add deep sleep mode

esp32_readout/display.cpp

@@ -35,3 +35,8 @@ void Display::print_weight(double val) {
   this->_display->printf("%.2f g", val);
   this->_display->refresh();
 }
+
+void Display::clear() {
+  this->_display->clearDisplay();
+  this->_display->refresh();
+}

esp32_readout/display.h

@@ -20,6 +20,7 @@
       void setup();
       void print(const char* text);
       void print_weight(double weight);
+      void clear();
   };
 
 #endif

esp32_readout/env.h

@@ -1,5 +1,8 @@
 #ifndef ENV
   #define ENV
+  #include <Arduino.h>
+  #include "driver/rtc_io.h"
+
   #include <BLEDevice.h>
   #include <BLEUtils.h>
   #include <BLEScan.h>
@@ -9,6 +12,11 @@
   #include <Adafruit_GFX.h>
   #include <Fonts/FreeSans9pt7b.h>
 
+  /********************* General ****************************/
+  #define BUTTON_PIN_BITMASK(GPIO) (1ULL << GPIO)
+  #define WAKEUP_GPIO              GPIO_NUM_1
+  #define SLEEP_GPIO               1
+
   /********************* NAU7802 ****************************/
 
   #define LDO NAU7802_3V3

esp32_readout/esp32_readout.ino

@@ -5,6 +5,7 @@ Display display;
 Adafruit_NAU7802 nau;
 unsigned long _millis = 0;
 int32_t val = 0;
+bool goToSleep = False;
 #if BLE
   BLEServer *pServer = NULL;
   BLECharacteristic *millisCharacteristic = NULL;
@@ -26,10 +27,42 @@ int32_t val = 0;
   };
 #endif
 
+void print_wakeup_reason() {
+  esp_sleep_wakeup_cause_t wakeup_reason;
+
+  wakeup_reason = esp_sleep_get_wakeup_cause();
+
+  switch (wakeup_reason) {
+    case ESP_SLEEP_WAKEUP_EXT0:     Serial.println("Wakeup caused by external signal using RTC_IO"); break;
+    case ESP_SLEEP_WAKEUP_EXT1:     Serial.println("Wakeup caused by external signal using RTC_CNTL"); break;
+    case ESP_SLEEP_WAKEUP_TIMER:    Serial.println("Wakeup caused by timer"); break;
+    case ESP_SLEEP_WAKEUP_TOUCHPAD: Serial.println("Wakeup caused by touchpad"); break;
+    case ESP_SLEEP_WAKEUP_ULP:      Serial.println("Wakeup caused by ULP program"); break;
+    default:                        Serial.printf("Wakeup was not caused by deep sleep: %d\n", wakeup_reason); break;
+  }
+}
+
+void IRAM_ATTR startSleep() {
+  display.clear();
+
+  esp_sleep_enable_ext0_wakeup(WAKEUP_GPIO, 1);
+
+  rtc_gpio_pullup_dis(WAKEUP_GPIO);
+  rtc_gpio_pulldown_en(WAKEUP_GPIO);
+
+  esp_deep_sleep_start();
+}
+
 void setup() {
   Serial.begin(115200);
   display.setup();
 
+  print_wakeup_reason();
+
+  /**** setup sleep interrupt ******/
+  pinMode(SLEEP_GPIO, INPUT);
+  attachInterrupt(digitalPinToInterrupt(SLEEP_GPIO), startSleep, FALLING);
+
   if (! nau.begin()) {
     Serial.println("Failed to find NAU7802");
     while (1) delay(10);  // Don't proceed.