Feat: add loop to main to read adc data

Refs: #4

src/main/esp32_eurorack_generic.c

@@ -1,11 +1,16 @@
 #include <stdio.h>
 
+#include "esp_attr.h"
 #include "esp_err.h"
 #include "esp_log.h"
 #include "esp_adc/adc_cali.h"
 #include "esp_adc/adc_cali_scheme.h"
 #include "esp_adc/adc_continuous.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/portmacro.h"
 #include "hal/adc_types.h"
+#include "soc/soc_caps.h"
 
 /* ADC input pins */
 #define ADC_INPUT_1_PIN 4
@@ -13,39 +18,59 @@
 #define ADC_INPUT_3_PIN 9 /* TODO Reroute from pin 46 to 9 on schematic, cant do ADC */
 #define ADC_INPUT_4_PIN 10
 
+#define ADC_READ_LEN 256
+
 /* ADC channels */
 static adc_channel_t channel[4] = {ADC_CHANNEL_3, ADC_CHANNEL_5, ADC_CHANNEL_8, ADC_CHANNEL_9};
 
+/* ADC handles */
+static adc_continuous_handle_t adc_handle;
+static adc_cali_handle_t adc_cali_handle;
+static TaskHandle_t adc_task_handle;
+
 static const char *TAG = "EERG";
 
 
+/* ADC conversion finished callback */
+static bool IRAM_ATTR adc_conv_cb(adc_continuous_handle_t handle, const adc_continuous_evt_data_t *edata, void *user_data)
+{
+  BaseType_t mustYield = pdFALSE;
+  /* Send notification to handler task */
+  vTaskNotifyGiveFromISR(adc_task_handle, &mustYield);
+  return (mustYield == pdTRUE);
+}
+
+/* Deinitializes ADC handles */
+static void adc_cleanup(void)
+{
+  ESP_LOGI(TAG, "Cleaning up ADC");
+  ESP_ERROR_CHECK(adc_continuous_stop(adc_handle));
+  ESP_ERROR_CHECK(adc_continuous_deinit(adc_handle));
+  ESP_ERROR_CHECK(adc_cali_delete_scheme_curve_fitting(adc_cali_handle));
+}
+
 /* Initializes calibration driver of internal 12bit ADC */
 static void adc_cali_init(void)
 {
   ESP_LOGI(TAG, "Initializing ADC calibration driver");
-  adc_cali_handle_t cali_handle;
   /* Create and apply calibration driver configuration */
   adc_cali_curve_fitting_config_t cali_config = {
     .unit_id = ADC_UNIT_1,
     .atten = ADC_ATTEN_DB_0,
     .bitwidth = ADC_BITWIDTH_DEFAULT
   };
-  ESP_ERROR_CHECK(adc_cali_create_scheme_curve_fitting(&cali_config, &cali_handle));
+  ESP_ERROR_CHECK(adc_cali_create_scheme_curve_fitting(&cali_config, &adc_cali_handle));
 }
 
 /* Initializes internal 12bit ADC */
-static void adc_init(void)
+static void adc_cont_init(void)
 {
-  /* Initialize calibration driver */
-  adc_cali_init();
-
   ESP_LOGI(TAG, "Initializing ADC continuous mode driver");
 
   /* Create continuous mode driver handle */
-  adc_continuous_handle_t adc_handle = NULL;
   adc_continuous_handle_cfg_t adc_handle_config = {
     .max_store_buf_size = 1024,
-    .conv_frame_size = 100
+    .conv_frame_size = ADC_READ_LEN
   };
   ESP_ERROR_CHECK(adc_continuous_new_handle(&adc_handle_config, &adc_handle));
 
@@ -67,10 +92,48 @@ static void adc_init(void)
   }
   adc_config.adc_pattern = adc_pattern;
   ESP_ERROR_CHECK(adc_continuous_config(adc_handle, & adc_config));
+
+  /* Configure callbacks */
+  adc_continuous_evt_cbs_t cbs = {
+    .on_conv_done = adc_conv_cb
+  };
+  ESP_ERROR_CHECK(adc_continuous_register_event_callbacks(adc_handle, &cbs, NULL));
 }
 
 void app_main(void)
 {
   /* Initialize internal ADC */
-  adc_init();
+  /* Initialize calibration driver */
+  adc_cali_init();
+  /* Initialize continuous driver */
+  adc_cont_init();
+  /* Start the continuous driver */
+  adc_task_handle = xTaskGetCurrentTaskHandle();
+  ESP_ERROR_CHECK(adc_continuous_start(adc_handle));
+
+  esp_err_t adc_ret;
+  uint32_t ret_num = 0;
+  uint8_t result[ADC_READ_LEN] = {0};
+
+  while (1) {
+    /* Perform a read */
+    adc_ret = adc_continuous_read(adc_handle, result, ADC_READ_LEN, &ret_num, 0);
+    if (adc_ret == ESP_OK) {
+      for (int i = 0; i < ret_num; i+= SOC_ADC_DIGI_RESULT_BYTES) {
+        /* Grab the data and channel number */
+        adc_digi_output_data_t *p_data = (void*)&result[i];
+        uint32_t chan = ((p_data)->type2.channel);
+        uint32_t data = ((p_data)->type2.data);
+        /* Check channel number to see if data is bogus */
+        if (chan < SOC_ADC_CHANNEL_NUM(ADC_UNIT_1)) {
+          ESP_LOGI("adc", "ADC_1_%"PRIu32" value: %"PRIx32, chan, data);
+        } else {
+          ESP_LOGW("adc", "Invalid data from ADC_1_%"PRIu32, chan);
+        }
+      }
+    }
+  }
+
+  /* Cleanup ADC */
+  adc_cleanup();
 }