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HUAWEI ME936 LTE M.2 Module
Hardware Guide
Description of the Application Interfaces
Issue 03 (2017-12-11)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
39
The ESD protection component should choose low capacitance. The capacitance
of the component should
be
less than 10 pF.
To meet the requirements of 3GPP TS 51.010-1 protocols and electromagnetic
compatibility (EMC) authentication, the USIM socket should be placed near the
M.2 interface (it is recommended that the PCB circuit connects the M.2 interface
and the USIM socket does not exceed 100 mm), because a long circuit may lead
to wave distortion, thus affecting signal quality.
It is recommended that you wrap the area adjacent to the SIM_CLK and
SIM_DATA signal wires with ground. The Ground pin of the USIM socket and the
Ground pin of the USIM card must be well connected to the power Ground pin
supplying power to the ME936 module.
A 100 nF capacitor (0402 package is recommended so that larger capacitance
such as 1 uF can be employed if necessary) and a 33 pF capacitor are placed
between the SIM_PWR and Ground pins in parallel. Two 33 pF capacitors are
respectively placed between the SIM_DATA and Ground pins, the SIM_RST and
Ground pins. And one 68 pF capacitor is placed between the SIM_CLK and
Ground pins in parallel to filter interference from RF signals.
It is recommended to take electrostatic discharge (ESD) protection measures near
the USIM card socket. Transient voltage suppressor diode should be placed as
close as possible to the USIM socket, and the Ground pin of the ESD protection
component is well connected to the power Ground pin that supplies power to the
ME936 module.
3.7 Tunable Antenna Control
Huawei M.2 module provides the tunable antenna function, which uses relevant
GPIO interfaces to match the impedance of antenna and transmitter.
According to customer's requirement, Huawei M.2 module provides the tunable
antenna solution. The solution contains two parts: hardware section and software
section.
3.7.1
Hardware section
Huawei M.2 module provides four GPIO interfaces, which can be set to output high or
low level in accordance with the customer's requirement. Through different output
levels of four GPIO interfaces, the host can implement tuning the antenna efficiency.
3.7.2
Software section
Huawei M.2 module provides an AT command interface. Customers can use the AT
command interface to tune the antenna efficiency and get the configuration of
different bands. These configurations can be written into the firmware of the module.
The module will control the output level of GPIO interfaces according to these
configurations.