Go Down

Topic: Porting the ffft.h library to Arduino Due (Read 2550 times) previous topic - next topic


Can anyone please help in porting the ffft.h library to the Arduino Due. Compiling problems start with the avr\pgmspace.h include but seems to persist even when correctly linked.

Code: [Select]
#ifndef FFT_N
#define FFT_N 128/* Number of samples (64,128,256,512). Don't forget to clean! */
//#define INPUT_NOUSE
//#define INPUT_IQ

#ifndef FFFT_ASM /* for c modules */

typedef struct _tag_complex_t {
int16_t r;
int16_t i;
} complex_t;

#ifdef INPUT_IQ
void fft_input (const complex_t *, complex_t *);
extern "C" { void fft_input (const int16_t *, complex_t *); }
extern "C" {
void fft_execute (complex_t *);
void fft_output (complex_t *, uint16_t *);
int16_t fmuls_f (int16_t, int16_t);
#include <avr/pgmspace.h>
extern const prog_int16_t tbl_window[];

#else /* for asm module */

#define T0L r0
#define T0H r1
#define T2L r2
#define T2H r3
#define T4L r4
#define T4H r5
#define T6L r6
#define T6H r7
#define T8L r8
#define T8H r9
#define T10L r10
#define T10H r11
#define T12L r12
#define T12H r13
#define T14L r14
#define T14H r15
#define AL r16
#define AH r17
#define BL r18
#define BH r19
#define CL r20
#define CH r21
#define DL r22
#define DH r23
#define EL r24
#define EH r25
#define XL r26
#define XH r27
#define YL r28
#define YH r29
#define ZL r30
#define ZH r31

.macro ldiw dh,dl, abs
ldi \dl, lo8(\abs)
ldi \dh, hi8(\abs)

.macro subiw dh,dl, abs
subi \dl, lo8(\abs)
sbci \dh, hi8(\abs)

.macro addw dh,dl, sh,sl
add \dl, \sl
adc \dh, \sh

.macro addd d3,d2,d1,d0, s3,s2,s1,s0
add \d0, \s0
adc \d1, \s1
adc \d2, \s2
adc \d3, \s3

.macro subw dh,dl, sh,sl
sub \dl, \sl
sbc \dh, \sh

.macro subd d3,d2,d1,d0, s3,s2,s1,s0
sub \d0, \s0
sbc \d1, \s1
sbc \d2, \s2
sbc \d3, \s3

.macro lddw dh,dl, src
ldd \dl, \src
ldd \dh, \src+1

.macro ldw dh,dl, src
ld \dl, \src
ld \dh, \src

.macro stw dst, sh,sl
st \dst, \sl
st \dst, \sh

.macro clrw dh, dl
clr \dh
clr \dl

.macro lsrw dh, dl
lsr \dh
ror \dl

.macro asrw dh, dl
asr \dh
ror \dl

.macro lslw dh, dl
lsl \dl
rol \dh

.macro pushw dh, dl
push \dh
push \dl

.macro popw dh, dl
pop \dl
pop \dh

.macro lpmw dh,dl, src
lpm \dl, \src
lpm \dh, \src

.macro rjne lbl
breq 99f
rjmp \lbl

.macro FMULS16 d3,d2,d1,d0 ,s1h,s1l, s2h,s2l ;Fractional Multiply (19clk)
fmuls \s1h, \s2h
movw \d2, T0L
fmul \s1l, \s2l
movw \d0, T0L
adc \d2, EH ;EH: zero reg.
fmulsu \s1h, \s2l
sbc \d3, EH
add \d1, T0L
adc \d2, T0H
adc \d3, EH
fmulsu \s2h, \s1l
sbc \d3, EH
add \d1, T0L
adc \d2, T0H
adc \d3, EH

.macro SQRT32 ; 32bit square root (526..542clk)
clr T6L
clr T6H
clr T8L
clr T8H
ldi BL, 1
ldi BH, 0
clr CL
clr CH
ldi DH, 16
90: lsl T2L
rol T2H
rol T4L
rol T4H
rol T6L
rol T6H
rol T8L
rol T8H
lsl T2L
rol T2H
rol T4L
rol T4H
rol T6L
rol T6H
rol T8L
rol T8H
brpl 91f
add T6L, BL
adc T6H, BH
adc T8L, CL
adc T8H, CH
rjmp 92f
91: sub T6L, BL
sbc T6H, BH
sbc T8L, CL
sbc T8H, CH
92: lsl BL
rol BH
rol CL
andi BL, 0b11111000
ori BL, 0b00000101
sbrc T8H, 7
subi BL, 2
dec DH
brne 90b
lsr CL
ror BH
ror BL
lsr CL
ror BH
ror BL

#endif /* FFFT_ASM */

#endif /* FFT_N */


Hi there,

avr code does not run on the Due, as the SAM chip is entirely different - and is infact, not an AVR device.


Hi PetrusBotha,

The FFT library your using is as jtw11 states designed for AVR's, not ARM CPU's which run on the DUE board.

The 8 bit AVR's i.e. UNO, MEGA's etc don't have much balls regarding processing power. The library is coded to access the registers on the AVR directly too speed up the whole process.

The DUE is pretty powerful when is comes to microcontrollers and can handle a higher level FFT coding than the AVR's.

Refer to the attached link for an example which should work on the DUE and on anything else for that matter that runs C - even the ARV's although they may take significantly longer to process the data.

Most of the other libraries I have seen for the AVR's not only do the FFT, but also look after the signal processing i.e. windowing of the timewave before it gets put through the FFT. Windowing the data should be relatively easy though.

Let me know how you go!



Thank you Adam,

I will have a look at the code and let you know how it goes


Go Up