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[FAQ] CC2642R: CC13x2/CC26x2 器件上的 FFT

Part Number: CC2642R
Other Parts Discussed in Thread: CC1312R, CC2652R7, CC1352R, CC1352P, CC2652P, CC2652R

下面提供了利用 CC2642R 的 DSP 功能运行 FFT 的指南。

注意:该指南同样适用于所有具有 Cortex M4F 的 CC13xx 和 CC26xx 器件,其中包括 CC1312R、CC1352R、CC1352P、CC1352R7、CC2642R、CC2652R、CC2652P、CC2652R7 等

             a. 如果需要这里是我的 <SDK>\source\third_party\cmsis 文件夹cmsis.zip 的内容

  • 将它们存储在 <SDK>\source\third_party\cmsis\include 中
  • 打开 CCS,导入空示例
  • 添加库:“Project”>“Properties”>“Build”>“Arm Linker”>“File Search Path”。添加 third_party/cmsis/lib/math.lib

  • 在工程中新建一个名为 CMSIS 的文件夹,用于存储 CMSIS 库的头文件

  • 将 <SDK>\source\third_party\cmsis\include 中存储的文件复制到此新文件夹中
  • 将此文件夹添加到搜索路径:“Project”>“Properties”>“Build”>“Arm Compiler”>“Include Options”

我已使用 SDK 中提供的“empty”示例 (<SDK>\examples\rtos\<DEVICE>\drivers\empty) 对此进行了测试,并在其中添加了随库提供的示例。

以下是我的 empty.c 文件的修改内容:

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 * Copyright (c) 2015-2019, Texas Instruments Incorporated
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 *    notice, this list of conditions and the following disclaimer.
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 *    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,
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 */

/*
 *  ======== empty.c ========
 */

/* For usleep() */
#include <unistd.h>
#include <stdint.h>
#include <stddef.h>

/* Driver Header files */
#include <ti/drivers/GPIO.h>
// #include <ti/drivers/I2C.h>
// #include <ti/drivers/SPI.h>
// #include <ti/drivers/UART.h>
// #include <ti/drivers/Watchdog.h>

/* Driver configuration */
#include "ti_drivers_config.h"

#include "arm_math.h"
#include "arm_const_structs.h"

#define TEST_LENGTH_SAMPLES 4096

/* -------------------------------------------------------------------
* This is a fix for undefined __hardfp_sqrtf and __hardfp_sqrt symbols
* ------------------------------------------------------------------- */
int __hardfp_sqrt(int f){ return sqrt(f); }
float32_t __hardfp_sqrtf(float32_t f){ return sqrt(f); }

/* -------------------------------------------------------------------
* External Input and Output buffer Declarations for FFT Bin Example
* ------------------------------------------------------------------- */
extern float32_t testInput_f32_10khz[TEST_LENGTH_SAMPLES];
static float32_t testOutput[TEST_LENGTH_SAMPLES/2];

/* ------------------------------------------------------------------
* Global variables for FFT Bin Example
* ------------------------------------------------------------------- */
uint32_t fftSize = 2048;
uint32_t ifftFlag = 0;
uint32_t doBitReverse = 1;
arm_cfft_instance_f32 varInstCfftF32;
/* Reference index at which max energy of bin occurs */
uint32_t refIndex = 213, testIndex = 0;

/* ----------------------------------------------------------------------
* Max magnitude FFT Bin test
* ------------------------------------------------------------------- */
void MaxMagnitudeFFTBinTest(void)
{
  arm_status status;
  float32_t maxValue;
  status = ARM_MATH_SUCCESS;

  status=arm_cfft_init_f32(&varInstCfftF32,fftSize);

  /* Process the data through the CFFT/CIFFT module */
  GPIO_write(CONFIG_GPIO_LED_0, CONFIG_GPIO_LED_ON);
  GPIO_write(CONFIG_GPIO_LED_1, CONFIG_GPIO_LED_OFF);
  arm_cfft_f32(&varInstCfftF32, testInput_f32_10khz, ifftFlag, doBitReverse); // 2.587ms for 1024 points | 5.820ms for 2048 (280'411 clock cycles)
  GPIO_write(CONFIG_GPIO_LED_0, CONFIG_GPIO_LED_OFF);
  GPIO_write(CONFIG_GPIO_LED_1, CONFIG_GPIO_LED_ON);

  /* Process the data through the Complex Magnitude Module for
  calculating the magnitude at each bin */
  GPIO_write(CONFIG_GPIO_LED_0, CONFIG_GPIO_LED_ON);
  GPIO_write(CONFIG_GPIO_LED_1, CONFIG_GPIO_LED_OFF);
  arm_cmplx_mag_f32(testInput_f32_10khz, testOutput, fftSize); //22.020ms for 1024 points | 44.01 ms for 2048 points (2'128'459 clock cycles)
  GPIO_write(CONFIG_GPIO_LED_0, CONFIG_GPIO_LED_OFF);
  GPIO_write(CONFIG_GPIO_LED_1, CONFIG_GPIO_LED_ON);

  /* Calculates maxValue and returns corresponding BIN value */
  arm_max_f32(testOutput, fftSize, &maxValue, &testIndex);
  status = (testIndex != refIndex) ? ARM_MATH_TEST_FAILURE : ARM_MATH_SUCCESS;

  if (status != ARM_MATH_SUCCESS)
  {
      while (1); // something went wrong
  }
  else
  {
     // everything is working
  }
}

/*
 *  ======== mainThread ========
 */
void *mainThread(void *arg0)
{
    /* Call driver init functions */
    GPIO_init();
    // I2C_init();
    // SPI_init();
    // UART_init();
    // Watchdog_init();

    /* Configure the LED pin */
    GPIO_setConfig(CONFIG_GPIO_LED_0, GPIO_CFG_OUT_STD | GPIO_CFG_OUT_LOW);
    GPIO_setConfig(CONFIG_GPIO_LED_1, GPIO_CFG_OUT_STD | GPIO_CFG_OUT_LOW);

    /* Turn on user LED */

    MaxMagnitudeFFTBinTest(); // 24.77ms
 

    while (1) {
    }
}

您可能还需要查看此帖子、此主题和此应用手册以了解更多详细信息。