C5535 FFT Example?

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Posted by Joe McDaniel

on Nov 06 2011 10:47 AM

I would like a cookbook FFT filtering example for the C5535. I want to divide frequencies between 4k and 8k by 2 and between 8k and 16k by 4, for example.

There seem to be examples for, say, the C5505 but none for the C5535.

Best,

Joe

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Posted by Steve Tsang

on Feb 09 2012 09:49 AM

Genius12675 points

Have you checked the C5535/34/33/32 Technical Reference Manual in the product web site:

http://www.ti.com/lit/ug/spruh87b/spruh87b.pdf

Regards.

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Posted by Joe McDaniel

on Feb 09 2012 12:51 PM

Prodigy30 points

I did find some information there -- it led me to http://code.google.com/p/c5505-ezdsp/ where there are examples for the 5505 and 5515. In looking through other responses to the FFT questions, it appears that it is not a simple port for the 5515 code to the 5535. I did not find a 5535 example.

Best,

Joe

Posted by Mark Mckeown

on Feb 09 2012 19:22 PM

Genius10210 points

Hi Joe,

That FFT code should be moderately easy to port to the C5535 eZdsp.

Replace hwafft ROM addresses with those for C5535 in the .cmd file

hwafft_br       0x00fefe9c
hwafft_8pts       0x00fefeb0
hwafft_16pts   0x00feff9f
hwafft_32pts   0x00ff00f5
hwafft_64pts   0x00ff03fe
hwafft_128pts   0x00ff0593
hwafft_256pts   0x00ff07a4
hwafft_512pts   0x00ff09a2
hwafft_1024pts   0x00ff0c1c

Swap every instance of I2S0 with I2S2.

Make sure to configure EBSR PPMODE to MODE 1, 4, or 6 to bring out the I2S2 signals that are connected to the codec on the C5535 eZdsp (I2S0 was used on the C5505 & C5515 eZdsp to connec to to the codec).

I dont have the time now, but I will take a stab at it and post it on code.google.com or on the C5000 wiki some time soon.

Hope this helps,
Mark

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