Add Multi Channel ADC selection and example

examples/MultiChannelAdcStream/MultiChannelAdcStream.ino

@@ -0,0 +1,99 @@
+/*
+    AutoAnalogAudio streaming via DAC & ADC by TMRh20
+    Copyright (C) 2016  TMRh20 - tmrh20@gmail.com, github.com/TMRh20
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+  Auto Analog Audio (Automatic DAC, ADC & Timer) library
+
+  Features:
+  1. Very simple user interface to Arduino DUE DAC and ADC
+  2. PCM/WAV Audio/Analog Data playback using Arduino Due DAC
+  3. PCM/WAV Audio/Analog Data recording using Arduino Due ADC
+  4. Onboard timers drive the DAC & ADC automatically
+  5. Automatic sample rate/timer adjustment based on rate of user-driven data requests/input
+  6. Uses DMA (Direct Memory Access) to buffer DAC & ADC data
+
+  Auto Analog Audio Library Information:
+  http://github.com/TMRh20
+  http://tmrh20.blogspot.com
+
+**************************************************************************
+  Dual Pin ADC Sampling
+
+  Sample the ADC in chunks of 32-bytes at a defined sample rate
+  The first sample will be from pin A1, second from A0, 3rd from A1, etc...
+  See AnalogAudio_config.h to change the MAX_BUFFER_SIZE allowing larger chunks
+
+**************************************************************************
+*/
+
+#include <AutoAnalogAudio.h>
+AutoAnalog aaAudio;
+
+/*********************************************************/
+
+void setup() {
+
+  Serial.begin(115200);
+  Serial.println("Analog Audio Begin");
+
+  aaAudio.begin(1, 0);              //Setup aaAudio using ADC only
+  aaAudio.autoAdjust = 0;           //Disable auto adjust of timers
+  aaAudio.adcBitsPerSample = 12;    //Sample at 12-bits
+  aaAudio.setSampleRate(32);        //Get 32 samples every second
+
+  //AAAudio samples on analog pin A0 by default
+  //Enable sampling on two pins at once
+  aaAudio.enableAdcChannel(1);      //Channels correspond to pin numbers (A1 == channel 1)
+  //aaAudio.enableAdcChannel(2);    //Optionally enable a third channel on pin A2
+  //aaAudio.disableAdcChannel(0);   //Optionally disable pin A0 and only sample 1 pin
+
+  //Start loading ADC buffers
+  aaAudio.getADC();
+}
+
+/*********************************************************/
+
+void loop() {
+
+  // Get 32 samples from the ADC at the sample rate defined above
+  // Note: This function only blocks if the ADC is currently sampling and autoAdjust is set to 0
+  // As long as any additional code completes before the ADC is finished sampling, a continuous stream of ADC data
+  // at the defined sample rate will be available
+  aaAudio.getADC();
+
+  // Sum all the samples into a float
+  float pinA0Samples = 0.0;
+  float pinA1Samples = 0.0;
+  for (int i = 0; i < 32; i += 2) {
+    pinA1Samples += aaAudio.adcBuffer16[i];           //Samples from highest pin number (A1)
+    pinA0Samples += aaAudio.adcBuffer16[i + 1];       //Samples from next lowest pin number (A0)
+  }
+
+  // Divide the total by the number of samples
+  pinA1Samples /= 16.0;
+  pinA0Samples /= 16.0;
+
+  // This will print every second at a sample rate of 32 samples/second
+  Serial.print("Pin A1 Samples Total / Number of Samples == ");
+  Serial.println(pinA1Samples);
+  Serial.print("Pin A0 Samples Total / Number of Samples == ");
+  Serial.println(pinA0Samples);
+
+}
+
+/*********************************************************/
+

src/AutoAnalogAudio.cpp

@@ -77,6 +77,26 @@ void AutoAnalog::triggerADC(){
 
 
 
+}
+
+/****************************************************************************/
+
+void AutoAnalog::enableAdcChannel(uint8_t pinAx){
+
+    if(pinAx > 6){ return; }
+    pinAx = 7 - pinAx;    
+    ADC->ADC_CHER |= 1<< pinAx;
+
+}
+
+/****************************************************************************/
+
+void AutoAnalog::disableAdcChannel(uint8_t pinAx){
+
+    if(pinAx > 6){ return; }
+    pinAx = 7 - pinAx;    
+    ADC->ADC_CHDR |= 1<< pinAx;
+
 }
 
 /****************************************************************************/
@@ -208,15 +228,15 @@ void AutoAnalog::adcSetup(void){
     ADC->ADC_CGR = 0x15555555 ;   // All gains set to x1
     ADC->ADC_COR = 0x00000000 ;   // All offsets off
 
-    ADC->ADC_MR = (ADC->ADC_MR & 0xFF00FF00) | 1 << 2 | ADC_MR_TRGEN;//& ~ADC_MR_SLEEP & ~ADC_MR_FWUP // 1 = trig source TIO from TC0
+    ADC->ADC_MR = (ADC->ADC_MR & 0x0F00FF00) | 1 << 2 | ADC_MR_TRGEN;//& ~ADC_MR_SLEEP & ~ADC_MR_FWUP // 1 = trig source TIO from TC0
     //ADC->ADC_MR = (ADC->ADC_MR & 0xFF00FF00);
     //ADC->ADC_MR |= ADC_MR_LOWRES;
     //MR Prescalar = 255     ADCClock == 84mhz / ( (256) * 2) == ?? MIN is 1Mhz
     //ADC->ADC_MR |= 5 << 8; //Prescalar ? sets ADC Clock to 1,615,384.6 hz, 5 is 7mhz
     //ADC->ADC_MR |= 3 << 20; //Settling time, full is 17ADC Clocks, 411,764.7hz, 9 is 179487.2, 5
     //ADC->ADC_MR |= 1; //51470.6hz
 
-    ADC->ADC_PTCR=1;    
+    ADC->ADC_PTCR=ADC_PTCR_RXTEN;    
 }
 
 /****************************************************************************/

src/AutoAnalogAudio.h

@@ -132,6 +132,21 @@ class AutoAnalog
    **/
   uint8_t dacBitsPerSample;
 
+  /**
+   * Enable reads from the specified channel (pins A0-A6)
+   *
+   * Active ADC Channels will be read in numeric order, high to low
+   *
+   * @note Specify pins numerically: 0=A0, 1=A1, etc...
+   */
+  void enableAdcChannel(uint8_t pinAx);
+
+  /**
+   * Disable reads from the specified channel (pins A0-A6)
+   * @note Specify pins numerically: 0=A0, 1=A1, etc...
+   */
+  void disableAdcChannel(uint8_t pinAx);
+
   /**@}*/
 
 private:
@@ -262,6 +277,18 @@ class AutoAnalog
  *  This example demonstrates how to capture a steady stream of ADC data
  *
  *  See AnalogAudio_config.h to change the MAX_BUFFER_SIZE allowing larger chunks
+ */ 
+
+  /**
+ * @example MultiChannelAdcStream.ino
+ * <b>For Arduino Due</b><br>
+ *
+ * * Multi Channel ADC Sampling Example:
+ *
+ *  This example demonstrates how to capture a steady stream of ADC data on
+ *  multiple channels. Currently pins A0-A6 are supported.
+ *
+ *  See AnalogAudio_config.h to change the MAX_BUFFER_SIZE allowing larger chunks of data
  */ 
 
  /**
@@ -284,6 +311,7 @@ class AutoAnalog
  * - Uses DMA (Direct Memory Access) to buffer DAC & ADC data
  * - ADC & DAC: 8, 10 or 12-bit sampling
  * - Single channel or stereo output
+ * - Multi-channel ADC sampling
  * 
 
  *