HUAWEI MU509-65 HSDPA LGA Module
Hardware Guide
Description of the Application Interfaces
Issue 01 (2016-04-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
28
3.4.3 RESIN_N Pin
The RESIN_N pin is used to reset the module's system. When the software stops
responding, the RESIN_N pin can be pulled down to reset the hardware.
Figure 3-8
Connections of the RESIN_N pin
Module
(DCE)
Micro
Control
(DTE)
b
c
e
RESIN_N
As the RESIN_N and POWER_ON_OFF pins are relatively sensitive, it is
recommended that you install a 10 nF capacitor near the RESIN_N and
POWER_ON_OFF pins of the interface for filtering. In addition, when you design a
circuit on the PCB of the interface board, it is recommended that the circuit length not
exceed 20 mm and that the circuit be kept at a distance of 2.54 mm (100 mil) at least
from the PCB edge. Furthermore, you need to wrap the area adjacent to the signal
wire with a ground wire. Otherwise, the module may be reset due to interference.
The MU509-65 module supports hardware reset function. If the software of the
MU509-65 module stops responding, you can reset the hardware through the
RESIN_N signal as shown in Figure 3-9 .When a low-level pulse is supplied through
the RESIN_N pin for 50 ms to 100 ms, the hardware will be reset. After the hardware
is reset, the software starts powering on the module and reports relevant information
according to the actual settings. For example, the AT command automatically reports
^SYSSTART.
Figure 3-9
Reset pulse timing
OPEN
GND
RESIN_N
50 ms-100 ms
The low-level pulse through the RESET pin cannot last for more than 2s. Otherwise, the
MU509-65 module will be powered off.
