This is a simple application that outputs a single mic PDM.
This application is hardcoded for an MCLK of 24.576 MHz and PDM frequency of 3.072MHz.
To build:
$ cmake -B build -DCMAKE_TOOLCHAIN_FILE=xmos_cmake_toolchain/xs3a.cmake
$ cd build
$ make xk_voice_l71_pdm_recorder -j
To run:
$ xrun --xscope --xscope-file xscope.vcd xk_voice_l71_pdm_recorder.xe
Application will record PDM to file until application is closed.
Data out will be in xscope.vcd. Data format is in 32 bit format with the least significant byte being the oldest sample.
An example host python app in the host folder provides an example of how to convert the output into json for post processing. Note, the output vcd format represents the int data as binary, dropping leading 0's, IE, the 32 bit int value of decimal 1 will show up in the vcd output as b1, which must be interpretted as binary 00000000000000000000000000000001.