You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
OpenAudio_ArduinoLibrary/examples/BasicGain_Float/BasicGain_Float.ino

106 lines
5.5 KiB

/*
BasicGain
Created: Chip Audette, Nov 2016
Purpose: Process audio by applying gain.
Demonstrates audio processing using floating point data type.
Uses Teensy Audio Adapter.
Assumes microphones (or whatever) are attached to the LINE IN (stereo)
MIT License. use at your own risk.
*/
//These are the includes from the Teensy Audio Library
#include <Audio.h> //Teensy Audio Librarya
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>
#include <OpenAudio_ArduinoLibrary.h> //for AudioConvert_I16toF32, AudioConvert_F32toI16, and AudioEffectGain_F32
//create audio library objects for handling the audio
AudioControlSGTL5000 sgtl5000_1; //controller for the Teensy Audio Board
AudioInputI2S i2s_in; //Digital audio *from* the Teensy Audio Board ADC. Sends Int16. Stereo.
AudioOutputI2S i2s_out; //Digital audio *to* the Teensy Audio Board DAC. Expects Int16. Stereo
AudioConvert_I16toF32 int2Float1, int2Float2; //Converts Int16 to Float. See class in AudioStream_F32.h
AudioConvert_F32toI16 float2Int1, float2Int2; //Converts Float to Int16. See class in AudioStream_F32.h
AudioEffectGain_F32 gain1, gain2; //Applies digital gain to audio data. Expected Float data.
//Make all of the audio connections
AudioConnection patchCord1(i2s_in, 0, int2Float1, 0); //connect the Left input to the Left Int->Float converter
AudioConnection patchCord2(i2s_in, 1, int2Float2, 0); //connect the Right input to the Right Int->Float converter
AudioConnection_F32 patchCord10(int2Float1, 0, gain1, 0); //Left. makes Float connections between objects
AudioConnection_F32 patchCord11(int2Float2, 0, gain2, 0); //Right. makes Float connections between objects
AudioConnection_F32 patchCord12(gain1, 0, float2Int1, 0); //Left. makes Float connections between objects
AudioConnection_F32 patchCord13(gain2, 0, float2Int2, 0); //Right. makes Float connections between objects
AudioConnection patchCord20(float2Int1, 0, i2s_out, 0); //connect the Left float processor to the Left output
AudioConnection patchCord21(float2Int2, 0, i2s_out, 1); //connect the Right float processor to the Right output
// which input on the audio shield will be used?
const int myInput = AUDIO_INPUT_LINEIN;
//const int myInput = AUDIO_INPUT_MIC;
//I have a potentiometer on the Teensy Audio Board
#define POT_PIN A1 //potentiometer is tied to this pin
// define the setup() function, the function that is called once when the device is booting
void setup() {
Serial.begin(115200); //open the USB serial link to enable debugging messages
delay(500); //give the computer's USB serial system a moment to catch up.
Serial.println("Teensy Hearing Aid: BasicGain_Float..."); //identify myself over the USB serial
// Audio connections require memory, and the record queue
// uses this memory to buffer incoming audio.
AudioMemory(10); //allocate Int16 audio data blocks
AudioMemory_F32(10); //allocate Float32 audio data blocks
// Enable the audio shield, select input, and enable output
sgtl5000_1.enable(); //start the audio board
sgtl5000_1.inputSelect(myInput); //choose line-in or mic-in
sgtl5000_1.volume(0.8); //volume can be 0.0 to 1.0. 0.5 seems to be the usual default.
sgtl5000_1.lineInLevel(10,10); //level can be 0 to 15. 5 is the Teensy Audio Library's default
sgtl5000_1.adcHighPassFilterDisable(); //reduces noise. https://forum.pjrc.com/threads/27215-24-bit-audio-boards?p=78831&viewfull=1#post78831
// setup any other other features
pinMode(POT_PIN, INPUT); //set the potentiometer's input pin as an INPUT
} //end setup()
// define the loop() function, the function that is repeated over and over for the life of the device
unsigned long updatePeriod_millis = 100; //how many milliseconds between updating gain reading?
unsigned long lastUpdate_millis = 0;
unsigned long curTime_millis = 0;
int prev_gain_dB = 0;
void loop() {
//choose to sleep ("wait for interrupt") instead of spinning our wheels doing nothing but consuming power
asm(" WFI"); //ARM-specific. Will wake on next interrupt. The audio library issues tons of interrupts, so we wake up often.
//has enough time passed to try updating the GUI?
curTime_millis = millis(); //what time is it right now
if (curTime_millis < lastUpdate_millis) lastUpdate_millis = 0; //handle wrap-around of the clock
if ((curTime_millis - lastUpdate_millis) > updatePeriod_millis) { //is it time to update the user interface?
//read potentiometer
float val = float(analogRead(POT_PIN)) / 1024.0; //0.0 to 1.0
val = 0.1*(float)((int)(10.0*val + 0.5)); //quantize so that it doesn't chatter
//compute desired digital gain
const float min_gain_dB = -20.0, max_gain_dB = 40.0; //set desired gain range
float gain_dB = min_gain_dB + (max_gain_dB - min_gain_dB)*val; //computed desired gain value in dB
//if the gain is different than before, set the new gain value
if (abs(gain_dB - prev_gain_dB) > 1.0) { //is it different than before
gain1.setGain_dB(gain_dB); //set the gain of the Left-channel gain processor
gain2.setGain_dB(gain_dB); //set the gain of the Right-channel gain processor
Serial.print("Digital Gain dB = "); Serial.println(gain_dB); //print text to Serial port for debugging
prev_gain_dB = gain_dB; //we will use this value the next time around
}
lastUpdate_millis = curTime_millis; //we will use this value the next time around.
} // end if
} //end loop();