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HUAWEI ME909u-521 LTE LGA Module
Application Guide
Sleeping and Waking Up Application Scenarios
Issue 01 (2013-07-05)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
58
2. The USB driver enables or disables remote wake-up by executing
SET_FEATURE and CLEAR_FEATURE commands. Therefore, remote wake-up
must be enabled on the USB driver before USB enters suspended mode.
3. When the host receives the remote wake-up signal from the module, the host
needs to send a full speed K signal that lasts at least 20 ms. When the USB
controller resumes, the host must send the SOF token within 3 ms from the
startup of the idle state. Otherwise, the module enters suspended mode again,
as shown in Figure 8-7 .
Figure 8-7 USB resume time sequence
FS idle FSK HS idle uSOF
D+
D-
HS HubHS Device
Start of
Resume
Signaling
3ms
Device sees
first activity
Start of
Resume
Signaling
>20ms
<3.0ms
Signaling
Signaling
<1.33us
Device
Resumed
if remote
wake up
Figure 8-8 Successful procedure of remote wake-up
WAKEUP_OUT Waking up the Host
The module will output a 1s pulse using WAKE# as shown in Figure 8-1 or
WAKEUP_OUT as shown in Figure 8-2 when a wake-up source arrives. The host
wakes itself up after detecting the level change.