Added ChatGPT suggested fixed for frequency calculation.

ESP32_Oscilloscope/ESP32_Oscilloscope.ino

@@ -210,6 +210,7 @@ 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

@@ -78,20 +78,15 @@ void trigger_freq_analog(uint16_t *i2s_buffer,
     uint32_t trigger_index = 0;
 
     // get initial signal relative to the mean
-  if (to_voltage(i2s_buffer[0]) > mean)
-  {
-    signal_side = true;
-  }
+    bool previous_signal_side = (to_voltage(i2s_buffer[0]) > mean);
 
     // waveform repetitions calculation + get triggers time
     uint32_t wave_center = (max_v + min_v) / 2;
     for (uint32_t i = 1; i < BUFF_SIZE; i++)
     {
-    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)
+        bool current_signal_side = (to_voltage(i2s_buffer[i]) > mean);
+
+        if (previous_signal_side && !current_signal_side)
         {
             freq++;
             if (trigger_count < trigger_num)
@@ -99,10 +94,19 @@ void trigger_freq_analog(uint16_t *i2s_buffer,
                 trigger_temp[trigger_count] = i;
                 trigger_count++;
             }
-      signal_side = true;
+        } else if (!previous_signal_side && current_signal_side)
+        {
+            freq++;
+            if (trigger_count < trigger_num)
+            {
+                trigger_temp[trigger_count] = i;
+                trigger_count++;
             }
         }
 
+        previous_signal_side = current_signal_side;
+    }
+
     // frequency calculation
     if (trigger_count < 2)
     {
@@ -172,7 +176,6 @@ 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;
@@ -182,10 +185,7 @@ void trigger_freq_digital(uint16_t *i2s_buffer,
     uint32_t trigger_index = 0;
 
     // get initial signal relative to the mean
-  if (to_voltage(i2s_buffer[0]) > mean)
-  {
-    signal_side = true;
-  }
+    bool previous_signal_side = (to_voltage(i2s_buffer[0]) > mean);
 
     // waveform repetitions calculation + get triggers time
     uint32_t wave_center = (max_v + min_v) / 2;
@@ -194,38 +194,37 @@ void trigger_freq_digital(uint16_t *i2s_buffer,
     {
         for (uint32_t i = 1; i < BUFF_SIZE; i++)
         {
-      if (signal_side && i2s_buffer[i] < wave_center - (wave_center - min_v) * 0.2)
-      {
+            bool current_signal_side = (to_voltage(i2s_buffer[i]) > mean);
 
+            if (previous_signal_side && !current_signal_side)
+            {
                 // 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 (!signal_side && i2s_buffer[i] > wave_center + (max_v - wave_center) * 0.2)
+            else if (!previous_signal_side && current_signal_side)
             {
-        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

@@ -32,9 +32,11 @@ 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 
   }
 }