PDM MEMS Microphone Not Working Properly When Attached to PB14

[wenjing]

i am working on an acoustic project and starting with ST products below:

nucleo-F413zh:https://www.st.com/en/evaluation-tools/nucleo-f413zh.html

X-NUCLEO-CCA02M1:https://www.st.com/en/ecosystems/x-nucleo-cca02m1.html

STEVAL-MIC001V1:https://www.st.com/en/evaluation-tools/steval-mic001v1.html

but i got different PDM waveform output

for mic1 on the left, the output is below,C2 for pdm data,C3 for clock

 

 

however,for mic2 on the right, the output is below,C2 for pdm data,C3 for clock

 

 

 I have switched two mics, it turns out that the moment DATA pin of mems mic attached to PB14 of stm32f413zh, the waveform would turn from rectangle wave to the weird wave,

according to my configuration in cubemx,i have already set PB14 as a input channel of DFSDM1:

i have upload my cubeide project.

Could someone please help me with that:

1.Is the Mems microphone working properly? Is the rectangle wave a correct PDM output?

2.What could possibly cause this problem? Why PB14 would make the waveform transfer from rectangle wave to a weird wave? How can i deal with it?

[wenjing]

BTW, i also switched between two Nucleo-F413zh ,and this problem occurs on both

 

[Andreas Bolsch · Accepted solution]

According to UM1974, red LED is connected to PB14 by default. Did you remove SB118?

[wenjing]

thank you for your reply! Your advice do help me a lot!

i did forgot to remove the led on the nucleo