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有没有ARN或者MSP432汇编语言的FFT历程 谢谢 十分感谢



有没有ARN或者MSP432汇编语言的FFT历程   谢谢  有的话把链接给我一下  十分感谢

  • 汇编的没有,ti官网提供了c语言的fft历程,楼主可以参考

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    //*****************************************************************************
    // QmathLib_signal_FFT_ex4: Qmath signal generator and complex FFT example.
    //
    // Generate an input signal based on an array of wave descriptors. Each wave
    // descriptor is composed of a frequency, amplitude and phase angle. The
    // input signal is constructed with a size of SAMPLES and assumes a sample
    // frequency defined by SAMPLE_FREQUENCY. The real component of the input
    // consists of the summation of all the waves at that time index and the
    // imaginary component is set to zero.
    //
    // The input array is passed into the complex FFT function which performs
    // the FFT in-place using radix-2. The result of the cFFT is stored in the
    // input array and is scaled by SAMPLES.
    //
    // The result is used to calculate the magnitude and phase angle at each
    // frequency bin up to SAMPLES/2 (Nyquist frequency). The magnitude and phase
    // angles are stored in data memory and should approximate the original
    // signal composition. Because the input signal did not have any imaginary
    // components the magnitude will be halved. The results can be printed with
    // the printf function if ALLOW_PRINTF is defined.
    //
    // B. Peterson
    // Texas Instruments Inc.
    // January 2015
    // Built with CCS version 6.1.0.00074 and IAR Embedded Workbench version
    // 7.30.4.8187.
    //*****************************************************************************
    #include "msp432.h"
    #include <stdio.h>
    #include <stdlib.h>
    #include <stdint.h>

    /* Select the global Q value and include the Qmath header file. */
    #define GLOBAL_Q 12
    #include "QmathLib.h"

    /* Specify the sample size and sample frequency. */
    #define SAMPLES 64 // <= 256, power of 2
    #define SAMPLE_FREQUENCY 8192 // <= 16384

    /* Access the real and imaginary parts of an index into a complex array. */
    #define RE(x) (((x)<<1)+0) // access real part of index
    #define IM(x) (((x)<<1)+1) // access imaginary part of index

    /*
    * Input and result buffers. These can be viewed in memory or printed by
    * defining ALLOW_PRINTF.
    */
    _q qInput[SAMPLES*2]; // Input buffer of complex values
    _q qMag[SAMPLES/2]; // Magnitude of each frequency result
    _q qPhase[SAMPLES/2]; // Phase of each frequency result

    /* Misc. definitions. */
    #define PI 3.1415926536

    /* Structure that describes a single wave to be used to construct the signal */
    typedef struct wave {
    int16_t frequency; // Frequency in Hz
    _q amplitude; // Amplitude of the signal
    _q phase; // Phase angle in radians
    } wave;

    /*
    * Specify wave structures that will be used to construct the input signal to
    * the complex FFT function.
    */
    const wave signals[] = {
    /* Frequency (Hz) Magnitude Phase angle (radians) */
    {128, _Q(0.5), _Q(PI/2)},
    {512, _Q(2.0), _Q(0)},
    {2048, _Q(1.333), _Q(-PI/2)}
    };

    /* Calculate the number of wave structures that have been provided. */
    #define NUM_WAVES (sizeof(signals)/sizeof(wave))

    //#define ALLOW_PRINTF // allow usage of printf to print results
    #ifdef ALLOW_PRINTF
    char cMagBuffer[10]; // Character buffer for printing magnitude
    char cPhaseBuffer[10]; // Character buffer for printing phase
    char cFrequencyBuffer[10]; // Character buffer for printing frequency
    #endif

    extern void cFFT(_q *input, int16_t n);

    int main(void)
    {
    int16_t i, j; // loop counters
    _q qWaveCurrentAngle[NUM_WAVES]; // input angles for each signal

    /* Disable WDT. */
    WDTCTL = WDTPW + WDTHOLD;

    /* Set the initial input angles. */
    for (i = 0; i < NUM_WAVES; i++) {
    qWaveCurrentAngle[i] = signals[i].phase;
    }

    /* Construct the input signal from the wave structures. */
    for (i = 0; i < SAMPLES; i++) {
    qInput[RE(i)] = 0;
    qInput[IM(i)] = 0;
    for (j = 0; j < NUM_WAVES; j++) {
    /*
    * input[RE] += cos(angle)*amplitude
    * angle += 2*pi*freq/sample_freq
    */
    qInput[RE(i)] += _Qmpy(_Qcos(qWaveCurrentAngle[j]), signals[j].amplitude);
    qWaveCurrentAngle[j] += _Qmpy(_Q(2*PI), _Qdiv(signals[j].frequency, SAMPLE_FREQUENCY));
    if (qWaveCurrentAngle[j] > _Q(PI)) {
    qWaveCurrentAngle[j] -= _Q(2*PI);
    }
    }
    }

    /*
    * Perform a complex FFT on the input samples. The result is calculated
    * in-place and will be stored in the input buffer.
    */
    cFFT(qInput, SAMPLES);

    /* Calculate the magnitude and phase angle of the results. */
    for (i = 0; i < SAMPLES/2; i++) {
    qMag[i] = _Qmag(qInput[RE(i)], qInput[IM(i)]);
    qPhase[i] = _Qatan2(qInput[IM(i)], qInput[RE(i)]);
    }

    /* Print the results. */
    #ifdef ALLOW_PRINTF
    for (i = 0; i < SAMPLES/2; i++) {
    _Qtoa(cMagBuffer, "%2.4f", qMag[i]);
    _Qtoa(cPhaseBuffer, "%2.4f", qPhase[i]);
    _Q1toa(cFrequencyBuffer, "%5.0f", _Q1mpyI16(_Q1(SAMPLE_FREQUENCY/SAMPLES), i));
    printf("%sHz: mag = %s, phase = %s radians\n",
    cFrequencyBuffer, cMagBuffer, cPhaseBuffer);
    }
    #endif

    return 0;
    }

    extern void cBitReverse(_q *input, int16_t n);

    /*
    * Perform in-place radix-2 DFT of the input signal with size n.
    *
    * This function has been written for any input size up to 256. This function
    * can be optimized by using lookup tables with precomputed twiddle factors for
    * a fixed sized FFT, using Q15 format for the twiddle factors and inlining the
    * multiplication steps with direct access to the MPY32 hardware peripheral.
    */
    void cFFT(_q *input, int16_t n)
    {
    int16_t s, s_2; // step
    uint16_t i, j; // loop counters
    _q qTAngle; // twiddle factor angle
    _q qTIncrement; // twiddle factor increment
    _q qTCos, qTSin; // complex components of twiddle factor
    _q qTempR, qTempI; // temp result complex pair

    /* Bit reverse the order of the inputs. */
    cBitReverse(input, n);

    /* Set step to 2 and initialize twiddle angle increment. */
    s = 2;
    s_2 = 1;
    qTIncrement = _Q(-2*PI);

    while (s <= n) {
    /* Reset twiddle angle and halve increment factor. */
    qTAngle = 0;
    qTIncrement = _Qdiv2(qTIncrement);

    for (i = 0; i < s_2; i++) {
    /* Calculate twiddle factor complex components. */
    qTCos = _Qcos(qTAngle);
    qTSin = _Qsin(qTAngle);
    qTAngle += qTIncrement;

    for (j = i; j < n; j += s) {
    /* Multiply complex pairs and scale each stage. */
    qTempR = _Qmpy(qTCos, input[RE(j+s_2)]) - _Qmpy(qTSin, input[IM(j+s_2)]);
    qTempI = _Qmpy(qTSin, input[RE(j+s_2)]) + _Qmpy(qTCos, input[IM(j+s_2)]);
    input[RE(j+s_2)] = _Qdiv2(input[RE(j)] - qTempR);
    input[IM(j+s_2)] = _Qdiv2(input[IM(j)] - qTempI);
    input[RE(j)] = _Qdiv2(input[RE(j)] + qTempR);
    input[IM(j)] = _Qdiv2(input[IM(j)] + qTempI);
    }
    }
    /* Multiply step by 2. */
    s_2 = s;
    s = _Qmpy2(s);
    }
    }

    /*
    * Perform an in-place bit reversal of the complex input array with size n.
    * Use a look up table to speed up the process. Valid for size of 256 and
    * smaller.
    */
    void cBitReverse(_q *input, int16_t n)
    {
    uint16_t i, j; // loop counters
    int16_t i16BitRev; // index bit reversal
    _q qTemp;

    extern const uint8_t ui8BitRevLUT[256];

    /* In-place bit-reversal. */
    for (i = 0; i < n; i++) {
    i16BitRev = ui8BitRevLUT[i];
    for (j = n; j < 256; j <<= 1) {
    i16BitRev >>= 1;
    }
    if (i < i16BitRev) {
    /* Swap inputs. */
    qTemp = input[RE(i)];
    input[RE(i)] = input[RE(i16BitRev)];
    input[RE(i16BitRev)] = qTemp;
    qTemp = input[IM(i)];
    input[IM(i)] = input[IM(i16BitRev)];
    input[IM(i16BitRev)] = qTemp;
    }
    }
    }

    /* 8-bit reversal lookup table. */
    const uint8_t ui8BitRevLUT[256] = {
    0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
    0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
    0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
    0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
    0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
    0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
    0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
    0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
    0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
    0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
    0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
    0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
    0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
    0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
    0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
    0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
    };

  • 关于MSP432的FFT,可以参考文档 http://www.ti.com/lit/an/slaa707/slaa707.pdf

    Signal Processing With MSP432 Microcontroller and CMSIS-DSP Library