Complex 16-bit radix-4 FFT

UM0585

12/25

Doc ID 14988 Rev 2

1.

Comment all the FFT coefficients in the FFT function assembly file.

/* TableFFT_V7

;N=16

DC16 0x4000,0x0000, 0x4000,0x0000, 0x4000,0x0000

DC16 0xdd5d,0x3b21, 0x22a3,0x187e, 0x0000,0x2d41

DC16 0xa57e,0x2d41, 0x0000,0x2d41, 0xc000,0x4000

DC16 0xdd5d,0xe782, 0xdd5d,0x3b21, 0xa57e,0x2d41

; N=64

DC16 0x4000,0x0000, 0x4000,0x0000, 0x4000,0x0000

DC16 0x2aaa,0x1294, 0x396b,0x0646, 0x3249,0x0c7c

...

*/

2.

Then, in the main, include the table_fft.h file, which is a part of the DSP library.

3.

Finally, go to the FFT function assembly code, and inverse the comment in the following

lines:

ADRL

R0, TableFFT_V7

/* Coeff in Flash */

//LDR.W R0, =TableFFT

/* Coeff in RAM */