Looking for FIR in C for 21061 EZ-Kit

Hi there,

Is this true, that's impossible to create properly working FIR using 
VisualDSP 3.0 for 21061 EZ-Kit ?

I tried to run simple FIR (using different codes, samplerates and 
coefficients), and only what I got is noise :(

Is there anybody, who have a working FIR filter project written in C for 
21061 EZ-Lite ?

Thanks,
Jarek

On 12 Apr., 22:13, Jarek <a...@me.4> wrote:
> Hi there,
>
> Is this true, that's impossible to create properly working FIR using
> VisualDSP 3.0 for 21061 EZ-Kit ?
>
> I tried to run simple FIR (using different codes, samplerates and
> coefficients), and only what I got is noise :(
>
> Is there anybody, who have a working FIR filter project written in C for
> 21061 EZ-Lite ?

There is example C code for an FIR in this sub-directory:

...\21k\Examples\C_Examples\C-FIR

"..." is the installation directory of VisualDSP. This example uses
fixed-point processing. Be careful with the format of the input to the
FIR routine, it must also be fixed-point (Q32).

However, you cannot use the hardware circular buffers in C, and the
example code actually goes and manually shifts each delay, which is
hopelessly inefficient. If you insist on using C (in assembler, the
whole exercise can be implemented in 4 instructions), you should
consider one of the tricks mentioned under "Part 4: FIR
Implementation" in the DspGuru FIR faq:

http://www.dspguru.com/info/faqs/firfaq.htm

Regards,
Andor