Hi-Speed USB Device PHY with UTMI Interface

Datasheet

8.11Assertion of Resume

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

 

 

 

T0

Internal device event initiating the resume

0 (reference)

 

process

 

 

 

 

 

 

T1

Device asserts FS 'K' on the bus to signal

T0

< T1 < T0 + 10ms.

 

resume request to downstream port

 

 

 

 

 

 

T2

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

T1

+ 1.0ms < T2 < T1 + 15ms

 

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

 

 

 

port.

 

 

 

 

 

T3

Downstream port asserts SE0.

T1 + 20ms

 

 

 

 

T4

Latest time at which a device, which was

T3

+ 1.33µs {2 Low-speed bit times}

 

previously in HS mode, must restore HS mode

 

 

 

after bus activity stops.

 

 

 

 

 

 

Revision 1.5 (11-15-07)

38

SMSC USB3280

 

DATASHEET