3 files changed, 57 insertions, 6 deletions
diff --git a/source/adc.cpp b/source/adc.cpp
index 609ffce..f2903c3 100644
--- a/source/adc.cpp
+++ b/source/adc.cpp
@@ -45,12 +45,9 @@ constexpr static const GPTConfig gpt_config = {
 };
 
 static bool adc_is_read_finished = false;
-
-void adc_read_callback([[maybe_unused]] ADCDriver *driver)
-{
-    gptStopTimer(gptd);
-    adc_is_read_finished = true;
-}
+static adcsample_t *adc_current_buffer = nullptr;
+static size_t adc_current_buffer_size = 0;
+static adc::operation_t adc_operation_func = nullptr;
 
 namespace adc
 {
@@ -66,11 +63,31 @@ namespace adc
     adcsample_t *read(adcsample_t *buffer, size_t count)
     {
         adc_is_read_finished = false;
+        adc_group_config.circular = false;
         adcStartConversion(adcd, &adc_group_config, buffer, count);
         gptStartContinuous(gptd, 100); // 10kHz
         while (!adc_is_read_finished);
         return buffer;
     }
+
+    void read_start(operation_t operation_func, adcsample_t *buffer, size_t count)
+    {
+        adc_current_buffer = buffer;
+        adc_current_buffer_size = count;
+        adc_operation_func = operation_func;
+        adc_group_config.circular = true;
+        adcStartConversion(adcd, &adc_group_config, buffer, count);
+        gptStartContinuous(gptd, 100); // 10kHz
+    }
+    
+    void read_stop()
+    {
+        gptStopTimer(gptd);
+        adc_group_config.circular = false;
+        adc_current_buffer = nullptr;
+        adc_current_buffer_size = 0;
+        adc_operation_func = nullptr;
+    }
  
     void set_rate(rate r)
     {
@@ -107,3 +124,20 @@ namespace adc
     }
 }
 
+void adc_read_callback(ADCDriver *driver)
+{
+    if (!adc_group_config.circular) {
+        gptStopTimer(gptd);
+        adc_is_read_finished = true;
+    } else if (adc_operation_func != nullptr) {
+        auto half_size = adc_current_buffer_size / 2;
+        if (driver->state == ADC_ACTIVE) {
+            // Half full
+            adc_operation_func(adc_current_buffer, half_size);
+        } else if (driver->state == ADC_COMPLETE) {
+            // Second half full
+            adc_operation_func(adc_current_buffer + half_size, half_size);
+        }
+    }
+}
+
diff --git a/source/adc.hpp b/source/adc.hpp
index e026d0c..376b156 100644
--- a/source/adc.hpp
+++ b/source/adc.hpp
@@ -16,6 +16,8 @@
 
 namespace adc
 {
+    using operation_t = void (*)(adcsample_t *buffer, size_t count);
+
     enum class rate {
         R2P5,
         R6P5,
@@ -29,6 +31,8 @@ namespace adc
     
     void init();
     adcsample_t *read(adcsample_t *buffer, size_t count);
+    void read_start(operation_t operation_func, adcsample_t *buffer, size_t count);
+    void read_stop();
     void set_rate(rate r);
 }
 
diff --git a/source/main.cpp b/source/main.cpp
index b5ebf86..f1170a6 100644
--- a/source/main.cpp
+++ b/source/main.cpp
@@ -26,6 +26,8 @@ CC_ALIGN(CACHE_LINE_SIZE)
 static std::array<adcsample_t, CACHE_SIZE_ALIGN(adcsample_t, 2048)> adc_samples;
 static std::array<dacsample_t, CACHE_SIZE_ALIGN(dacsample_t, 2048)> dac_samples;
 
+static void signal_operate(adcsample_t *buffer, size_t count);
+
 int main()
 {
     halInit();
@@ -51,6 +53,12 @@ int main()
                         usbserial::write(adc_samples.data(), count * sizeof(adcsample_t));
                     }
                     break;
+                case 'R':
+                    adc::read_start(signal_operate, &adc_samples[0], adc_samples.size() * sizeof(adcsample_t));
+                    break;
+                case 'S':
+                    adc::read_stop();
+                    break;
                 case 'W':
                     if (usbserial::read(&cmd[1], 2) < 2)
                         break;
@@ -77,3 +85,8 @@ int main()
 	}
 }
 
+void signal_operate([[maybe_unused]] adcsample_t *buffer, [[maybe_unused]] size_t count)
+{
+
+}
+