Led_Wwan# Signal - Huawei MC509 Hardware Manual

HUAWEI MC509 CDMA Mini PCIe Module
Hardware Guide
Figure 3-7 Connections of the W_DISABLE# pin

3.4.5 LED_WWAN# Signal

MC509 provides an LED_WWAN# signal to indicate the RF status.
The pulse signal output through this pin controls the status LED on the user interface
board to display the network status. The LEDs are controlled by a current sink. The
high voltage is the voltage of VCC (with the typical value of 3.3 V). The planning drive
strength is 10 mA.
Figure 3-8 shows the recommended circuits of the LED_WWAN# pin. According to
LED feature, you can adjust the LED brightness by adjusting the resistance of resistor
R.
Figure 3-8 Driving circuit
Issue 03 (2014-12-26)
As the W_DISABLE# signal is relatively sensitive, it is recommended that you install a 10 nF

to 0.1 µF capacitor near the W_DISABLE# pin of the interface for filtering.
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 W_DISABLE# pin should be
below 50 mV.
The firmware function is in planning.
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