User's Manual

AH3-W Hardware Interface Overview
3.6 Analog Audio Interface
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AH3-W_HD_v01.000 Page 27 of 42 2012-05-29
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3.6 Analog Audio Interface
AH3-W has an analog audio interface with a balanced analog microphone input and a balanced
analog earpiece output. A supply voltage and an analog ground connection are provided at
dedicated pins.
AH3-W offers six audio modes which can be selected with the AT^SNFS command. The elec-
trical characteristics of the voiceband part vary with the audio mode. For example, sending and
receiving amplification, sidetone paths, noise suppression etc. depend on the selected mode
and can be altered with AT commands (except for mode 1).
When shipped from factory, all audio parameters of AH3-W are set to audio mode 1. This is the
default configuration optimised for the Votronic HH-SI-30.3/V1.1/0 handset and used for type
approving the Cinterion Wireless Modules reference configuration. Audio mode 1 has fix pa-
rameters which cannot be modified. To adjust the settings of the Votronic handset simply
change to another audio mode.
3.7 Pulse Code Modulation Interface (PCM)
AH3-W’s PCM interface can be used to connect audio devices capable of pulse code modula-
tion. The PCM functionality allows the use of a codec like the Freescale MC145483.
3.8 Analog-to-Digital Converter (ADC)
ADC is used for antenna diagnosis only.
3.9 GPIO Interface
The AH3-W has 10 GPIOs for external hardware devices. Each GPIO can be configured for
use as input or output. All settings are AT command controlled. The IO port driver has to be
open before using and configuring GPIOs. Before changing the configuration of a GPIO pin
(e.g. input to output) the pin has to be closed. If the GPIO pins are not configured or the pins/
driver were closed, the GPIO pins are high-Z with pull down resistor. If a GPIO is configured to
input, the pin has high-Z without pull resistor.