Ura
Dependencies: CMSIS_DSP_401 mbed
main.cpp
- Committer:
- Sergeev
- Date:
- 2014-10-07
- Revision:
- 3:1f56b8f439a1
- Parent:
- 2:707eb5bc5dfc
- Child:
- 4:397e8f4699df
File content as of revision 3:1f56b8f439a1:
#include "mbed.h" #include <ctype.h> #include "arm_math.h" #include "arm_const_structs.h" void arm_cfft_f32( const arm_cfft_instance_f32 * S, float32_t * p1, uint8_t ifftFlag, uint8_t bitReverseFlag); Serial pc(USBTX, USBRX); AnalogIn left(A2); AnalogIn right(A3); int SAMPLE_RATE_HZ = 40000; // Sample rate of the audio in hertz. const int FFT_SIZE = 16; // Size of the FFT. const static arm_cfft_instance_f32 *S; //static arm_cfft_radix2_instance_f32 *S; Ticker samplingTimer; float samples[FFT_SIZE*2]; float magnitudes[FFT_SIZE]; int sampleCounter = 0; void samplingCallback() { // Read from the ADC and store the sample data samples[sampleCounter] = 1000*left.read(); // Complex FFT functions require a coefficient for the imaginary part of the input. // Since we only have real data, set this coefficient to zero. samples[sampleCounter+1] = 0.0; // Update sample buffer position and stop after the buffer is filled sampleCounter += 2; if (sampleCounter >= FFT_SIZE*2) { samplingTimer.detach(); } } void samplingBegin() { // Reset sample buffer position and start callback at necessary rate. sampleCounter = 0; samplingTimer.attach_us(&samplingCallback, (float)(1000000/SAMPLE_RATE_HZ)); } bool samplingIsDone() { return sampleCounter >= FFT_SIZE*2; } int main() { // Set up serial port. //pc.baud (38400); // Init arm_ccft_32 switch (FFT_SIZE) { case 16: S = & arm_cfft_sR_f32_len16; break; case 32: S = & arm_cfft_sR_f32_len32; break; case 64: S = & arm_cfft_sR_f32_len64; break; case 128: S = & arm_cfft_sR_f32_len128; break; case 256: S = & arm_cfft_sR_f32_len256; break; case 512: S = & arm_cfft_sR_f32_len512; break; case 1024: S = & arm_cfft_sR_f32_len1024; break; case 2048: S = & arm_cfft_sR_f32_len2048; break; case 4096: S = & arm_cfft_sR_f32_len4096; break; } float maxValue = 0.0f; unsigned int testIndex = 0; // Begin sampling audio samplingBegin(); while(1) { // Calculate FFT if a full sample is available. if (samplingIsDone()) { // Run FFT on sample data. //arm_cfft_radix2_f32(arm_cfft_radix2_instance_f32*S, samples); arm_cfft_f32(S, samples, 0, 1); samples[0] = samples[0]/1000; /* Initialize the CFFT/CIFFT module */ //arm_cfft_radix2_init_f32(S, 128, 0, 1); //arm_cfft_radix2_f32(S, samples); for(int i = 0;i < FFT_SIZE*2;++i) pc.printf(" Samples[%d]: %8.2f ",i,samples[i]); pc.printf("\r\n"); // Calculate magnitude of complex numbers output by the FFT. arm_cmplx_mag_f32(samples, magnitudes, FFT_SIZE); for(int i = 0;i < FFT_SIZE;++i) pc.printf(" Magnitude: %d = %8.2f ;", i, magnitudes[i]); pc.printf(" \r\n"); arm_max_f32(magnitudes, FFT_SIZE, &maxValue, &testIndex); pc.printf(" MAX value at magnitudes[%d] : %+8.2f\r\n", testIndex, maxValue); // Wait for user confirmation to restart audio sampling. //pc.getc(); wait(1); samplingBegin(); } } }