ADC working

ADC funktioniert, aber ist gibt kein Pin an dem die aktuelle Batteriespannung ausgelesen werden kann. VMAIN ist eine konstant geregelte Spannung. Bei der TBS TANGO 2 sind es 6V.

Author: fabiankuffer

components/battery/CMakeLists.txt

@@ -2,4 +2,4 @@ set(srcs "battery.c")
 
 idf_component_register(SRCS "${srcs}"
                     INCLUDE_DIRS "include"
-                    REQUIRES bt ble)
+                    REQUIRES bt ble esp_adc)

components/battery/battery.c

@@ -4,8 +4,72 @@ static const char *tag_BAT = "SimLinkModule_BAT";
 
 uint8_t batteryPercentage = 0;
 
+static adc_oneshot_unit_handle_t adc_handle;
+static adc_cali_handle_t adc_cal_handle = NULL;
+static bool adc_calibrated = false;
+static int measurementCount = 0;
+static int sumVoltage = 0; //Voltage in mV
+
+
+//determine the esp ADC reference voltage which is around 1100 mV
+bool adc_calibration(adc_unit_t unit, adc_atten_t atten, adc_cali_handle_t *return_handle){
+    adc_cali_handle_t handle = NULL;
+    esp_err_t ret = ESP_FAIL;
+    bool returnValue = false;
+
+    adc_cali_line_fitting_config_t cal_config = {
+        .unit_id = unit,
+        .atten = atten,
+        .bitwidth = ADC_BITWIDTH_12,
+    };
+
+    //eFuse Vref represents the true ADC reference voltage. This value is measured and burned into eFuse BLOCK0 during factory calibration.
+    ret = adc_cali_create_scheme_line_fitting(&cal_config, &handle);
+    if (ret == ESP_OK) {
+        returnValue = true;
+    }
+
+    *return_handle = handle;
+    return returnValue;
+}
+
 void initBatteryRead(){
+    //adc init
+    adc_oneshot_unit_init_cfg_t init_config = {
+        .unit_id = ADC_UNIT_1,
+        .ulp_mode = ADC_ULP_MODE_DISABLE,
+    };
 
+    ESP_ERROR_CHECK(adc_oneshot_new_unit(&init_config, &adc_handle));
+
+    //adc configuration
+    //wenn .atten auf 0db Dämpfung gesetzt ist, ist der mögliche Wertebereich von 0 bis 1.1V
+    //bei .atten 12db wird der Wertebereich von 0 bis theoretisch 3.9V (3.55*1.1V) verwendet aber durch VDD auf 3.3V begrenzt 
+    //recommended range between 150 to 2450 mV at 12db
+    adc_oneshot_chan_cfg_t config = {
+        .bitwidth = ADC_BITWIDTH_12,
+        .atten = ADC_ATTEN_DB_11,
+    };
+    //esp32_technical_reference_manual_en.pdf page 629 for the pin/channel
+    ESP_ERROR_CHECK(adc_oneshot_config_channel(adc_handle, ADC_CHANNEL_4, &config));
+
+    //ADC calibration
+    adc_calibrated = adc_calibration(ADC_UNIT_1, ADC_ATTEN_DB_11, &adc_cal_handle);
+}
+
+//Voltage in mV
+int32_t getVoltage(){
+    int raw_val, voltage;
+    adc_oneshot_read(adc_handle, ADC_CHANNEL_4, &raw_val);
+    if(adc_calibrated){
+        //voltage in mV
+        adc_cali_raw_to_voltage(adc_cal_handle, raw_val, &voltage);
+    } else {
+        //rough value
+        voltage = (raw_val*3.3/4096)*1000;
+    }
+
+    return voltage;
 }
 
 void battery_Timer_Event(TimerHandle_t ev){
@@ -14,11 +78,34 @@ void battery_Timer_Event(TimerHandle_t ev){
     struct os_mbuf *om;
     int rc;
 
-    batteryPercentage = (batteryPercentage < 100) ? batteryPercentage+10 : 0;
+    getVoltage();
+    if(measurementCount < 10){
+        sumVoltage += getVoltage();
+        measurementCount++;
+    } else {
+        int avgVoltage = sumVoltage/10;
+        sumVoltage = 0;
+        measurementCount = 0;
+
+        //battery range between 3.4 and 4.2V
+        //r2/(r1+r2) = 0.755 akutell
+        //vmax_in = 4.2*0.755 = 3.171
+        //vmin_in = 3.8*0.755 = 2.869
+        //steps = (3171-2869)/100 = 302/100
+        int8_t newPercentage = 0;
+        if(avgVoltage > 2869) {
+            newPercentage = avgVoltage*302/100;
+        }
+
+        ESP_LOGI(tag_BAT, "%d", newPercentage);
 
-    if(notify_state_battery_status){
-        om = ble_hs_mbuf_from_flat(&batteryPercentage, sizeof(batteryPercentage));
-        //Deprecated. Should not be used. Use ble_gatts_notify_custom instead.
-        rc = ble_gattc_notify_custom(conn_handle, battery_status_handle, om);
+        if(newPercentage != batteryPercentage){
+            if(notify_state_battery_status){
+                om = ble_hs_mbuf_from_flat(&batteryPercentage, sizeof(batteryPercentage));
+                //Deprecated. Should not be used. Use ble_gatts_notify_custom instead.
+                rc = ble_gattc_notify_custom(conn_handle, battery_status_handle, om);
+            }
+            newPercentage = batteryPercentage;
+        }
     }
 }

components/battery/include/battery.h

@@ -6,6 +6,11 @@
 #include <stdint.h>
 #include "freertos/FreeRTOS.h"
 #include "freertos/timers.h"
+
+#include "esp_adc/adc_oneshot.h"
+#include "esp_adc/adc_cali.h"
+#include "esp_adc/adc_cali_scheme.h"
+
 #include "host/ble_gatt.h"
 
 #include "gatt.h"
@@ -15,5 +20,6 @@ extern uint8_t batteryPercentage;
 
 void initBatteryRead();
 void battery_Timer_Event(TimerHandle_t ev);
+bool adc_calibration(adc_unit_t unit, adc_atten_t atten, adc_cali_handle_t *out_handle);
 
 #endif

docs/todo

@@ -9,3 +9,5 @@
 - buttons hinzufügen
 - LEDs hinzufügen
 - Display output hinzufügen
+- freertos timer stürzt zu oft ab fehler beheben wie im forum steht
+- Verbindung zu ADC sollte eigentlich mit Transistor geschalten werden damit nicht dauerhat strom fließt zu maße über den Spannungsteiler, auch sollte ein kondensator noch hinzugefügt werden, damit rauschen vermindert wird.

main/main.c

@@ -41,8 +41,9 @@ void app_main(void)
     xTaskCreate(crsf_get_ChannelData_task, "crsf_task", 4096, NULL, 10, NULL);
 
     //timer to read battery percentage via ADC
-    //wert alle 10 sekunden auslesen
-    batteryTimerHandle = xTimerCreate("battery_timer", pdMS_TO_TICKS(10000), pdTRUE, (void *)0, battery_Timer_Event);
+    initBatteryRead();
+    //wert jede sekunde auslesen --> aus 10 messungen wird der mittelwert gebildet --> vermindern von rauschen
+    batteryTimerHandle = xTimerCreate("battery_timer", pdMS_TO_TICKS(1000), pdTRUE, (void *)0, battery_Timer_Event);
 
     //start the timer
     if (xTimerStart(batteryTimerHandle, 1000 / portTICK_PERIOD_MS ) != pdPASS) {