TI中文支持网有没有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
灰小子：
汇编的没有，ti官网提供了c语言的fft历程，楼主可以参考
/* –COPYRIGHT–,BSD * Copyright (c) 2015, Texas Instruments Incorporated * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * * Neither the name of Texas Instruments Incorporated nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * –/COPYRIGHT–*///*****************************************************************************// 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};
Susan Yang：
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
