UM1900 Datasheet, PDF (9/19 Pages) STMicroelectronics – Getting started with the digital MEMS microphones expansion board based on MP34DT01-M for STM32 Nucleo

UM1900
Hardware description
Figure 4: General acquisition strategy using I²S and SPI
3.4
3.4.1
For single microphone acquisition, the correct microphone timer is generated directly by I²S
and one single microphone data line is read by the same peripheral.
Solder bridge configurations
Various board configurations are possible, depending on the use cases. MEMS
microphones can be plugged into ST morpho pins, and thus to MCU peripherals, using ad
hoc solder bridges. Clock routing can also be changed according to specific needs. This
section helps the user understand the role of each solder bridge and analyzes some of the
more common use cases.
Solder bridge roles
In the table below, the solder bridge functions are summarized with respect to the audio
acquisition strategies above.
Function
Table 1: Solder bridge description
Solder Bridge
Connects USB DM pin from connector to MCU
SB1
Connects USB DP pin from connector to MCU
SB2
Routes onboard oscillator output to OSC_IN MCU pin
SB6
Connect MEMS clock to MCU timer output channel
SB7
Routes I²S clock to SPI clock
SB8
Merges onboard microphone PDMs in order to be acquired with 1 interface
SB9
DocID027905 Rev 3
9/19