UM1871 datasheet(16/64 Pages) STMICROELECTRONICS

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Hardware layout and configuration

UM1871

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DocID027604 Rev 3

2.6

Audio

An audio codec WM8994ECS/R with 4 DACs and 2 ADCs inside, is connected to SAI

interface of STM32F446ZE, to support TDM feature on SAI port. This feature is able to

implement audio recording on digital microphone and analog microphone and audio

playback of different audio stream on headphones.

It communicates with STM32F446ZE via I2C4 bus which is shared with camera module,

RF-EEPROM and MFX (Multi Function eXpander).

The analog microphone on the headset is connected to ADC of WM8994ECS/R through

audio jack CN22. External speakers can be connected to WM8994ECS/R via audio jack

CN23.

Two digital microphones (MEMS microphone) MP34DT01TR are on STM32446E-EVAL

evaluation board. They can be connected either to audio codec or I2S port of STM32F446,

by setting jumpers as shown in Table 6: Audio related jumpers. The coupon connectors

CN26 and CN27 can be used to support MEMS microphone evaluation board STEVAL-

MKI129V1, after removing SB1 and SB133.

An optical connector CN2 is implemented on STM32446E-EVAL, to receive external audio

data which is compatible with SPDIF spec.

Table 6. Audio related jumpers

Jumper

Description

JP20

Data signal on digital microphone is connected to audio codec when JP20 is set as

shown on the right (default setting):

Data signal on digital microphone is connected to I2S port of STM32F446ZE when

JP20 is set as shown on the right:

JP19

Clock signal on digital microphone is connected to audio codec when JP19 is set as

shown on the right (default setting):

Clock signal on digital microphone is connected to Timer4 output (PD13) of

STM32F446ZE, used to divide by 2 the I2S3_CK, when JP19 is set, as shown on

the right (it is also needed to close SB23 and SB24 to use Timer 4 to manage

I2S3_CK):

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