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@TJC
Last active Feb 15, 2021
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Teensy 3.0 (teensyduino) example program using Cortex-M4 DSP FFT function.
#define ARM_MATH_CM4
#include "arm_math.h"
#define TEST_LENGTH_SAMPLES 1024
#include "arm_fft_bin_data.h"
// static float32_t testOutput[TEST_LENGTH_SAMPLES/2];
// NOTE: q15t is int16_t in arm_math.h
/* ------------------------------------------------------------------
* Global variables for FFT Bin Example
* ------------------------------------------------------------------- */
uint32_t ifftFlag = 0;
uint32_t doBitReverse = 1;
/* Reference index at which max energy of bin ocuurs */
uint32_t refIndex = 213, testIndex = 0;
void setup() {
Serial.begin(19200);
pinMode(13, OUTPUT);
for (int i=0; i < 10; i++) {
Serial.println(" start program ");
delay(1000);
}
}
float my_cabs(float *arr) {
  return(sqrtf(arr[0]*arr[0] + arr[1]*arr[1]));
}
void loop() {
arm_cfft_radix4_instance_f32 fft_inst; /* CFFT Structure instance */
arm_cfft_radix4_init_f32(&fft_inst, 256, ifftFlag, doBitReverse);
Serial.println("step 1");
/* Process the data through the CFFT/CIFFT module */
arm_cfft_radix4_f32(&fft_inst, testInput_f32_10khz);
Serial.println("step 2");
for (int i=0; i < 32; i+=2) {
Serial.println(my_cabs(&testInput_f32_10khz[i]));
}
while (1) {
digitalWrite(13, HIGH);
Serial.println("done");
delay(5000);
digitalWrite(13, LOW);
delay(5000);
}
}
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