Led_Wwan# Signal - Huawei MU709 Series Hardware Manual

HUAWEI MU709 Series HSPA+ Mini PCIe Module
Hardware Guide
 As the RESIN_N signal is relatively sensitive, it is recommended that you install a
10 nF–0.1 µF capacitor near the RESIN_N pin 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 should not exceed 20 mm and that the circuit
should 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 maximum Forward Voltage Drop of the diode used in the module is 0.6 V. So
when the host wants to reset the module, the low-level-voltage in the RESIN_N pin
should be below 50 mV.
The MU709 module supports hardware reset function. If the software of the MU709
module stops responding, you can reset the hardware through the RESIN_N signal as
shown in Figure 3-6 . When a low-level pulse is supplied through the RESIN_N pin,
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 3-6 Reset pulse timing



3.4.4 LED_WWAN# Signal

MU709 series module provides an LED_WWAN# signal to indicate the work status.
This function is disabled by default, it is controlled by AT^LEDCTRL. For details about
the command, please refer to
Interface
Table 3-4 State of the LED_WWAN# pin
No. Operating Status
1
2
3
The RESIN_N pin must not be pulled down for more than 1s.
The RESIN_N pin is optional, which can not be connected.
HUAWEI MU709 Series HSPA+ Module AT Command
Specification.
No service or Restricted service Outputs: low (0.1s)-high (0.1s)-low
Register to the network
Dial-up successfully
Description of the Application Interfaces
LED_WWAN#
(0.1s)-high (1.7s)
2s cycle
Outputs: low (0.1s)-high (1.9s)
2s cycle
Outputs: low
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Copyright © Huawei Technologies Co., Ltd
Issue 04 (2015-06-25)
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