0
OPMODE=00/01
HIGH SPEED
!Squelch
Squelch
!HS Differential Receiver
HS Differential Receiver
XCVRSELECT[1:0]=00
TERMSELECT=1
CHIRP MODE
XCVRSEL[1:0]=00
TERMSELECT=0
Revision 1.0 (04-04-05)
Receiver Output
!Squelch &
!Squelch &
CHIRP MODE
HS Differential
OPMODE=10
Squelch
Output
Output
Invalid
!Squelch &
Squelch