LeoUCDavis
New member
Hi
I'm trying to implement a function generator and a simple spectrum analyzer with the Teensy 3.1 using built-in ADC and DAC. I modified the code from this demo: https://www.youtube.com/watch?v=CblOUmK3oKM
Without the waveform synthesis module, the spectrum analyzer part runs fine. When I add the triangle wave synthesizer however, the "myFFT.available()" function call never returns true. I wonder if this is because of a coding error on my side or an inherent limitation on the computation capabilities of the Teensy.
Below is the code. Thanks!
I'm trying to implement a function generator and a simple spectrum analyzer with the Teensy 3.1 using built-in ADC and DAC. I modified the code from this demo: https://www.youtube.com/watch?v=CblOUmK3oKM
Without the waveform synthesis module, the spectrum analyzer part runs fine. When I add the triangle wave synthesizer however, the "myFFT.available()" function call never returns true. I wonder if this is because of a coding error on my side or an inherent limitation on the computation capabilities of the Teensy.
Below is the code. Thanks!
Code:
#include <Audio.h>
#include <Wire.h>
#include <SD.h>
#include <Adafruit_GFX.h> // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library
#include <SPI.h>
//SPI connections for Banggood 1.8" display
#define sclk 5
#define mosi 4
#define cs 2
#define dc 3
#define rst 1 // you can also connect this to the Arduino reset
// use HW SPI interface for TFT
//Adafruit_S6D02A1 tft = Adafruit_S6D02A1(cs, dc, rst);
// Option 1: use any pins but a little slower
Adafruit_ST7735 tft = Adafruit_ST7735(cs, dc, mosi, sclk, rst);
// Create the Audio components. These should be created in the
// order data flows, inputs/sources -> processing -> outputs
//
AudioSynthWaveform waveform1; //
AudioOutputAnalog dac1; //
AudioConnection c1(waveform1, dac1);
//Create the sampling components
AudioInputAnalog adc1(A1); // audio shield: mic or line-in
AudioAnalyzeFFT256 myFFT;
// Create Audio connections between the components
AudioConnection c2(adc1, myFFT);
void setup() {
// Audio connections require memory to work. For more
// detailed information, see the MemoryAndCpuUsage example
AudioMemory(12);
waveform1.begin(0.75, 400, WAVEFORM_TRIANGLE);
// If your TFT's plastic wrap has a Black Tab, use the following:
//tft.initR(INITR_BLACKTAB); // initialize a S6D02A1S chip, black tab
// If your TFT's plastic wrap has a Red Tab, use the following:
//tft.initR(INITR_REDTAB); // initialize a S6D02A1R chip, red tab
// If your TFT's plastic wrap has a Green Tab, use the following:
tft.initR(INITR_GREENTAB); // initialize a S6D02A1R chip, green tab
tft.setRotation(1);
Serial.println("init");
// SPI.setClockDivider(SPI_CLOCK_DIV2); // crank up the spi
uint16_t time = millis();
tft.fillScreen(ST7735_BLACK);
time = millis() - time;
Serial.println(time, DEC);
// delay(500);
// large block of text
tft.fillScreen(ST7735_BLACK);
tft.setCursor(0, 115);
tft.setTextColor(ST7735_WHITE);
tft.setTextWrap(true);
tft.print("Teensy Spectrum Analyser 2");
Serial.println("text successful");
delay(1000);
// pin 21 will select rapid vs animated display
pinMode(21, INPUT_PULLUP);
}
int count=0;
const int nsum[16] = {1, 1, 2, 2, 3, 4, 5, 6, 6, 8, 12, 14, 16, 20, 28, 24};
int peak[512];
int maximum[16];
unsigned long last_time = millis();
void loop() {
//while(1);
Serial.println("start");
if (myFFT.available()) {
Serial.println("fft complete");
int scale = 4;
// Alternatively we can implement an adjustable scale by a potentiometer connected to A2
//scale = 2 + (1023 - analogRead(A2)) / 7;
//Serial.print(" - ");
//Serial.print(scale);
//Serial.print(" ");
// graphing the bars
for (int16_t x=0; x < 160; x+=1) {
//tft.drawFastVLine(x, 0, myFFT.output[x]/scale, S6D02A1_GREEN);
int bar=abs(myFFT.output[x])/scale;
if (bar >110) bar=110;
if (bar > peak[x]) peak[x]=bar;
tft.drawFastVLine(x, 110-bar,bar, ST7735_MAGENTA);
// tft.drawFastVLine(x+1, 20, abs(myFFT.output[x]/scale), S6D02A1_GREEN);
tft.drawFastVLine(x, 0, 110-bar, ST7735_BLACK);
// tft.drawFastVLine(x+1, 20+abs(myFFT.output[x]/scale), 80, S6D02A1_BLACK);
tft.drawPixel(x,110-peak[x], ST7735_YELLOW);
// tft.drawFastVLine(x, 110-peak[x],bar, S6D02A1_BLUE);
if(peak[x]>0) peak[x]-=5;
}
Serial.println("display complete");
// Change this to if(1) for measurement output
if(1) {
/*
For PlaySynthMusic this produces:
Proc = 20 (21), Mem = 2 (8)
*/
if(millis() - last_time >= 5000) {
Serial.print("Proc = ");
Serial.print(AudioProcessorUsage());
Serial.print(" (");
Serial.print(AudioProcessorUsageMax());
Serial.print("), Mem = ");
Serial.print(AudioMemoryUsage());
Serial.print(" (");
Serial.print(AudioMemoryUsageMax());
Serial.println(")");
last_time = millis();
}
}
}
}
