Power down OLED before deep sleep

include/display_ui.h

@@ -12,6 +12,7 @@ void display_set_last_meter(const MeterData &data);
 void display_set_last_read(bool ok, uint32_t ts_utc);
 void display_set_last_tx(bool ok, uint32_t ts_utc);
 void display_set_receiver_status(bool ap_mode, const char *ssid, bool mqtt_ok);
+void display_power_down();
 void display_tick();
 #ifdef ENABLE_TEST_MODE
 void display_set_test_code(const char *code);

src/display_ui.cpp

@@ -50,6 +50,17 @@ static void oled_set_power(bool on) {
   }
 }
 
+void display_power_down() {
+  if (!g_display_ready) {
+    return;
+  }
+  display.clearDisplay();
+  display.display();
+  oled_set_power(false);
+  g_oled_on = false;
+  g_last_oled_on = false;
+}
+
 void display_init() {
   pinMode(PIN_OLED_CTRL, INPUT_PULLDOWN);
   Wire.begin(PIN_OLED_SDA, PIN_OLED_SCL);

src/main.cpp

@@ -121,6 +121,7 @@ static void sender_cycle() {
   }
 
   delay(50);
+  display_power_down();
   lora_sleep();
   go_to_deep_sleep(SENDER_WAKE_INTERVAL_SEC);
 }