AN4146 datasheet(5/30 Pages) STMICROELECTRONICS

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AN4146

Demonstration board and accessories

The STSmartVoice board STEVAL-MKI126Vx requires a dedicated interface board,

STEVAL-CCA035V1 (APWLink) or STEVAL-MKI138V1 (ST audio hub), for programming

the device. Additional boards hosting the microphones are compatible with the board using

suitable connectors placed onboard. These boards are listed and shown in the following

sections and figures.

1.1

Interface

The STEVAL-CCA035V1 works as a programming board since it manages writing to the

I2C. The microphone processor is a digital device set using the I2C commands. In addition,

the STEVAL-CCA035V1 also serves as an interface board since the I2S provided by the

processor is routed on its connector (referred to as the APWLink connector). Finally, this

board also provides on the connector the 12.288 MHz clock used by the processor in case

the sampling frequency of the I2S is 192 kHz or 48 kHz.

Figure 2. STEVAL-CCA035V1 (APWLink)

The STEVAL-MKI138V1 performs the functions listed above plus supports audio streaming

via the USB cable. Basically the ST audio hub, using the STM32F107RC microcontroller, is

able to program the STA321MPL device via the I2C and decodes the I2S into a USB stream

in order for the PC to manage the sound captured by the microphones.

Figure 3. STEVAL-MKI138V1 (ST audio hub)

AN4146 Datasheet(PDF) 5 Page - STMicroelectronics