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Pin description tables, Table 1 system interface pins, Product preview – SMSC USB3250 User Manual

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Hi-Speed USB Device Transceiver with UTMI Interface

SMSC USB3250

5

Revision 1.7 (05-11-07)

PRODUCT PREVIEW

Pin Description Tables

Table 1 System Interface Pins

NAME

DIRECTION

ACTIVE

LEVEL

DESCRIPTION

RESET

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 unless

RESET is asserted longer than two periods of CLKOUT.

XCVRSELECT

Input

N/A

Transceiver Select. This signal selects between the FS and HS

transceivers:

0: HS transceiver enabled

1: FS transceiver enabled.

TERMSELECT

Input

N/A

Termination Select. This signal selects between the FS and HS

terminations:

0: HS termination enabled

1: FS termination enabled

SUSPENDN

Input

Low

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

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]

Input

N/A

Operational Mode. These signals select between the various

operational modes:

[1] [0] Description

0 0 0: Normal Operation

0 1 1: Non-driving (all terminations removed)

1 0 2: Disable bit stuffing and NRZI encoding

1 1 3: Reserved

LINESTATE[1:0]

Output

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 0: SE0

0 1 1: J State

1 0 2: K State

1 1 3: SE1

DATABUS16_8

Input

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.