HUAWEI ME909u-523 LTE LGA Module
Application Guide
Sleeping and Waking Up Application Scenarios
Issue 04 (2014-12-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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8.3.5
Host Woken up by Module
Wake-up Source
A wake-up source is a module event that can wake up the host, for example, an
incoming voice call, a text message, data (PPP data, TCP/UDP data from the
network), and unsolicited messages.
Remotely Waking up the Host Using USB
When the host is in sleep mode and the USB controller is in suspended mode, if the
module needs to send data to the host (for example, a wake-up source has arrived),
the module sends a remote wake-up signal that lasts 3 ms to inform the host to start
USB resume (as shown in Figure 8-7 ). To complete the procedure, the following
conditions must be met:
1. The USB controller on the host supports USB remote wake-up and can wake up
the host.
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-
H
S
H
u
b
H
S
D
ev
ic
e
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