Add an audio sweep. User defined start and end frequencies and length of time of sweep.

Audio.cpp

@@ -3590,3 +3590,108 @@ void AudioEffectChorus::update(void)
   }
 }
 
+
+/******************************************************************/
+
+//                A u d i o T o n e S w e e p
+// Written by Pete (El Supremo) Feb 2014
+
+
+boolean AudioToneSweep::begin(short t_amp,int t_lo,int t_hi,float t_time)
+{
+  double tone_tmp;
+  
+if(0) {
+  Serial.print("AudioToneSweep.begin(tone_amp = ");
+  Serial.print(t_amp);
+  Serial.print(", tone_lo = ");
+  Serial.print(t_lo);
+  Serial.print(", tone_hi = ");
+  Serial.print(t_hi);
+  Serial.print(", tone_time = ");
+  Serial.print(t_time,1);
+  Serial.println(")");
+}
+  tone_amp = 0;
+  if(t_amp < 0)return false;
+  if(t_lo < 1)return false;
+  if(t_hi < 1)return false;
+  if(t_hi >= 44100/2)return false;
+  if(t_lo >= 44100/2)return false;
+  if(t_time < 0)return false;
+  tone_lo = t_lo;
+  tone_hi = t_hi;
+  tone_phase = 0;
+
+  tone_amp = t_amp;
+  // Limit the output amplitude to prevent aliasing
+  // until I can figure out why this "overtops"
+  // above 29000.
+  if(tone_amp > 29000)tone_amp = 29000;
+  tone_tmp = tone_hi - tone_lo;
+  tone_sign = 1;
+  tone_freq = tone_lo*0x100000000LL;
+  if(tone_tmp < 0) {
+    tone_sign = -1;
+    tone_tmp = -tone_tmp;
+  }
+  tone_tmp = tone_tmp/t_time/44100.;
+  tone_incr = (tone_tmp * 0x100000000LL);
+  sweep_busy = 1;
+  return(true);
+}
+
+
+
+unsigned char AudioToneSweep::busy(void)
+{
+  return(sweep_busy);
+}
+
+int b_count = 0;
+void AudioToneSweep::update(void)
+{
+  audio_block_t *block;
+  short *bp;
+  int i;
+  
+  if(!sweep_busy)return;
+
+  //          L E F T  C H A N N E L  O N L Y
+  block = allocate();
+  if(block) {
+    bp = block->data;
+    // Generate the sweep
+    for(i = 0;i < AUDIO_BLOCK_SAMPLES;i++) {
+      *bp++ = (short)(( (short)(arm_sin_q31((uint32_t)((tone_phase >> 15)&0x7fffffff))>>16) *tone_amp) >> 16);
+      uint64_t tone_tmp = (0x400000000000LL * (int)((tone_freq >> 32)&0x7fffffff))/44100;
+
+      tone_phase +=  tone_tmp;
+      if(tone_phase & 0x800000000000LL)tone_phase &= 0x7fffffffffffLL;
+
+      if(tone_sign > 0) {
+        if((tone_freq >> 32) > tone_hi) {
+          sweep_busy = 0;
+          break;
+        }
+        tone_freq += tone_incr;
+      } else {
+        if((tone_freq >> 32) < tone_hi) {
+          sweep_busy = 0;
+
+          break;
+        }
+        tone_freq -= tone_incr;        
+      }
+    }
+    while(i < AUDIO_BLOCK_SAMPLES) {
+      *bp++ = 0;
+      i++;
+    }
+    b_count++;
+    // send the samples to the left channel
+    transmit(block,0);
+    release(block);
+    if(!sweep_busy)Serial.println(b_count);
+  }
+}

Audio.h

@@ -666,6 +666,30 @@ private:
 };
 
 
+/******************************************************************/
+
+//                A u d i o T o n e S w e e p
+// Written by Pete (El Supremo) Feb 2014
+
+class AudioToneSweep : public AudioStream
+{
+public:
+  AudioToneSweep(void) : 
+  AudioStream(0,NULL), sweep_busy(0)
+  { }
 
+  boolean begin(short t_amp,int t_lo,int t_hi,float t_time);
+  virtual void update(void);
+  unsigned char busy(void);
 
+private:
+  short tone_amp;
+  int tone_lo;
+  int tone_hi;
+  uint64_t tone_freq;
+  uint64_t tone_phase;
+  uint64_t tone_incr;
+  int tone_sign;
+  unsigned char sweep_busy;
+};