UM1900
Hardware
description
DocID027905 Rev 4
9/20
Figure 4: General acquisition strategy using I²S and SPI
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.
2.3
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, with
appropriate solder bridges. Clock routing can also be changed according to specific needs.
2.3.1
Solder bridge roles
The table below lists the solder bridge functions with respect to audio acquisition strategies.
Table 1: Solder bridge description
Function
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
Connects MIC34 PDM to MCU SPI
SB10
Connects MIC12 PDM to MCU I2S
SB11
