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AnyTime AnyPlace Any Wireless Data Solution
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AD-2001-06-28 Ver 1.1
-17-
4.2 CODEC Interface
The CODEC Interface is configured by internal and external figures. If the internal CODEC
interface is used, additional glue logic is not necessary and the module
…
s very simple audio interface can
be used. Otherwise if the internal CODEC interface is not used, an external CODEC is necessary to
support the car-kit system. In this case, the module provides a PCM CODEC Interface.
4.2.1 Internal CODEC Interface
The module contains analog audio interface circuitry. The contained audio interface supports all of the
required conversation and amplification stages for the audio front end.
The audio interface includes the amplification stages for both the microphone and earphone. The
interface supports one single-ended microphone input and one single-ended earphone output.
Table 4-1 Analog Audio Pinouts
NAME
DESCRIPTION
CHARACTERISTIC
MIC2
MIC Input
Analog Input (Pin No. 58) *
EAR_DET1
EAR/MIC Set Detect
Logic Input (Pin No. 57) **
E
Earphone Output
Analog Output (Pin No. 60)
GND_A
Audio Ground
Audio Ground (Pin No. 59)
Note:
* MIC2, along with being a microphone input, checks to see if the user has pressed the headset key,
which allows the user to connect to or disconnect from a call. This pin is internally pulled high and is
therefore normally in the high state. To activate this input and connect to or disconnect from a call, the
user must set the MIC2 pin to a low state for 100ms to 200ms.
** EAR_DET1 checks to see if a headset has been connected to the ear-jack. When there is no headset
connected to the ear-jack, the audio path is disconnected. When a headset is connected to the ear-jack an
audio path is opened. To simulate a headset connected to the ear-jack, the user must apply a low signal to
the EAR_DET1 pin for as long as the user wants the audio path to be kept open.
