Add code for demuxing 4 switch signals from adc pin

- create new files with code for demultiplexing the 4 switches from the
  one analog signal
- define lookup table with measurements done with the build pcb, test
  switches and esp32 breakout board
- add note do config that gpio used for digital in is now used for
  this multiplexer
- main.cpp: disable control task, run new handle function in a loop for
  testing

main/CMakeLists.txt

@@ -6,6 +6,7 @@ idf_component_register(
         "buzzer.cpp"
         "vfd.cpp"
         "display.cpp"
+        "switchesAnalog.cpp"
     INCLUDE_DIRS 
         "."
     )

main/config.hpp

@@ -28,7 +28,7 @@ extern "C" {
 #define GPIO_SW_RESET GPIO_NUM_25
 #define GPIO_SW_SET GPIO_NUM_33
 #define GPIO_SW_PRESET1 GPIO_NUM_32
-#define GPIO_SW_PRESET2 GPIO_NUM_34
+#define GPIO_SW_PRESET2 GPIO_NUM_32 //gpio 34 currently used fir testing switches-analog
 #define GPIO_SW_PRESET3 GPIO_NUM_39
 
 #define GPIO_POTI GPIO_NUM_36

main/main.cpp

@@ -14,6 +14,8 @@ extern "C"
 #include "control.hpp"
 #include "buzzer.hpp"
 
+#include "switchesAnalog.hpp"
+
 
 //=================================
 //=========== functions ===========
@@ -80,11 +82,16 @@ extern "C" void app_main()
     esp_log_level_set("buzzer", ESP_LOG_ERROR);
     esp_log_level_set("control", ESP_LOG_INFO);
 
-    //create task for controlling the machine
-    xTaskCreate(task_control, "task_control", configMINIMAL_STACK_SIZE * 3, NULL, 5, NULL);
-    //create task for handling the buzzer
-    xTaskCreate(&task_buzzer, "task_buzzer", 2048, NULL, 2, NULL);
+//    //create task for controlling the machine
+//    xTaskCreate(task_control, "task_control", configMINIMAL_STACK_SIZE * 3, NULL, 5, NULL);
+//    //create task for handling the buzzer
+//    xTaskCreate(&task_buzzer, "task_buzzer", 2048, NULL, 2, NULL);
 
     //beep at startup
     buzzer.beep(3, 70, 50);
+
+    while(1){
+        switchesAnalog_handle();
+        vTaskDelay(500 / portTICK_PERIOD_MS);
+    }
 }

main/switchesAnalog.cpp

@@ -0,0 +1,97 @@
+#include "switchesAnalog.hpp"
+
+#define CHECK_BIT(var,pos) (((var)>>(pos)) & 1) //TODO duplicate code: same macro already used in vfd.cpp
+
+
+
+//=============================
+//========= readAdc ===========
+//=============================
+//TODO add this to gpio library - used multiple times in this project
+//function for multisampling an anlog input
+int readAdc(adc1_channel_t adc_channel, bool inverted = false) {
+    //make multiple measurements
+    int adc_reading = 0;
+    for (int i = 0; i < 16; i++) {
+        adc_reading += adc1_get_raw(adc_channel);
+    }
+    adc_reading = adc_reading / 16;
+    //return original or inverted result
+    if (inverted) {
+        return 4095 - adc_reading;
+    } else {
+        return adc_reading;
+    }
+}
+
+
+
+
+
+//=====================
+//===== Variables =====
+//=====================
+static const char *TAG = "switches-analog"; //tag for logging
+int diffMin = 4095;
+int adcValue;
+int match_index = 0;
+
+//array that describes voltages for all combinations of the 4 inputs
+const int lookup_voltages[] = {
+    //ADC, S3 S2 S1 S0
+    4095, //0000
+    3642, //0001
+    3243, //0010
+    2887, //0011
+    2628, //0100
+    2413, //0101
+    2274, //0110
+    2112, //0111
+    1864, //1000
+    1748, //1001
+    1671, //1010
+    1579, //1011
+    1488, //1100
+    1418, //1101
+    1360, //1110
+    1294  //1111
+};
+
+
+
+
+//===========================
+//===== handle function =====
+//===========================
+void switchesAnalog_handle(){
+    //read current voltage
+    adcValue = readAdc(ADC_CHANNEL_BUTTONS);
+    ESP_LOGI(TAG, "voltage read: %d", adcValue);
+
+    //find closest match in lookup table
+    for (int i=0; i<16; i++){
+        int diff = fabs(adcValue - lookup_voltages[i]);
+        if (diff < diffMin){
+            diffMin = diff;
+            match_index = i;
+        }
+    }
+
+    //get bool values for each input from matched index
+    bool s0 = CHECK_BIT(match_index, 0);
+    bool s1 = CHECK_BIT(match_index, 1);
+    bool s2 = CHECK_BIT(match_index, 2);
+    bool s3 = CHECK_BIT(match_index, 3);
+    //bool s1 = ((match_index & 0b1000) == 0b1000);
+    //bool s2 = ((match_index & 0b0100) == 0b0100);
+    //bool s3 = ((match_index & 0b0010) == 0b0010);
+    //bool s4 = ((match_index & 0b0001) == 0b0001);
+
+
+    //log results
+    ESP_LOGI(TAG, "adcRead: %d, closest-match: %d, diff: %d, index: %d, switches: %d%d%d%d",
+            adcValue, lookup_voltages[match_index], diffMin, match_index, (int)s3, (int)s2, (int)s1, (int)s0);
+
+
+}
+

main/switchesAnalog.hpp

@@ -0,0 +1,20 @@
+#pragma once
+extern "C"
+{
+#include <stdio.h>
+#include <freertos/FreeRTOS.h>
+#include "esp_log.h"
+#include "driver/adc.h"
+#include <math.h>
+
+}
+
+#include "config.hpp"
+
+
+#define GPIO_BUTTONS GPIO_NUM_34
+#define ADC_CHANNEL_BUTTONS ADC1_CHANNEL_6 //gpio 34
+
+
+
+void switchesAnalog_handle();