KL25Z_FFT_Demo - Audio Spectrum analyser - FFT using mbed-dsp - dr…

Users » frankvnk » Code » KL25Z_FFT_Demo

Frank Vannieuwkerke / Mbed 2 deprecated KL25Z_FFT_Demo

Audio Spectrum analyser - FFT using mbed-dsp - driving RGB(W) LED or PC python script.

Dependencies: HSI2RGBW_PWM NVIC_set_all_priorities mbed-dsp mbed FastAnalogIn

Spectrum Analyzer

Code ported from Tony DiCola at AdaFruit FFT: Fun with Fourier Transforms.
Modifications were made to allow the use of the KL25Z on-board RGB LED or an external RGBW power LED.
See items marked with ^* in the next sections.

Main features

Uses mbed-dsp library.
Uses FastAnalogIn to allow a sample rate of 40kHz.
Display the audio spectrum on a single RGB(W) LED^*.
Display the audio spectrum on your computer using an audio spectrogram tool (python script).
Change parameters using a terminal connection : Sample rate, min/max db, slowdown^*.

Information

Detailed information and download of the python scripts is available here.

KL25Z wiring

Audio inputs
The software samples a single audio channel at 40kHz and applies a Fourier transform to return the frequency spectrum.
Analog input : PTC2.
A DC offset, and possibly some amplification or attenuation, is needed before the signal is fed into the analog inputs.
The opamp choice is not critical, just make sure it supports single supply operation.
Schematic
Currently, only one channel is used when the KL25Z is sampling at 40kHz.
/media/uploads/frankvnk/opamp_input_stage-tlc2264.png

External PWM outputs

Pin	Color
PTD4	Red
PTA12	Green
PTA4	Blue
PTA5	White

If you want to use a RGB LED, remove the last pin declaration (PTA5).
The conversion routine automatically switches from HSI/RGBW to HSI/RGB.
To use the external RGBW LED, enable following line in the code:

#define RGBW_ext // Disable this line when you want to use the KL25Z on-board RGB LED.

Commands

Parameters can be altered through the serial port Using a terminal program (eg : TeraTerm).
Communication settings : 38400 baud + local echo.
Each command needs to be terminated with a semicolon.
Use GET <command>; to read a parameter.
Use SET <command> <value>; to set a parameter.

Command	Description
GET MAGNITUDES;	Reads back the FFT magnitudes. Number of magnitudes = PIXEL_COUNT.
GET SAMPLES;	Reads back the current samples. Number of samples = PIXEL_COUNT.
GET FFT_SIZE;	The size of the FFT.
GET SAMPLE_RATE_HZ;	Audio sample rate (Hz).
SET SAMPLE_RATE_HZ <value>;	Change the audio sample rate (see also 'Limitations' below).
GET LEDS_ENABLED;	LEDs enabled status.
SET LEDS_ENABLED <value>;	Control if the LED's should display the spectrum or not. 1 is true, 0 is false.
GET SPECTRUM_MIN_DB;	Audio intensity (in decibels) that maps to low LED brightness.
SET SPECTRUM_MIN_DB <value>;	Change low sensitivity (0...100dB).
GET SPECTRUM_MAX_DB;	Audio intensity (in decibels) that maps to high LED brightness.
SET SPECTRUM_MAX_DB <value>;	Change high sensitivity (0...100dB).
GET SLOWDOWN;	LED visualisation delay.
SET SLOWDOWN <value>;	^* Useful to visualize the spectrum using a single RGB(W) LED. Without this command, the color values are shown too fast for the human eye. This allows you to slow down the visualization without interfering in the FFT conversion. Each frequency window is shown a little longer. The number of frequency windows depends on the value of the `PIXEL_COUNT` variable. [0...999] The larger the value, the longer each frequency window is shown - a good value is 4 when PIXEL_COUNT = 32 (choose a higher SLOWDOWN value when PIXEL_COUNT is lowered). [1000...1000 + PIXEL_COUNT] Selecting a value within this range allows us to lock to a specific frequency window.

NOTE : PIXEL_COUNT is declared at compile time and determines the number of frequency windows (aka LED colors).

Limitations

The original code was written for a cortex-M4 processor.
For a cortex-M0 processor, following limitations apply:

SAMPLE_RATE_HZ	FFT_SIZE
1...40000	max 64

Demo Videos

Parameter settings

SLOWDOWN	16 (initial value - changed to 1000+ during the video to demonstrate the lock option).
SAMPLE_RATE_HZ	40000
SPECTRUM_MIN_DB	40.0
SPECTRUM_MAX_DB	80.0
FFT_SIZE	64
PIXEL_COUNT	32

Using the on-board RGB LED
SLOWDOWN is set to different values (normal mode and locked mode).

Using an external 10W RGBW LED
SLOWDOWN is set to different values (normal mode and locked mode).

Spectrogram on Computer screen (serial input from KL25Z board

main.cpp@2:035d551759a5, 2014-03-08 (annotated)

Committer:: frankvnk
Date:: Sat Mar 08 19:30:20 2014 +0000
Revision:: 2:035d551759a5
Parent:: 1:736b34e0f484

Replaced deprecated FFT calls with new ones.

Who changed what in which revision?

User	Revision	Line number	New contents of line
frankvnk	0:0c037aff5039	1	// Audio Spectrum Display
frankvnk	0:0c037aff5039	2	// Copyright 2013 Tony DiCola (tony@tonydicola.com)
frankvnk	0:0c037aff5039	3	// Code ported from the guide at http://learn.adafruit.com/fft-fun-with-fourier-transforms?view=all
frankvnk	0:0c037aff5039	4
frankvnk	0:0c037aff5039	5	#include "mbed.h"
frankvnk	0:0c037aff5039	6	#include "NVIC_set_all_priorities.h"
frankvnk	0:0c037aff5039	7	#include <ctype.h>
frankvnk	0:0c037aff5039	8	#include "arm_math.h"
frankvnk	2:035d551759a5	9	#include "arm_const_structs.h"
frankvnk	0:0c037aff5039	10	#include "hsi2rgbw_pwm.h"
frankvnk	1:736b34e0f484	11	#include "FastAnalogIn.h"
frankvnk	0:0c037aff5039	12
frankvnk	0:0c037aff5039	13	Serial pc(USBTX, USBRX);
frankvnk	0:0c037aff5039	14
frankvnk	1:736b34e0f484	15	FastAnalogIn Audio(PTC2);
frankvnk	0:0c037aff5039	16
frankvnk	0:0c037aff5039	17	//#define RGBW_ext // Disable this line when you want to use the KL25Z on-board RGB LED.
frankvnk	0:0c037aff5039	18
frankvnk	0:0c037aff5039	19	#ifndef RGBW_ext
frankvnk	0:0c037aff5039	20	// HSI to RGB conversion with direct output to PWM channels - on-board RGB LED
frankvnk	0:0c037aff5039	21	hsi2rgbw_pwm led(LED_RED, LED_GREEN, LED_BLUE);
frankvnk	0:0c037aff5039	22	#else
frankvnk	0:0c037aff5039	23	// HSI to RGBW conversion with direct output to external PWM channels - RGBW LED
frankvnk	0:0c037aff5039	24	hsi2rgbw_pwm led(PTD4, PTA12, PTA4, PTA5); //Red, Green, Blue, White
frankvnk	0:0c037aff5039	25	#endif
frankvnk	0:0c037aff5039	26
frankvnk	0:0c037aff5039	27	// Dummy ISR for disabling NMI on PTA4 - !! DO NOT REMOVE THIS !!
frankvnk	0:0c037aff5039	28	// More info at https://mbed.org/questions/1387/How-can-I-access-the-FTFA_FOPT-register-/
frankvnk	0:0c037aff5039	29	extern "C" void NMI_Handler() {
frankvnk	0:0c037aff5039	30	DigitalIn test(PTA4);
frankvnk	0:0c037aff5039	31	}
frankvnk	0:0c037aff5039	32
frankvnk	0:0c037aff5039	33
frankvnk	0:0c037aff5039	34	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	35	// CONFIGURATION
frankvnk	0:0c037aff5039	36	// These values can be changed to alter the behavior of the spectrum display.
frankvnk	0:0c037aff5039	37	// KL25Z limitations
frankvnk	0:0c037aff5039	38	// -----------------
frankvnk	0:0c037aff5039	39	// - When used with the Spectrogram python script :
frankvnk	0:0c037aff5039	40	// There is a substantial time lag between the music and the screen output.
frankvnk	2:035d551759a5	41	// Max allowed SAMPLE_RATE_HZ is 40000
frankvnk	2:035d551759a5	42	// Max allowed FFT_SIZE is 64
frankvnk	0:0c037aff5039	43	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	44
frankvnk	2:035d551759a5	45	int SLOWDOWN = 4; // Create an optical delay in spectrumLoop - useful when only one RGB led is used.
frankvnk	0:0c037aff5039	46	// Only active when nonzero.
frankvnk	0:0c037aff5039	47	// A value >= 1000 and <= 1000 + PIXEL_COUNT fixes the output to a single frequency
frankvnk	0:0c037aff5039	48	// window = a single color.
frankvnk	0:0c037aff5039	49	int SAMPLE_RATE_HZ = 40000; // Sample rate of the audio in hertz.
frankvnk	2:035d551759a5	50	float SPECTRUM_MIN_DB = 30.0; // Audio intensity (in decibels) that maps to low LED brightness.
frankvnk	1:736b34e0f484	51	float SPECTRUM_MAX_DB = 80.0; // Audio intensity (in decibels) that maps to high LED brightness.
frankvnk	0:0c037aff5039	52	int LEDS_ENABLED = 1; // Control if the LED's should display the spectrum or not. 1 is true, 0 is false.
frankvnk	0:0c037aff5039	53	// Useful for turning the LED display on and off with commands from the serial port.
frankvnk	1:736b34e0f484	54	const int FFT_SIZE = 64; // Size of the FFT.
frankvnk	1:736b34e0f484	55	const int PIXEL_COUNT = 32; // Number of pixels. You should be able to increase this without
frankvnk	0:0c037aff5039	56	// any other changes to the program.
frankvnk	0:0c037aff5039	57	const int MAX_CHARS = 65; // Max size of the input command buffer
frankvnk	0:0c037aff5039	58
frankvnk	0:0c037aff5039	59	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	60	// INTERNAL STATE
frankvnk	0:0c037aff5039	61	// These shouldn't be modified unless you know what you're doing.
frankvnk	0:0c037aff5039	62	////////////////////////////////////////////////////////////////////////////////
frankvnk	2:035d551759a5	63	const static arm_cfft_instance_f32 *S;
frankvnk	0:0c037aff5039	64	Ticker samplingTimer;
frankvnk	0:0c037aff5039	65	float samples[FFT_SIZE*2];
frankvnk	0:0c037aff5039	66	float magnitudes[FFT_SIZE];
frankvnk	0:0c037aff5039	67	int sampleCounter = 0;
frankvnk	0:0c037aff5039	68	char commandBuffer[MAX_CHARS];
frankvnk	0:0c037aff5039	69	float frequencyWindow[PIXEL_COUNT+1];
frankvnk	0:0c037aff5039	70	float hues[PIXEL_COUNT];
frankvnk	0:0c037aff5039	71	bool commandRecv = 0;
frankvnk	0:0c037aff5039	72	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	73	// UTILITY FUNCTIONS
frankvnk	0:0c037aff5039	74	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	75
frankvnk	0:0c037aff5039	76	void rxisr() {
frankvnk	0:0c037aff5039	77	char c = pc.getc();
frankvnk	0:0c037aff5039	78	// Add any characters that aren't the end of a command (semicolon) to the input buffer.
frankvnk	0:0c037aff5039	79	if (c != ';') {
frankvnk	0:0c037aff5039	80	c = toupper(c);
frankvnk	0:0c037aff5039	81	strncat(commandBuffer, &c, 1);
frankvnk	0:0c037aff5039	82	} else {
frankvnk	0:0c037aff5039	83	// Parse the command because an end of command token was encountered.
frankvnk	0:0c037aff5039	84	commandRecv = 1;
frankvnk	0:0c037aff5039	85	}
frankvnk	0:0c037aff5039	86	}
frankvnk	0:0c037aff5039	87
frankvnk	0:0c037aff5039	88	// Compute the average magnitude of a target frequency window vs. all other frequencies.
frankvnk	0:0c037aff5039	89	void windowMean(float* magnitudes, int lowBin, int highBin, float* windowMean, float* otherMean)
frankvnk	0:0c037aff5039	90	{
frankvnk	0:0c037aff5039	91	*windowMean = 0;
frankvnk	0:0c037aff5039	92	*otherMean = 0;
frankvnk	0:0c037aff5039	93	// Notice the first magnitude bin is skipped because it represents the
frankvnk	0:0c037aff5039	94	// average power of the signal.
frankvnk	0:0c037aff5039	95	for (int i = 1; i < FFT_SIZE/2; ++i) {
frankvnk	0:0c037aff5039	96	if (i >= lowBin && i <= highBin) {
frankvnk	0:0c037aff5039	97	*windowMean += magnitudes[i];
frankvnk	0:0c037aff5039	98	} else {
frankvnk	0:0c037aff5039	99	*otherMean += magnitudes[i];
frankvnk	0:0c037aff5039	100	}
frankvnk	0:0c037aff5039	101	}
frankvnk	0:0c037aff5039	102	*windowMean /= (highBin - lowBin) + 1;
frankvnk	0:0c037aff5039	103	*otherMean /= (FFT_SIZE / 2 - (highBin - lowBin));
frankvnk	0:0c037aff5039	104	}
frankvnk	0:0c037aff5039	105
frankvnk	0:0c037aff5039	106	// Convert a frequency to the appropriate FFT bin it will fall within.
frankvnk	0:0c037aff5039	107	int frequencyToBin(float frequency)
frankvnk	0:0c037aff5039	108	{
frankvnk	0:0c037aff5039	109	float binFrequency = float(SAMPLE_RATE_HZ) / float(FFT_SIZE);
frankvnk	0:0c037aff5039	110	return int(frequency / binFrequency);
frankvnk	0:0c037aff5039	111	}
frankvnk	0:0c037aff5039	112
frankvnk	0:0c037aff5039	113
frankvnk	0:0c037aff5039	114	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	115	// SPECTRUM DISPLAY FUNCTIONS
frankvnk	0:0c037aff5039	116	///////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	117
frankvnk	0:0c037aff5039	118	void spectrumSetup()
frankvnk	0:0c037aff5039	119	{
frankvnk	0:0c037aff5039	120	// Set the frequency window values by evenly dividing the possible frequency
frankvnk	0:0c037aff5039	121	// spectrum across the number of neo pixels.
frankvnk	0:0c037aff5039	122	float windowSize = (SAMPLE_RATE_HZ / 2.0) / float(PIXEL_COUNT);
frankvnk	0:0c037aff5039	123	for (int i = 0; i < PIXEL_COUNT+1; ++i) {
frankvnk	0:0c037aff5039	124	frequencyWindow[i] = i*windowSize;
frankvnk	0:0c037aff5039	125	}
frankvnk	0:0c037aff5039	126	// Evenly spread hues across all pixels.
frankvnk	0:0c037aff5039	127	for (int i = 0; i < PIXEL_COUNT; ++i) {
frankvnk	0:0c037aff5039	128	hues[i] = 360.0*(float(i)/float(PIXEL_COUNT-1));
frankvnk	0:0c037aff5039	129	}
frankvnk	0:0c037aff5039	130	}
frankvnk	0:0c037aff5039	131
frankvnk	0:0c037aff5039	132	void spectrumLoop()
frankvnk	0:0c037aff5039	133	{
frankvnk	0:0c037aff5039	134	// Update each LED based on the intensity of the audio
frankvnk	0:0c037aff5039	135	// in the associated frequency window.
frankvnk	0:0c037aff5039	136	static int SLrpt = 0, SLpixcnt = 0;
frankvnk	0:0c037aff5039	137	int SLpixend = 0;
frankvnk	0:0c037aff5039	138	float intensity, otherMean;
frankvnk	0:0c037aff5039	139	if(SLOWDOWN != 0)
frankvnk	0:0c037aff5039	140	{
frankvnk	0:0c037aff5039	141	if(SLOWDOWN >= 1000)
frankvnk	0:0c037aff5039	142	{
frankvnk	0:0c037aff5039	143	if(SLOWDOWN <= (1000 + PIXEL_COUNT-1))
frankvnk	0:0c037aff5039	144	{
frankvnk	0:0c037aff5039	145	SLpixcnt = SLOWDOWN - 1000;
frankvnk	0:0c037aff5039	146	SLrpt = 0;
frankvnk	0:0c037aff5039	147	SLpixend = SLpixcnt + 1;
frankvnk	0:0c037aff5039	148	}
frankvnk	0:0c037aff5039	149	else
frankvnk	0:0c037aff5039	150	SLOWDOWN = 0;
frankvnk	0:0c037aff5039	151	}
frankvnk	0:0c037aff5039	152	else
frankvnk	0:0c037aff5039	153	{
frankvnk	0:0c037aff5039	154	SLrpt++;
frankvnk	0:0c037aff5039	155	if (SLrpt >= SLOWDOWN)
frankvnk	0:0c037aff5039	156	{
frankvnk	0:0c037aff5039	157	SLrpt = 0;
frankvnk	0:0c037aff5039	158	SLpixcnt = SLpixcnt < PIXEL_COUNT-1 ? ++SLpixcnt : 0;
frankvnk	0:0c037aff5039	159	}
frankvnk	0:0c037aff5039	160	SLpixend = SLpixcnt + 1;
frankvnk	0:0c037aff5039	161	}
frankvnk	0:0c037aff5039	162	}
frankvnk	0:0c037aff5039	163	else
frankvnk	0:0c037aff5039	164	{
frankvnk	0:0c037aff5039	165	SLpixcnt = 0;
frankvnk	0:0c037aff5039	166	SLrpt = 0;
frankvnk	0:0c037aff5039	167	SLpixend = PIXEL_COUNT;
frankvnk	0:0c037aff5039	168	}
frankvnk	0:0c037aff5039	169	for (int i = SLpixcnt; i < SLpixend; ++i) {
frankvnk	0:0c037aff5039	170	windowMean(magnitudes,
frankvnk	0:0c037aff5039	171	frequencyToBin(frequencyWindow[i]),
frankvnk	0:0c037aff5039	172	frequencyToBin(frequencyWindow[i+1]),
frankvnk	0:0c037aff5039	173	&intensity,
frankvnk	0:0c037aff5039	174	&otherMean);
frankvnk	0:0c037aff5039	175	// Convert intensity to decibels.
frankvnk	0:0c037aff5039	176	intensity = 20.0*log10(intensity);
frankvnk	0:0c037aff5039	177	// Scale the intensity and clamp between 0 and 1.0.
frankvnk	0:0c037aff5039	178	intensity -= SPECTRUM_MIN_DB;
frankvnk	0:0c037aff5039	179	intensity = intensity < 0.0 ? 0.0 : intensity;
frankvnk	0:0c037aff5039	180	intensity /= (SPECTRUM_MAX_DB-SPECTRUM_MIN_DB);
frankvnk	0:0c037aff5039	181	intensity = intensity > 1.0 ? 1.0 : intensity;
frankvnk	0:0c037aff5039	182	led.hsi2rgbw(hues[i], 1.0, intensity);
frankvnk	0:0c037aff5039	183	}
frankvnk	0:0c037aff5039	184	}
frankvnk	0:0c037aff5039	185
frankvnk	0:0c037aff5039	186
frankvnk	0:0c037aff5039	187	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	188	// SAMPLING FUNCTIONS
frankvnk	0:0c037aff5039	189	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	190
frankvnk	0:0c037aff5039	191	void samplingCallback()
frankvnk	0:0c037aff5039	192	{
frankvnk	0:0c037aff5039	193	// Read from the ADC and store the sample data
frankvnk	1:736b34e0f484	194	samples[sampleCounter] = (1023 * Audio) - 511.0f;
frankvnk	0:0c037aff5039	195	// Complex FFT functions require a coefficient for the imaginary part of the input.
frankvnk	0:0c037aff5039	196	// Since we only have real data, set this coefficient to zero.
frankvnk	0:0c037aff5039	197	samples[sampleCounter+1] = 0.0;
frankvnk	0:0c037aff5039	198	// Update sample buffer position and stop after the buffer is filled
frankvnk	0:0c037aff5039	199	sampleCounter += 2;
frankvnk	0:0c037aff5039	200	if (sampleCounter >= FFT_SIZE*2) {
frankvnk	0:0c037aff5039	201	samplingTimer.detach();
frankvnk	0:0c037aff5039	202	}
frankvnk	0:0c037aff5039	203	}
frankvnk	0:0c037aff5039	204
frankvnk	0:0c037aff5039	205	void samplingBegin()
frankvnk	0:0c037aff5039	206	{
frankvnk	0:0c037aff5039	207	// Reset sample buffer position and start callback at necessary rate.
frankvnk	0:0c037aff5039	208	sampleCounter = 0;
frankvnk	0:0c037aff5039	209	samplingTimer.attach_us(&samplingCallback, 1000000/SAMPLE_RATE_HZ);
frankvnk	0:0c037aff5039	210	}
frankvnk	0:0c037aff5039	211
frankvnk	0:0c037aff5039	212	bool samplingIsDone()
frankvnk	0:0c037aff5039	213	{
frankvnk	0:0c037aff5039	214	return sampleCounter >= FFT_SIZE*2;
frankvnk	0:0c037aff5039	215	}
frankvnk	0:0c037aff5039	216
frankvnk	0:0c037aff5039	217
frankvnk	0:0c037aff5039	218	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	219	// COMMAND PARSING FUNCTIONS
frankvnk	0:0c037aff5039	220	// These functions allow parsing simple commands input on the serial port.
frankvnk	0:0c037aff5039	221	// Commands allow reading and writing variables that control the device.
frankvnk	0:0c037aff5039	222	//
frankvnk	0:0c037aff5039	223	// All commands must end with a semicolon character.
frankvnk	0:0c037aff5039	224	//
frankvnk	0:0c037aff5039	225	// Example commands are:
frankvnk	0:0c037aff5039	226	// GET SAMPLE_RATE_HZ;
frankvnk	0:0c037aff5039	227	// - Get the sample rate of the device.
frankvnk	0:0c037aff5039	228	// SET SAMPLE_RATE_HZ 400;
frankvnk	0:0c037aff5039	229	// - Set the sample rate of the device to 400 hertz.
frankvnk	0:0c037aff5039	230	//
frankvnk	0:0c037aff5039	231	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	232
frankvnk	0:0c037aff5039	233	void parseCommand(char* command)
frankvnk	0:0c037aff5039	234	{
frankvnk	0:0c037aff5039	235	if (strcmp(command, "GET MAGNITUDES") == 0) {
frankvnk	0:0c037aff5039	236	for (int i = 0; i < FFT_SIZE; ++i) {
frankvnk	0:0c037aff5039	237	printf("%f\r\n", magnitudes[i]);
frankvnk	0:0c037aff5039	238	}
frankvnk	0:0c037aff5039	239	} else if (strcmp(command, "GET SAMPLES") == 0) {
frankvnk	0:0c037aff5039	240	for (int i = 0; i < FFT_SIZE*2; i+=2) {
frankvnk	0:0c037aff5039	241	printf("%f\r\n", samples[i]);
frankvnk	0:0c037aff5039	242	}
frankvnk	0:0c037aff5039	243	} else if (strcmp(command, "GET FFT_SIZE") == 0) {
frankvnk	0:0c037aff5039	244	printf("%d\r\n", FFT_SIZE);
frankvnk	0:0c037aff5039	245	} else if (strcmp(command, "GET SAMPLE_RATE_HZ") == 0) {
frankvnk	0:0c037aff5039	246	printf("%d\r\n", SAMPLE_RATE_HZ);
frankvnk	0:0c037aff5039	247	} else if (strstr(command, "SET SAMPLE_RATE_HZ") != NULL) {
frankvnk	0:0c037aff5039	248	SAMPLE_RATE_HZ = (typeof(SAMPLE_RATE_HZ)) atof(command+(sizeof("SET SAMPLE_RATE_HZ")-1));
frankvnk	0:0c037aff5039	249	} else if (strcmp(command, "GET LEDS_ENABLED") == 0) {
frankvnk	0:0c037aff5039	250	printf("%d\r\n", LEDS_ENABLED);
frankvnk	0:0c037aff5039	251	} else if (strstr(command, "SET LEDS_ENABLED") != NULL) {
frankvnk	0:0c037aff5039	252	LEDS_ENABLED = (typeof(LEDS_ENABLED)) atof(command+(sizeof("SET LEDS_ENABLED")-1));
frankvnk	0:0c037aff5039	253	} else if (strcmp(command, "GET SPECTRUM_MIN_DB") == 0) {
frankvnk	0:0c037aff5039	254	printf("%f\r\n", SPECTRUM_MIN_DB);
frankvnk	0:0c037aff5039	255	} else if (strstr(command, "SET SPECTRUM_MIN_DB") != NULL) {
frankvnk	0:0c037aff5039	256	SPECTRUM_MIN_DB = (typeof(SPECTRUM_MIN_DB)) atof(command+(sizeof("SET SPECTRUM_MIN_DB")-1));
frankvnk	0:0c037aff5039	257	} else if (strcmp(command, "GET SPECTRUM_MAX_DB") == 0) {
frankvnk	0:0c037aff5039	258	printf("%f\r\n", SPECTRUM_MAX_DB);
frankvnk	0:0c037aff5039	259	} else if (strstr(command, "SET SPECTRUM_MAX_DB") != NULL) {
frankvnk	0:0c037aff5039	260	SPECTRUM_MAX_DB = (typeof(SPECTRUM_MAX_DB)) atof(command+(sizeof("SET SPECTRUM_MAX_DB")-1));
frankvnk	0:0c037aff5039	261	} else if (strcmp(command, "GET SLOWDOWN") == 0) {
frankvnk	0:0c037aff5039	262	printf("%d\r\n", SLOWDOWN);
frankvnk	0:0c037aff5039	263	} else if (strstr(command, "SET SLOWDOWN") != NULL) {
frankvnk	0:0c037aff5039	264	SLOWDOWN = (typeof(SLOWDOWN)) atoi(command+(sizeof("SET SLOWDOWN")-1));
frankvnk	0:0c037aff5039	265	}
frankvnk	0:0c037aff5039	266
frankvnk	0:0c037aff5039	267	// Update spectrum display values if sample rate was changed.
frankvnk	0:0c037aff5039	268	if (strstr(command, "SET SAMPLE_RATE_HZ ") != NULL) {
frankvnk	0:0c037aff5039	269	spectrumSetup();
frankvnk	0:0c037aff5039	270	}
frankvnk	0:0c037aff5039	271
frankvnk	0:0c037aff5039	272	// Turn off the LEDs if the state changed.
frankvnk	0:0c037aff5039	273	if (LEDS_ENABLED == 0) {
frankvnk	0:0c037aff5039	274	}
frankvnk	0:0c037aff5039	275	}
frankvnk	0:0c037aff5039	276
frankvnk	0:0c037aff5039	277	void parserLoop()
frankvnk	0:0c037aff5039	278	{
frankvnk	0:0c037aff5039	279	// Process any incoming characters from the serial port
frankvnk	0:0c037aff5039	280	while (pc.readable()) {
frankvnk	0:0c037aff5039	281	char c = pc.getc();
frankvnk	0:0c037aff5039	282	// Add any characters that aren't the end of a command (semicolon) to the input buffer.
frankvnk	0:0c037aff5039	283	if (c != ';') {
frankvnk	0:0c037aff5039	284	c = toupper(c);
frankvnk	0:0c037aff5039	285	strncat(commandBuffer, &c, 1);
frankvnk	0:0c037aff5039	286	} else {
frankvnk	0:0c037aff5039	287	// Parse the command because an end of command token was encountered.
frankvnk	0:0c037aff5039	288	parseCommand(commandBuffer);
frankvnk	0:0c037aff5039	289	// Clear the input buffer
frankvnk	0:0c037aff5039	290	memset(commandBuffer, 0, sizeof(commandBuffer));
frankvnk	0:0c037aff5039	291	}
frankvnk	0:0c037aff5039	292	}
frankvnk	0:0c037aff5039	293	}
frankvnk	0:0c037aff5039	294
frankvnk	0:0c037aff5039	295	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	296	// MAIN FUNCTION
frankvnk	0:0c037aff5039	297	////////////////////////////////////////////////////////////////////////////////
frankvnk	0:0c037aff5039	298
frankvnk	0:0c037aff5039	299	int main()
frankvnk	0:0c037aff5039	300	{
frankvnk	0:0c037aff5039	301	NVIC_set_all_irq_priorities(1);
frankvnk	0:0c037aff5039	302	NVIC_SetPriority(UART0_IRQn, 0);
frankvnk	0:0c037aff5039	303	// Set up serial port.
frankvnk	0:0c037aff5039	304	pc.baud (38400);
frankvnk	0:0c037aff5039	305	pc.attach(&rxisr);
frankvnk	0:0c037aff5039	306	#ifndef RGBW_ext
frankvnk	0:0c037aff5039	307	led.invertpwm(1); //On-board KL25Z RGB LED uses common anode.
frankvnk	0:0c037aff5039	308	#endif
frankvnk	0:0c037aff5039	309	// Clear the input command buffer
frankvnk	0:0c037aff5039	310	memset(commandBuffer, 0, sizeof(commandBuffer));
frankvnk	0:0c037aff5039	311
frankvnk	0:0c037aff5039	312	// Initialize spectrum display
frankvnk	0:0c037aff5039	313	spectrumSetup();
frankvnk	0:0c037aff5039	314
frankvnk	0:0c037aff5039	315	// Begin sampling audio
frankvnk	0:0c037aff5039	316	samplingBegin();
frankvnk	0:0c037aff5039	317
frankvnk	2:035d551759a5	318	// Init arm_ccft_32
frankvnk	2:035d551759a5	319	switch (FFT_SIZE)
frankvnk	2:035d551759a5	320	{
frankvnk	2:035d551759a5	321	case 16:
frankvnk	2:035d551759a5	322	S = & arm_cfft_sR_f32_len16;
frankvnk	2:035d551759a5	323	break;
frankvnk	2:035d551759a5	324	case 32:
frankvnk	2:035d551759a5	325	S = & arm_cfft_sR_f32_len32;
frankvnk	2:035d551759a5	326	break;
frankvnk	2:035d551759a5	327	case 64:
frankvnk	2:035d551759a5	328	S = & arm_cfft_sR_f32_len64;
frankvnk	2:035d551759a5	329	break;
frankvnk	2:035d551759a5	330	case 128:
frankvnk	2:035d551759a5	331	S = & arm_cfft_sR_f32_len128;
frankvnk	2:035d551759a5	332	break;
frankvnk	2:035d551759a5	333	case 256:
frankvnk	2:035d551759a5	334	S = & arm_cfft_sR_f32_len256;
frankvnk	2:035d551759a5	335	break;
frankvnk	2:035d551759a5	336	case 512:
frankvnk	2:035d551759a5	337	S = & arm_cfft_sR_f32_len512;
frankvnk	2:035d551759a5	338	break;
frankvnk	2:035d551759a5	339	case 1024:
frankvnk	2:035d551759a5	340	S = & arm_cfft_sR_f32_len1024;
frankvnk	2:035d551759a5	341	break;
frankvnk	2:035d551759a5	342	case 2048:
frankvnk	2:035d551759a5	343	S = & arm_cfft_sR_f32_len2048;
frankvnk	2:035d551759a5	344	break;
frankvnk	2:035d551759a5	345	case 4096:
frankvnk	2:035d551759a5	346	S = & arm_cfft_sR_f32_len4096;
frankvnk	2:035d551759a5	347	break;
frankvnk	2:035d551759a5	348	}
frankvnk	2:035d551759a5	349
frankvnk	0:0c037aff5039	350	while(1) {
frankvnk	0:0c037aff5039	351	// Calculate FFT if a full sample is available.
frankvnk	0:0c037aff5039	352	if (samplingIsDone()) {
frankvnk	0:0c037aff5039	353	// Run FFT on sample data.
frankvnk	2:035d551759a5	354	// Run FFT on sample data.
frankvnk	2:035d551759a5	355	arm_cfft_f32(S, samples, 0, 1);
frankvnk	0:0c037aff5039	356	// Calculate magnitude of complex numbers output by the FFT.
frankvnk	0:0c037aff5039	357	arm_cmplx_mag_f32(samples, magnitudes, FFT_SIZE);
frankvnk	0:0c037aff5039	358
frankvnk	0:0c037aff5039	359	if (LEDS_ENABLED == 1) {
frankvnk	0:0c037aff5039	360	spectrumLoop();
frankvnk	0:0c037aff5039	361	}
frankvnk	0:0c037aff5039	362
frankvnk	0:0c037aff5039	363	// Restart audio sampling.
frankvnk	0:0c037aff5039	364	samplingBegin();
frankvnk	0:0c037aff5039	365	}
frankvnk	0:0c037aff5039	366
frankvnk	0:0c037aff5039	367	// Parse any pending commands.
frankvnk	0:0c037aff5039	368	if(commandRecv) {
frankvnk	0:0c037aff5039	369	// pc.attach(NULL);
frankvnk	0:0c037aff5039	370	parseCommand(commandBuffer);
frankvnk	0:0c037aff5039	371	commandRecv = 0;
frankvnk	0:0c037aff5039	372	// Clear the input buffer
frankvnk	0:0c037aff5039	373	memset(commandBuffer, 0, sizeof(commandBuffer));
frankvnk	0:0c037aff5039	374	// pc.attach(&rxisr);
frankvnk	0:0c037aff5039	375	}
frankvnk	0:0c037aff5039	376	}
frankvnk	0:0c037aff5039	377	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	25 Feb 2014
Imports:	309
Forks:	3
Commits:	3
Dependents:	0
Dependencies:	5
Followers:	9

The code in this repository is Apache licensed.