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FALCOM C2D-SI VERSION 1.07
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Page 19
Audio
2 V Microphone 2 bias voltage
0,5 mA Microphone 2 input current
> 50
Ω
(<1nF)
Speaker 1 impedance
> 50
Ω
(<1nF)
Speaker 2 impedance
Table 12:
Audio
4.2 Special functionality pins
Table 7 and table 8 show the pin-configuration of the AMP 177984-2.
In these tables CMOS means 2.8 V. You may use a 3 V or 3.3 V CMOS
level logic (never 5 V) on the 2.8 V I/O’s. However, it is required to add
serial resistance on all the lines you will use (typical value: from 4.7 to 10
K
Ω
).
There are a few pins needed for the operation of the module. The handling
of pins is described as follows.
Pin 30 (EN)
This signal is an input of the internal voltage regulator.
ƒ Pull to LOW to switch the voltage regulator off (for minimum current
consumption).
ƒ Pull to HIGH or leave the signal open if EN is not used.
Pin 27 (GPIO 1 Æ Flash_LED)
This signal can be used to show the current status of the module:
ƒ If GPIO 1 is LOW then the module is off.
ƒ If it is continuously HIGH then module is on, but not registered into a
network.
ƒ If GPIO 1 is flashing in a 2sec period then the module is on and
registered into a network.
ƒ If it flashes in a 1sec period then the module is on and a call is in
progress (incoming or outgoing).
GPIO 1 can be an input into a controller (here it needs to be driven by
an open collector circuit) or used together with a LED (see figure 3).