USB2.0 PHY IC
Chapter 4 Interface Signal Definition
Table 4.1 System Interface Signals
ACTIVE
NAME
RESET
DIRECTION
LEVEL
DESCRIPTION
Input
High
Reset. Reset all state machines. After coming out of reset, must
wait 5 rising edges of clock before asserting TXValid for transmit.
Assertion of Reset: May be asynchronous to CLKOUT
De-assertion of Reset: Must be synchronous to CLKOUT
XCVRSELECT
TERMSELECT
SUSPENDN
Input
Input
Input
N/A
N/A
Low
Transceiver Select. This signal selects between the FS and HS
transceivers:
0: HS transceiver enabled
1: FS transceiver enabled.
Termination Select. This signal selects between the FS and HS
terminations:
0: HS termination enabled
1: FS termination enabled
Suspend. Places the transceiver in a mode that draws minimal
power from supplies. Shuts down all blocks not necessary for
Suspend/Resume operation. While suspended, TERMSELECT
must always be in FS mode to ensure that the 1.5k Ω pull-up on
DP remains powered.
0: Transceiver circuitry drawing suspend current
1: Transceiver circuitry drawing normal current
CLKOUT
Output
Input
Rising Edge System Clock. This output is used for clocking receive and
transmit parallel data at 60MHz (8-bit mode) or 30MHz (16-bit
mode). When in 8-bit mode, this specification refers to CLKOUT
as CLK60. When in 16-bit mode, CLKOUT is referred to as
CLK30.
OPMODE[1:0]
N/A
Operational Mode. These signals select between the various
operational modes:
[1] [0] Description
0
0
1
1
0
1
0
1
0: Normal Operation
1: Non-driving (all terminations removed)
2: Disable bit stuffing and NRZI encoding
3: Reserved
LINESTATE[1:0]
DATABUS16_8
Output
Input
N/A
Line State. These signals reflect the current state of the USB
data bus in FS mode, with [0] reflecting the state of DP and [1]
reflecting the state of DM. When the device is suspended or
resuming from a suspended state, the signals are combinatorial.
Otherwise, the signals are synchronized to CLKOUT.
[1] [0] Description
0
0
1
1
0
1
0
1
0: SE0
1: J State
2: K State
3: SE1
N/A
Databus Select. Selects between 8-bit and 16-bit data transfers.
0: 8-bit data path enabled. VALIDH is undefined. CLKOUT =
60MHz.
1: 16-bit data path enabled. CLKOUT = 30MHz.
Revision 1.3 (10-05-04)
5
SMSC GT3200, SMSC USB3250
DATASHEET
SMSC [ SMSC CORPORATION ]
