ST X-NUCLEO-CCA02M1, Руководство пользователя, Страница: 12 / 20

Hardware description UM1900
12/20 DocID027905 Rev 4
SB Status
SB15 Open
SB16 Open
SB17 Open
SB18 Open
SB19 Open
SB20 Open
SB21 Open
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. If using external
microphones, do not plug anything in
M2_EXT
header.
2 microphone acquisition
In this case, the I²S peripheral is used to generate twice the frequency needed by the
microphones. In this scenario, the clock is then halved by the timer and routed to the
microphones to give them the right clock. I²S therefore reads values from both edges of the
merged PDM lines.
Table 5: Solder bridge configuration for 2 microphone acquisition
SB Status
SB7 Close
SB8 Open
SB9 Open /Close
SB10 Open
SB11 Close
SB12 Open
SB13 Close
SB14 Open
SB15 Close
SB16 Open
SB17 Open
SB18 Open
SB19 Open
SB20 Open
SB21 Open
In addition, J2 must be placed in position 1-2 for on-board microphone acquisition or 2-3
when using external microphones, while J3 must be left open. When acquiring on-board
microphones, close SB9 to acquire both of them.