AN4146 datasheet(21/30 Pages) STMICROELECTRONICS

Part #	AN4146

Description	STSmartVoice demonstration board STEVAL-MKI126Vx

PDF	30 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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21 / 30 page

DocID023502 Rev 2

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AN4146

Software settings

The selection of the kit as a "Multi-microphone interface" also lets the user access the

dedicated panel given in the figure below.

Figure 17. Multi-microphone interface panel

The user can route the signal of the desired microphone on the output interfaces (I2S or HP

out) using the mapping drop-down menus on the right side of the panel. These menus act

on the pre-mixer of the respective channel. In the default configuration of the I2S output data

1 and 2 (SDO12), the pre-mixer of channel 1 takes 100% of PDMIN_1 (MIC1) and channel

2 takes 100% of PDMIN_2 (MIC2). The user can also directly edit the mixer values at will.

The post-mixer works in the same way, but takes a percentage of the outcome of the

processing block.

As an example, the figure below shows the layout of the pre- and post-mixer of channel1.

Figure 18. Pre- and post-mixer of channel 1

AN4146 Datasheet(PDF) 21 Page - STMicroelectronics