Hi-Speed USB Host or Device PHY With UTMI+ Interface

Datasheet

Revision 0.1 (05-11-05)

28

SMSC USB3450

DATASHEET

The OPMODE[1:0] signals are normally changed only when the transmitter and the receiver are

quiescent, i.e. when entering a test mode or for a device initiated resume.

When using OPMODE[1:0] = 10 the SYNC and EOP patterns are not transmitted.

The only exception to this is when OPMODE[1:0] is set to state 2 while TXVALID has been asserted

(the transceiver is transmitting a packet), in order to flag a transmission error. In this case, the

USB3450 has already transmitted the SYNC pattern so upon negation of TXVALID the EOP must also

be transmitted to properly terminate the packet. Changing the OPMODE[1:0] signals under all other

conditions, while the transceiver is transmitting or receiving data will generate undefined results.

7.3

Test Mode Support

7.4

SE0 Handling

For FS operation, IDLE is a J state on the bus. SE0 is used as part of the EOP or to indicate reset.

When asserted in an EOP, SE0 is never asserted for more than 2 bit times. The assertion of SE0 for

more than 2.5us is interpreted as a reset by the device operating in FS mode.

For HS operation, IDLE is a SE0 state on the bus. SE0 is also used to reset a HS device. A HS

device cannot use the 2.5us assertion of SE0 (as defined for FS operation) to indicate reset since the

bus is often in this state between packets. If no bus activity (IDLE) is detected for more than 3ms, a

HS device must determine whether the downstream facing port is signaling a suspend or a reset. The

following section details how this determination is made. If a reset is signaled, the HS device will then

initiate the HS Detection Handshake protocol.

7.5

Reset Detection

If a device in HS mode detects bus inactivity for more than 3ms (T1), it reverts to FS mode. This

enables the FS pull-up on the DP line in an attempt to assert a continuous FS J state on the bus. The

Link must then check LINESTATE for the SE0 condition. If SE0 is asserted at time T2, then the

upstream port is forcing the reset state to the device (i.e., a Driven SE0). The device will then initiate

the HS detection handshake protocol.

10

2

Disable Bit Stuffing

and NRZI encoding

Disables bitstuffing and NRZI encoding logic so that 1's loaded

from the DATA bus become 'J's on the DP/DM and 0's become

'K's

11

3

Reserved

N/A

Table 7.3 Hi-Speed Test Modes

HI-SPEED TEST MODES

USB3450 SETUP

OPERATIONAL MODE

LINK TRANSMITTED

DATA

XCVRSELECT &

TERMSELECT

SE0_NAK

State 0

No transmit

HS

J

State 2

All '1's

HS

K

State 2

All '0's

HS

Test_Packet

State 0

Test Packet data

HS

Table 7.2 Operational Modes (continued)

MODE[1:0]

STATE#

STATE NAME

DESCRIPTION