ESP32_Oscilloscope/ESP32_Oscilloscope.ino

@@ -210,7 +210,6 @@ void core1_task(void *pvParameters)
       {
         if (stop_change)
         {
-          // TODO the enable function causes an esp32 deadlock
           //i2s_adc_enable(I2S_NUM_0);
           i2s_zero_dma_buffer(I2S_NUM_0);
           stop_change = false;

ESP32_Oscilloscope/data_analysis.ino

@@ -78,15 +78,20 @@ void trigger_freq_analog(uint16_t *i2s_buffer,
   uint32_t trigger_index = 0;
 
   // get initial signal relative to the mean
-    bool previous_signal_side = (to_voltage(i2s_buffer[0]) > mean);
+  if (to_voltage(i2s_buffer[0]) > mean)
+  {
+    signal_side = true;
+  }
 
   // waveform repetitions calculation + get triggers time
   uint32_t wave_center = (max_v + min_v) / 2;
   for (uint32_t i = 1; i < BUFF_SIZE; i++)
   {
-        bool current_signal_side = (to_voltage(i2s_buffer[i]) > mean);
-
-        if (previous_signal_side && !current_signal_side)
+    if (signal_side && i2s_buffer[i] < wave_center - (wave_center - min_v) * 0.2)
+    {
+      signal_side = false;
+    }
+    else if (!signal_side && i2s_buffer[i] > wave_center + (max_v - wave_center) * 0.2)
     {
       freq++;
       if (trigger_count < trigger_num)
@@ -94,19 +99,10 @@ void trigger_freq_analog(uint16_t *i2s_buffer,
         trigger_temp[trigger_count] = i;
         trigger_count++;
       }
-        } else if (!previous_signal_side && current_signal_side)
-        {
-            freq++;
-            if (trigger_count < trigger_num)
-            {
-                trigger_temp[trigger_count] = i;
-                trigger_count++;
+      signal_side = true;
     }
   }
 
-        previous_signal_side = current_signal_side;
-    }
-
   // frequency calculation
   if (trigger_count < 2)
   {
@@ -176,6 +172,7 @@ void trigger_freq_digital(uint16_t *i2s_buffer,
                           float *pt_period,
                           uint32_t *pt_trigger0)
 {
+
   float freq = 0;
   float period = 0;
   bool signal_side = false;
@@ -185,7 +182,10 @@ void trigger_freq_digital(uint16_t *i2s_buffer,
   uint32_t trigger_index = 0;
 
   // get initial signal relative to the mean
-    bool previous_signal_side = (to_voltage(i2s_buffer[0]) > mean);
+  if (to_voltage(i2s_buffer[0]) > mean)
+  {
+    signal_side = true;
+  }
 
   // waveform repetitions calculation + get triggers time
   uint32_t wave_center = (max_v + min_v) / 2;
@@ -194,37 +194,38 @@ void trigger_freq_digital(uint16_t *i2s_buffer,
   {
     for (uint32_t i = 1; i < BUFF_SIZE; i++)
     {
-            bool current_signal_side = (to_voltage(i2s_buffer[i]) > mean);
-
-            if (previous_signal_side && !current_signal_side)
+      if (signal_side && i2s_buffer[i] < wave_center - (wave_center - min_v) * 0.2)
       {
+
         // signal was high, fell -> trigger if normal high
         if (trigger_count < trigger_num && normal_high)
         {
           trigger_temp[trigger_count] = i;
           trigger_count++;
         }
+
+        signal_side = false;
       }
-            else if (!previous_signal_side && current_signal_side)
+      else if (!signal_side && i2s_buffer[i] > wave_center + (max_v - wave_center) * 0.2)
       {
+        freq++;
+
         // signal was low, rose -> trigger if normal low
         if (trigger_count < trigger_num && !normal_high)
         {
           trigger_temp[trigger_count] = i;
           trigger_count++;
         }
+
+        signal_side = true;
+      }
     }
 
-            previous_signal_side = current_signal_side;
-        }
-
-        // frequency calculation
-        if (trigger_count > 1)
-        {
-            // simple frequency calculation fair enough for frequencies over 2khz (20hz resolution)
     freq = freq * 1000 / 50;
     period = (float)(sample_rate * 1000.0) / freq; // us
 
+    if (trigger_count > 1)
+    {
       // from 2000 to 80 hz -> uses mean of the periods for precision
       if (freq < 2000 && freq > 80)
       {

ESP32_Oscilloscope/i2s.ino

@@ -32,11 +32,9 @@ void ADC_Sampling(uint16_t *i2s_buff){
 }
 */
 void ADC_Sampling(uint16_t *i2s_buff){
-  size_t bytes_read;
-  for (int i = 0; i < B_MULT; i++) {
+  size_t bytes_read; for (int i = 0; i < B_MULT; i++) {
     i2s_read(I2S_NUM_0, (void*)&i2s_buff[i * NUM_SAMPLES], NUM_SAMPLES * sizeof(uint16_t), &bytes_read, portMAX_DELAY);
-    for(size_t ix = 0; ix < bytes_read/2; ix++)
-      i2s_buff[(i * NUM_SAMPLES) + ix] &= 0x0FFF; // 16bit to 12bit conversion 
+    for(size_t ix = 0; ix < bytes_read/2; ix++) i2s_buff[(i * NUM_SAMPLES) + ix] &= 0x0FFF; // 16bit to 12bit conversion 
   }
 }