Huawei ME909u-521 manual UART and Sleep, Module Wake-up, Host Woken up by Module, Wake-up Source

HUAWEI ME909u-521 LTE LGA Module
Application Guide	Sleeping and Waking Up Application Scenarios

Note:

If the USB driver used is developed by users or is integrated with external application, ensure that the USB driver supports the USB suspend features (including selective suspend and global suspend, as defined in the USB standard.)

8.3.3UART and Sleep

UART is an important communication channel between the module and the host. If the host uses UART (a TTL level Interface), it can connect to the module's UART directly. If the host uses RS232, it can connect to the module's UART through a conversion chip such as MAX232.

Note:

If the module is in sleep state, the host send data to module only by UART that can’t wakeup the module. It must be used with WAKEUP_IN pin.

8.3.4Module Wake-up

RF periodically wakes up the module based on the DRX cycle (depending on the actual configuration of the network system), as shown in ‎Figure 8-5 .

Other aperiodic events include:

1.The host sends data using USB or pulls WAKEUP_IN up.

2.Changes on the network, for example, an incoming call, an incoming text message, a signal change, a network working mode change, a network search, an IP data package (when a dial-up network connection is set up).

3.Software system events such as a timer

4.Abnormal events, for example, an antenna drops or a SIM card becomes loose.

8.3.5Host 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.

Issue 01 (2013-07-05)	Huawei Proprietary and Confidential	57
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