TLV320AIC3109EVM Software
16
SLAU738 – September 2017
Copyright © 2017, Texas Instruments Incorporated
TLV320AIC3109EVM-K
4.3
Audio Input/ADC Tab
The
Audio Input/ADC
tab allows control of the analog input mixer and the ADC. The controls are
displayed to look similar to an audio mixing console, as shown in
. Each analog input channel has
a vertical strip that corresponds to that channel. By default, all inputs are muted when the
TLV320AIC3109EVM is powered up.
Figure 9. Audio Input and ADC Tab
To route an analog input to the ADC:
1. Select the
Input Mode
button to correctly show if the input signal is single-ended (
SE
) or fully-
differential (
Diff
). Inputs that are single-ended should be made to the positive signal terminal.
2. Click on the button of the analog input channel that corresponds to the correct ADC. The caption of the
button should change to
Active
.
3. Adjust the
Level
control to the desired attenuation for the connected channel. This level adjustment
can be done independently for each connection.
The TLV320AIC3109-Q1 offers a programmable microphone bias that can either be powered down or set
to 2 V, 2.5 V, or the power supply voltage of the ADC (AVDD_ADC). Control of the microphone bias (mic
bias) voltage is accomplished by using the
Mic Bias
pull-down menu button above the last two channel
strips. To use the onboard microphone, J8 must be installed and nothing should be plugged into J9. In
order for the mic bias settings in the software to take effect, J7 should be set to connect positions 2 and 3
(INT), so that mic bias is controlled by the TLV320AIC3109-Q1.
In the upper right portion of this tab are controls for
Weak Common Mode Bias
. Enabling these controls
will result in unselected inputs to the ADC to be weakly biased to the ADC common mode voltage.
Below these controls are the controls for the ADC PGA, including the master volume controls for the ADC
inputs. The ADC channel can be powered up or down as needed using the
Powered Up
button. PGA
soft-stepping for the ADC channel is selected using the pull-down menu control. The large knob sets the
actual
ADC PGA Gain
and allows adjustment of the PGA gains from 0 dB to 59.5 dB, in 0.5-dB steps
(excluding Mute). At the extreme counterclockwise rotation, the channel is muted. Rotating the knob
clockwise increases the PGA gain, which is displayed in the box directly above the volume control.
