UM1900

Hardware description

DocID027905 Rev 3

11/19

In addition, J2 must be placed in position 1-2 for on-board microphone acquisition or 2-3

when using an external microphone while J3 must be left open. When acquiring on-board

microphones, close SB9 to acquire both of them.

4 microphone acquisition

In this case, the PDM line of the third and fourth microphone is also routed to the MCU.

Table 3: Solder bridge configuration for 4 microphone acquisition

SB

Status

SB7

Open

SB8

Open

SB9

Open

SB10

Open

SB11

Open

SB12

Close

SB13

Open

SB14

Open

SB15

Open

SB16

Close

SB17

Close

SB18

Open

SB19

Open

SB20

Open

SB21

Open

In addition, J2 and J3 must be placed in position 2-3 for external microphone acquisition.

3.4.2.2

Jumper settings for I²S-plus-SPI-based systems

1 microphone acquisition

The I²S peripheral is used directly to give the right clock to the microphone and thus

acquires the same microphone. For this use case, you need the following SB configuration.

Table 4: Solder bridge configuration for 1 microphone acquisition

SB

Status

SB7

Open

SB8

Open

SB9

Open

SB10

Open

SB11

Close

SB12

Open

SB13

Close

SB14

Close

SB15

Open