Luis Daniel Castillo / Mbed 2 deprecated KL25Z_FFT_Demo_tony

Simplified version of FFT code - drives on-board LED as a "Colour Organ".

Dependencies:   FastAnalogIn NVIC_set_all_priorities mbed-dsp mbed

Fork of KL25Z_FFT_Demo_tony by Tony Abbey

main.cpp@1:7421267b0777, 2016-11-15 (annotated)

Committer:
luisda130595
Date:
Tue Nov 15 22:16:24 2016 +0000
Revision:
1:7421267b0777
Parent:
0:b8c9dffbbe7e
Child:
2:177596541c8d
Pa' Ramiro

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tony1tf 0:b8c9dffbbe7e 1 // Audio Spectrum Display
tony1tf 0:b8c9dffbbe7e 2 // Copyright 2013 Tony DiCola (tony@tonydicola.com)
tony1tf 0:b8c9dffbbe7e 3 // Code ported from the guide at http://learn.adafruit.com/fft-fun-with-fourier-transforms?view=all
tony1tf 0:b8c9dffbbe7e 4 // mods by Tony Abbey to simplify code to drive tri-colour LED as a "colour organ"
tony1tf 0:b8c9dffbbe7e 5
tony1tf 0:b8c9dffbbe7e 6 #include "mbed.h"
tony1tf 0:b8c9dffbbe7e 7 #include "NVIC_set_all_priorities.h"
tony1tf 0:b8c9dffbbe7e 8 #include <ctype.h>
tony1tf 0:b8c9dffbbe7e 9 #include "arm_math.h"
tony1tf 0:b8c9dffbbe7e 10 #include "arm_const_structs.h"
tony1tf 0:b8c9dffbbe7e 11 #include "FastAnalogIn.h"
luisda130595 1:7421267b0777 12 #include <string>
tony1tf 0:b8c9dffbbe7e 13
luisda130595 1:7421267b0777 14 FastAnalogIn Audio(PTC2);
tony1tf 0:b8c9dffbbe7e 15 Serial pc(USBTX, USBRX);
tony1tf 0:b8c9dffbbe7e 16
tony1tf 0:b8c9dffbbe7e 17
tony1tf 0:b8c9dffbbe7e 18 //#define RGBW_ext // Disable this line when you want to use the KL25Z on-board RGB LED.
tony1tf 0:b8c9dffbbe7e 19
tony1tf 0:b8c9dffbbe7e 20
tony1tf 0:b8c9dffbbe7e 21 #ifndef RGBW_ext
tony1tf 0:b8c9dffbbe7e 22 // RGB direct output to PWM channels - on-board RGB LED
tony1tf 0:b8c9dffbbe7e 23 PwmOut gled(LED_GREEN);
tony1tf 0:b8c9dffbbe7e 24 PwmOut rled(LED_RED);
tony1tf 0:b8c9dffbbe7e 25 PwmOut bled(LED_BLUE);
tony1tf 0:b8c9dffbbe7e 26 #else
tony1tf 0:b8c9dffbbe7e 27 // HSI to RGBW conversion with direct output to external PWM channels - RGBW LED
tony1tf 0:b8c9dffbbe7e 28 // hsi2rgbw_pwm led(PTD4, PTA12, PTA4, PTA5); //Red, Green, Blue, White
tony1tf 0:b8c9dffbbe7e 29 #endif
tony1tf 0:b8c9dffbbe7e 30
tony1tf 0:b8c9dffbbe7e 31 // Dummy ISR for disabling NMI on PTA4 - !! DO NOT REMOVE THIS !!
tony1tf 0:b8c9dffbbe7e 32 // More info at https://mbed.org/questions/1387/How-can-I-access-the-FTFA_FOPT-register-/
tony1tf 0:b8c9dffbbe7e 33 extern "C" void NMI_Handler() {
tony1tf 0:b8c9dffbbe7e 34 DigitalIn test(PTA4);
tony1tf 0:b8c9dffbbe7e 35 }
tony1tf 0:b8c9dffbbe7e 36
tony1tf 0:b8c9dffbbe7e 37
tony1tf 0:b8c9dffbbe7e 38 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 39 // CONFIGURATION
tony1tf 0:b8c9dffbbe7e 40 // These values can be changed to alter the behavior of the spectrum display.
tony1tf 0:b8c9dffbbe7e 41 // KL25Z limitations
tony1tf 0:b8c9dffbbe7e 42 // -----------------
tony1tf 0:b8c9dffbbe7e 43 // - When used with the Spectrogram python script :
tony1tf 0:b8c9dffbbe7e 44 // There is a substantial time lag between the music and the screen output.
tony1tf 0:b8c9dffbbe7e 45 // Max allowed SAMPLE_RATE_HZ is 40000
tony1tf 0:b8c9dffbbe7e 46 // Max allowed FFT_SIZE is 64
tony1tf 0:b8c9dffbbe7e 47 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 48 // A value >= 1000 and <= 1000 + PIXEL_COUNT fixes the output to a single frequency
tony1tf 0:b8c9dffbbe7e 49 // window = a single color.
luisda130595 1:7421267b0777 50 int SAMPLE_RATE_HZ = 1000; // Sample rate of the audio in hertz.
luisda130595 1:7421267b0777 51
tony1tf 0:b8c9dffbbe7e 52 // Useful for turning the LED display on and off with commands from the serial port.
luisda130595 1:7421267b0777 53 const int FFT_SIZE = 256; // Size of the FFT.
tony1tf 0:b8c9dffbbe7e 54
tony1tf 0:b8c9dffbbe7e 55 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 56 // INTERNAL STATE
tony1tf 0:b8c9dffbbe7e 57 // These shouldn't be modified unless you know what you're doing.
tony1tf 0:b8c9dffbbe7e 58 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 59 const static arm_cfft_instance_f32 *S;
tony1tf 0:b8c9dffbbe7e 60 Ticker samplingTimer;
tony1tf 0:b8c9dffbbe7e 61 float samples[FFT_SIZE*2];
tony1tf 0:b8c9dffbbe7e 62 float magnitudes[FFT_SIZE];
tony1tf 0:b8c9dffbbe7e 63 int sampleCounter = 0;
tony1tf 0:b8c9dffbbe7e 64
luisda130595 1:7421267b0777 65 int arrayPosition;
luisda130595 1:7421267b0777 66 int maxFrequencyValue;
tony1tf 0:b8c9dffbbe7e 67
luisda130595 1:7421267b0777 68 int FFTFrequency;
tony1tf 0:b8c9dffbbe7e 69
tony1tf 0:b8c9dffbbe7e 70 // Convert a frequency to the appropriate FFT bin it will fall within.
tony1tf 0:b8c9dffbbe7e 71 int frequencyToBin(float frequency)
tony1tf 0:b8c9dffbbe7e 72 {
tony1tf 0:b8c9dffbbe7e 73 float binFrequency = float(SAMPLE_RATE_HZ) / float(FFT_SIZE);
tony1tf 0:b8c9dffbbe7e 74 return int(frequency / binFrequency);
tony1tf 0:b8c9dffbbe7e 75 }
tony1tf 0:b8c9dffbbe7e 76
tony1tf 0:b8c9dffbbe7e 77
tony1tf 0:b8c9dffbbe7e 78
tony1tf 0:b8c9dffbbe7e 79 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 80 // SAMPLING FUNCTIONS
tony1tf 0:b8c9dffbbe7e 81 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 82
tony1tf 0:b8c9dffbbe7e 83 void samplingCallback()
tony1tf 0:b8c9dffbbe7e 84 {
tony1tf 0:b8c9dffbbe7e 85 // Read from the ADC and store the sample data
tony1tf 0:b8c9dffbbe7e 86 samples[sampleCounter] = (1023 * Audio) - 511.0f;
tony1tf 0:b8c9dffbbe7e 87 // Complex FFT functions require a coefficient for the imaginary part of the input.
tony1tf 0:b8c9dffbbe7e 88 // Since we only have real data, set this coefficient to zero.
tony1tf 0:b8c9dffbbe7e 89 samples[sampleCounter+1] = 0.0;
tony1tf 0:b8c9dffbbe7e 90 // Update sample buffer position and stop after the buffer is filled
tony1tf 0:b8c9dffbbe7e 91 sampleCounter += 2;
tony1tf 0:b8c9dffbbe7e 92 if (sampleCounter >= FFT_SIZE*2) {
tony1tf 0:b8c9dffbbe7e 93 samplingTimer.detach();
tony1tf 0:b8c9dffbbe7e 94 }
tony1tf 0:b8c9dffbbe7e 95 }
tony1tf 0:b8c9dffbbe7e 96
tony1tf 0:b8c9dffbbe7e 97 void samplingBegin()
tony1tf 0:b8c9dffbbe7e 98 {
tony1tf 0:b8c9dffbbe7e 99 // Reset sample buffer position and start callback at necessary rate.
tony1tf 0:b8c9dffbbe7e 100 sampleCounter = 0;
tony1tf 0:b8c9dffbbe7e 101 samplingTimer.attach_us(&samplingCallback, 1000000/SAMPLE_RATE_HZ);
tony1tf 0:b8c9dffbbe7e 102 }
tony1tf 0:b8c9dffbbe7e 103
tony1tf 0:b8c9dffbbe7e 104 bool samplingIsDone()
tony1tf 0:b8c9dffbbe7e 105 {
tony1tf 0:b8c9dffbbe7e 106 return sampleCounter >= FFT_SIZE*2;
tony1tf 0:b8c9dffbbe7e 107 }
tony1tf 0:b8c9dffbbe7e 108
tony1tf 0:b8c9dffbbe7e 109 ////////////////////////////////////////////////////////////////////////////////
luisda130595 1:7421267b0777 110 // FREQUENCY
tony1tf 0:b8c9dffbbe7e 111 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 112
luisda130595 1:7421267b0777 113
luisda130595 1:7421267b0777 114 void set_ArrayPosition()
tony1tf 0:b8c9dffbbe7e 115 {
luisda130595 1:7421267b0777 116 float maxValue = 0.0;
tony1tf 0:b8c9dffbbe7e 117
luisda130595 1:7421267b0777 118 for(int counter=0; counter < FFT_SIZE; counter++)
luisda130595 1:7421267b0777 119 {
luisda130595 1:7421267b0777 120 if(magnitudes[counter] > maxValue){
luisda130595 1:7421267b0777 121 maxValue = magnitudes[counter];
luisda130595 1:7421267b0777 122 arrayPosition = counter+1;
tony1tf 0:b8c9dffbbe7e 123 }
tony1tf 0:b8c9dffbbe7e 124 }
tony1tf 0:b8c9dffbbe7e 125 }
tony1tf 0:b8c9dffbbe7e 126
luisda130595 1:7421267b0777 127 int get_FFTFrequency()
luisda130595 1:7421267b0777 128 {
luisda130595 1:7421267b0777 129 maxFrequencyValue = SAMPLE_RATE_HZ/2;
luisda130595 1:7421267b0777 130
luisda130595 1:7421267b0777 131 set_ArrayPosition();
luisda130595 1:7421267b0777 132
luisda130595 1:7421267b0777 133 return (maxFrequencyValue*arrayPosition)/FFT_SIZE;
luisda130595 1:7421267b0777 134
luisda130595 1:7421267b0777 135 }
tony1tf 0:b8c9dffbbe7e 136 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 137 // MAIN FUNCTION
tony1tf 0:b8c9dffbbe7e 138 ////////////////////////////////////////////////////////////////////////////////
tony1tf 0:b8c9dffbbe7e 139
tony1tf 0:b8c9dffbbe7e 140 int main()
tony1tf 0:b8c9dffbbe7e 141 {
tony1tf 0:b8c9dffbbe7e 142 NVIC_set_all_irq_priorities(1);
tony1tf 0:b8c9dffbbe7e 143 NVIC_SetPriority(UART0_IRQn, 0);
tony1tf 0:b8c9dffbbe7e 144
tony1tf 0:b8c9dffbbe7e 145 // Begin sampling audio
tony1tf 0:b8c9dffbbe7e 146 samplingBegin();
tony1tf 0:b8c9dffbbe7e 147
tony1tf 0:b8c9dffbbe7e 148 // Init arm_ccft_32
tony1tf 0:b8c9dffbbe7e 149 switch (FFT_SIZE)
tony1tf 0:b8c9dffbbe7e 150 {
tony1tf 0:b8c9dffbbe7e 151 case 16:
tony1tf 0:b8c9dffbbe7e 152 S = & arm_cfft_sR_f32_len16;
tony1tf 0:b8c9dffbbe7e 153 break;
tony1tf 0:b8c9dffbbe7e 154 case 32:
tony1tf 0:b8c9dffbbe7e 155 S = & arm_cfft_sR_f32_len32;
tony1tf 0:b8c9dffbbe7e 156 break;
tony1tf 0:b8c9dffbbe7e 157 case 64:
tony1tf 0:b8c9dffbbe7e 158 S = & arm_cfft_sR_f32_len64;
tony1tf 0:b8c9dffbbe7e 159 break;
tony1tf 0:b8c9dffbbe7e 160 case 128:
tony1tf 0:b8c9dffbbe7e 161 S = & arm_cfft_sR_f32_len128;
tony1tf 0:b8c9dffbbe7e 162 break;
tony1tf 0:b8c9dffbbe7e 163 case 256:
tony1tf 0:b8c9dffbbe7e 164 S = & arm_cfft_sR_f32_len256;
tony1tf 0:b8c9dffbbe7e 165 break;
tony1tf 0:b8c9dffbbe7e 166 case 512:
tony1tf 0:b8c9dffbbe7e 167 S = & arm_cfft_sR_f32_len512;
tony1tf 0:b8c9dffbbe7e 168 break;
tony1tf 0:b8c9dffbbe7e 169 case 1024:
tony1tf 0:b8c9dffbbe7e 170 S = & arm_cfft_sR_f32_len1024;
tony1tf 0:b8c9dffbbe7e 171 break;
tony1tf 0:b8c9dffbbe7e 172 case 2048:
tony1tf 0:b8c9dffbbe7e 173 S = & arm_cfft_sR_f32_len2048;
tony1tf 0:b8c9dffbbe7e 174 break;
tony1tf 0:b8c9dffbbe7e 175 case 4096:
tony1tf 0:b8c9dffbbe7e 176 S = & arm_cfft_sR_f32_len4096;
tony1tf 0:b8c9dffbbe7e 177 break;
tony1tf 0:b8c9dffbbe7e 178 }
tony1tf 0:b8c9dffbbe7e 179
luisda130595 1:7421267b0777 180 while(true) {
tony1tf 0:b8c9dffbbe7e 181 // Calculate FFT if a full sample is available.
tony1tf 0:b8c9dffbbe7e 182 if (samplingIsDone()) {
tony1tf 0:b8c9dffbbe7e 183 // Run FFT on sample data.
tony1tf 0:b8c9dffbbe7e 184 arm_cfft_f32(S, samples, 0, 1);
tony1tf 0:b8c9dffbbe7e 185 // Calculate magnitude of complex numbers output by the FFT.
tony1tf 0:b8c9dffbbe7e 186 arm_cmplx_mag_f32(samples, magnitudes, FFT_SIZE);
luisda130595 1:7421267b0777 187 //Obtaining the value of the frequency
luisda130595 1:7421267b0777 188 FFTFrequency = get_FFTFrequency();
luisda130595 1:7421267b0777 189
luisda130595 1:7421267b0777 190 for(int i=0;
luisda130595 1:7421267b0777 191 pc.printf("Frequency is: ", FFTFrequency);
luisda130595 1:7421267b0777 192 pc.printf("\r\n [");
luisda130595 1:7421267b0777 193
tony1tf 0:b8c9dffbbe7e 194 // Restart audio sampling.
tony1tf 0:b8c9dffbbe7e 195 samplingBegin();
luisda130595 1:7421267b0777 196 }
tony1tf 0:b8c9dffbbe7e 197 }
luisda130595 1:7421267b0777 198
tony1tf 0:b8c9dffbbe7e 199 }