GT3200 datasheet(42/51 Pages) SMSC

42 / 51 page

USB2.0 PHY IC

Revision 1.3 (10-05-04)

SMSC GT3200, SMSC USB3250

DATASHEET

8.11

Assertion of Resume

In this case, an event internal to the device initiates the resume process. A device with remote wake-

up capability must wait for at least 5ms after the bus is in the idle state before sending the remote

wake-up resume signaling. This allows the hubs to get into their suspend state and prepare for

propagating resume signaling.

The device has 10ms where it can draw a non-suspend current before it must drive resume signaling.

At the beginning of this period the SIE may negate SUSPENDN, allowing the transceiver (and its

oscillator) to power up and stabilize.

Figure 8.7 illustrates the behavior of a device returning to HS mode after being suspended. At T4, a

device that was previously in FS mode would maintain TERMSELECT and XCVRSELECT high.

To generate resume signaling (FS 'K') the device is placed in the "Disable Bit Stuffing and NRZI

encoding" Operational Mode (OPMODE [1:0] = 10), TERMSELECT and XCVRSELECT must be in FS

mode, TXVALID asserted, and all 0's data is presented on the TXDATA bus for at least 1ms (T1 - T2).

Figure 8.7 Resume Timing Behavior (HS Mode)

Table 8.9 Resume Timing Values (HS Mode)

TIMING

PARAMETER

DESCRIPTION

VALUE

Internal device event initiating the resume process

0 (reference)

Device asserts FS 'K' on the bus to signal resume

request to downstream port

T0 < T1 < T0 + 10ms.

The device releases FS 'K' on the bus. However by

this time the 'K' state is held by downstream port.

T1 + 1.0ms < T2 < T1 + 15ms

Downstream port asserts SE0.

T1 + 20ms

Latest time at which a device, which was previously

in HS mode, must restore HS mode after bus activity

stops.

T3 + 1.33µs {2 Low-speed bit

times}

TXVALID

T3 T4

'K' State

FS Idle ('J')

SUSPENDN

DP/DM

XCVRSELECT &

TERMSELECT

SE0

FS Mode

HS Mode

time

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