PDM audio software decoding library?

[ozvena]

Posted on January 18, 2012 at 17:17

1. Here is a description of the PDM audio software decoding library from the AN3998 PDF:

   The PDM audio software decoding library includes one header file pdm_filter.h and binary/object codes for the following platforms:

• â—�  libPDMFilter_IAR.a

• â—�  libPDMFilter_Keil.lib

• â—�  libPDMFilter_GCC.a

: for IAR compiler

: for ARM compiler: for GNU compiler

5.1

This Library is provided in the ''STM32F4-DISCOVERY board firmware package'' (V1.10and later) under the following path 'Utilities\STM32F4-Discovery'

Does it mean that other compilers cannot take advantage of the library? Or the library is a result of a compilation of the included .c and .h files provided in the same 

Utilities\STM32F4-Discovery folder?

Thank you!

[Tesla DeLorean]

Posted on January 18, 2012 at 18:09

It's built from pdm_filter.c, which they don't supply.

The libraries are in COFF/ELF format, so provided the ABI/linkage is consistent they should be usable with other linkers. Shouldn't take more than a couple of minutes to verify. The GCC version is built with Atollic, should be viable on Rowley or other GCC compilers. Need something different, then a call to your local ST FAE should suffice.

[mike_k_cook]

Posted on February 08, 2012 at 15:05

It's built from pdm_filter.c, which they don't supply.

I am trying to compile the audio recording example on CrossStudio and have hit this wall, is there any way I can get this file. Sorry I am new at this.

[Tesla DeLorean]

Posted on February 08, 2012 at 18:25

I don't have a current/working release of Rowley to hand, otherwise I'd go through the motions.

You should be able to drop

libPDMFilter_GCC.a

into your project, and along with the include file achieve linkage against the library without needing it's source, just like the projects for the other IDEs. If the link fails, the error might be instructive. If the link succeeds, the code will probably work, unless there is an internal mismatch between the compiler or ABI settings, compared to the libraries.

[mike_k_cook]

Posted on February 09, 2012 at 15:00

Thanks Clive, I can now get it to compile.

Of course it doesn't work but that is what I am beginning to expect from this board. Just trying the wave playback bit, no green LED, just the blue, toggling between flashing and steady as I flick the board. Not a dicky bird out of the earphone socket.