I am using STM32F407 Discovery Board for my audio project. There is a PDM mems microphone on this board. I want to get sound signal over I2S with DMA. For that ı am using SWV graph in İDE. I tried all ı found on the internet. ı have a few questions to make sure I am right. I think ı need to convert PDM data to PCM for meaningful graph. Is that right? I actually used the pdm2pcm library to do that. But all ı get is random numbers, it seems. Then, I try to observe the PDM signal with oscilloscope. The data signal was coming in two voltage levels. Is that normal for the PDM signal?
image below is taken at start of the run.
yellow signal is I2S CK(pb10), Cyan signal is data(pc3)
I started this project with an analog mic. It was success. The ADC codes not necessary for I2S;
