FFT with arm math / CMSIS DSP

[bko]

Hi @jan1

You need to go back re-read this thread:

Integrate CMSIS library into Firmware

Hi I am trying to integrate the CMSIS DSP liibrary into my application for photon. I am using the pre-built library shipped with the CMSIS archive : libarm_cortexM3l_math.a. I have added a linker flag to use this library in the photon user-part makefile (modules/photon/user-part/makefile, in the firmware)in the archive. +LDFLAGS += -L/path/to/my/lib/libarm_cortexM3l_math.a However when I make a call to a routine the build breaks with an undefined reference error: undefined reference to `arm…

This is a fairly advanced maneuver and involves using a local gcc compile (probably a given already) and changing some makefiles plus using what is called a monolithic or one-part build. The poster at the end of that thread got it working.

With monolithic build you give up the possibility of over-the-air flashing.

This seems like a lot of work to me to get the highly optimized ARM FFT library. Have you considered just using a plain C FFT function instead? There are lots of examples on the web.