USB3450 datasheet(35/40 Pages) SMSC

35 / 40 page

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

Datasheet

SMSC USB3450

Revision 0.1 (05-11-05)

DATASHEET

Notes:

■

T0 may be up to 4ms after HS Reset T0.

■

The Link must use LINESTATE to detect the downstream port chirp sequence.

■

Due to the assertion of the HS termination on the host port and FS termination on the device port,

between T1 and T7 the signaling levels on the bus are higher than HS signaling levels and are

less than FS signaling levels.

7.10

HS Detection Handshake – Suspend Timing

If reset is entered from a suspended state, the internal oscillator and clocks of the transceiver are

assumed to be powered down. Figure 7.6 shows how CLKOUT is used to control the duration of the

chirp generated by the device.

When reset is entered from a suspended state (J to SE0 transition reported by LINESTATE),

SUSPENDN is combinatorially negated at time T0 by the Link. It takes approximately 5 milliseconds

for the transceiver's oscillator to stabilize. The device does not generate any transitions of the CLKOUT

signal until it is “usable” (where “usable” is defined as stable to within ±10% of the nominal frequency

and the duty cycle accuracy 50±5%).

The first transition of CLKOUT occurs at T1. The Link then sets OPMODE to Disable Bit Stuffing and

NRZI encoding, XCVRSELECT to HS mode, and must assert a Chirp K for 66000 CLKOUT cycles to

ensure a 1ms minimum duration. If CLKOUT is 10% fast (66MHz) then Chirp K will be 1.0ms. If

CLKOUT is 10% slow (54 MHz) then Chirp K will be 1.2ms. The 5.6ms requirement for the first

CLKOUT transition after SUSPENDN, ensures enough time to assert a 1ms Chirp K and still complete

before T3. Once the Chirp K is completed (T3) the Link can begin looking for host chirps and use

CLKOUT to time the process. At this time, the device follows the same protocol as in Section 7.9, "HS

Detection Handshake – HS Downstream Facing Port" for completion of the High Speed Handshake.

Figure 7.6 HS Detection Handshake Timing Behavior from Suspend

CLK60

Look for host chirps

Device Chirp K

SUSPENDN

DP/DM

TERMSELECT

TXVALID

SE0

CLK power up time

XCVRSELECT

OPMODE 1

OPMODE 0

time

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