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EVDO PC Embedded Datasheet

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Product Datasheet
V001R006
Issue 2 (2009-01-20)
Confidencein Commercial
Page 28 of 60
3.2.5 W_DISABLE# Signal
The W_DISABLE# signal is provided to allow users to disable wireless
communications add-in cards. When the W_DISABLE# signal is asserted, all radios
should be disabled. When the W_DISABLE# signal is not asserted, the radio may
transmit if not disabled by other means such as software.
The W_DISABLE# signal is an active low signal with internal 100 kΩ pull-up resistor
that shall disable radio operation when being asserted (driven low) by the system.
Due to the potential of a software disable state, the combination of the software state
and W_DISABLE# assertion state must be determined before the normal operation is
resumed. Table 3-8 lists this requirement on the function of W_DISABLE# and the
software control setting. For example, the radio RF operation remains disabled
unless both the hardware and software are set to enable the RF features of the card.
Table 3-7 W_DISABLE_N signal
Pins
Name Description Direction to Module
20 W_DISABLE_N
Close wireless communications
Input
Table 3-8 Radio operational states
W_DISABLE#
SW Control Setting* Radio Operation
High Enabled Enabled
High Disabled
Low Enabled
Low Disabled
Disabled
* This control setting is implementation specific; this column represents the collective
intention of the host software to manage radio operation.
Notes:
We strongly recommend controlling this pin via hot-keys or a hardware switch. There are three
points as bellow:
1. If we don’t turn off radio manually, radio will be on when module is powered on.
2. End users need turn off radio at some situation like on an airplane.
3. According to Mini-PCIE specification, we must turn off radio through hardware or software.
Nearly all PC companies obey this specification.
3.2.6 LED_WWAN# Signal
The LED_WWAN signal of the EM660 can tolerate up to the voltage of 5 V and
absorb the current up to150 mA. According to the given circuit, in order to reduce the
current of the LED, a resistance of 1 kΩ must be placed in series with the LED.