Added wasRestored(), bumped version to 1.2.1

README.md

@@ -20,7 +20,9 @@ This library will emulate EEPROM in RTC RAM, which stays powered during deep sle
 
 ### Optional saving to NVS (flash)
 
-If you call `EEPROM.toNVS()`, a copy of your EEPROM data will be save to the key "eeprom" in NVS flash, exactly like when you would use the original `EEPROM.h`. Whenever the ESP32_RTC_EEPROM wakes up with an empty RTC RAM (which is detects by the presence of a magic word), it will try to see if there's a saved copy of the right size. If so, that is loaded. You can also manually revert to the last save by calling `EEPROM.fromNVS()`. 
+If you call `EEPROM.toNVS()`, a copy of your EEPROM data will be save to the key "eeprom" in NVS flash, exactly like when you would use the original `EEPROM.h`. Whenever the ESP32_RTC_EEPROM wakes up with an empty RTC RAM (which is detects by the presence of a magic word), it will try to see if there's a saved copy of the right size. If so, that is loaded. You can also manually revert to the last save by calling `EEPROM.fromNVS()`.
+
+The function `EEPROM.wasRestored()` will tell you whether or not the contents were automaticcaly restored from NVS in this boot cycle.
 
 ### Usage
 
@@ -32,6 +34,6 @@ If you call `EEPROM.toNVS()`, a copy of your EEPROM data will be save to the key
 
 ### Details
 
-* This library will always claim `EEPROM_SIZE` (set at 2048, change in the .h file) bytes of the RTC's RAM (it has 8k). You can set a lower number when calling `EEPROM.begin()`, but that number only  limits what your code can read/write, not the actual RAM used.
+* This library will always claim `EEPROM_SIZE` (set at 2048, change in the .h file) bytes of the RTC's RAM (it has 8k). You can set a lower number when calling `EEPROM.begin()`, but that number only  limits what your code can read/write (and how much is written to NVS flash every time when backing up), not the actual RTC RAM used.
 
 * Cannot repeat it often enough: **only useful in combination with the ESP's deep sleep, data in this fake EEPROM does not survive powercycling, resetting or reflashing** 

examples/deep_sleep_boot_count/deep_sleep_boot_count.ino

@@ -25,6 +25,11 @@ void setup() {
 
   // Print boot count
   Serial.println("Boot count: " + String(bootcount));
+
+  // See if this was restored from NVS
+  if (EEPROM.wasRestored()) {
+    Serial.println("(This value was restored from NVS, so we may have missed a few.)");
+  }
 
   // Write new value
   EEPROM.write(0, bootcount);

library.properties

@@ -1,5 +1,5 @@
 name=ESP32_RTC_EEPROM
-version=0.2.0
+version=0.2.1
 author=Rop Gonggrijp <[email protected]>
 maintainer=Rop Gonggrijp <[email protected]>
 sentence=EEPROM emulation that stores in RTC RAM. Survives deep sleep, but not reset or power loss. 

src/ESP32_RTC_EEPROM.cpp

@@ -4,7 +4,7 @@
              -ported by Paolo Becchi to Esp32 from esp8266 EEPROM
              -Modified by Elochukwu Ifediora <[email protected]>
              -Converted to nvs [email protected]
-             -Adapted for ESP32_RTC_EEPROM.cpp by Rop Gonggrijp
+             -Adapted for ESP32_RTC_EEPROM.cpp by Rop Gonggrijp <[email protected]>
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
@@ -31,6 +31,8 @@ uint8_t RTC_DATA_ATTR EEPROMClass::_data[EEPROM_SIZE] = { 0x23, 0x42, 0x23, 0x42
 
 size_t EEPROMClass::_size = EEPROM_SIZE;
 
+bool EEPROMClass::_restored = false;
+
 
 EEPROMClass::EEPROMClass(void)
 {
@@ -92,6 +94,10 @@ bool EEPROMClass::toNVS() {
   return true;
 }
 
+bool EEPROMClass::wasRestored() {
+  return _restored;
+}
+
 bool EEPROMClass::begin(size_t size) {
   if (!size || size > EEPROM_SIZE) {
     return false;
@@ -109,6 +115,7 @@ bool EEPROMClass::begin(size_t size) {
       *magic_word = 0;
     } else {
       log_w("RTC EEPROM contents recovered from NVS backup.");
+      _restored = true;
     }
   }
   return true;

src/ESP32_RTC_EEPROM.h

@@ -4,7 +4,7 @@
            -ported by Paolo Becchi to Esp32 from esp8266 EEPROM
            -Modified by Elochukwu Ifediora <[email protected]>
            -Converted to nvs [email protected]
-           -Adapted for ESP32_RTC_EEPROM.cpp by Rop Gonggrijp
+           -Adapted for ESP32_RTC_EEPROM.cpp by Rop Gonggrijp <[email protected]>
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
@@ -41,6 +41,7 @@ class EEPROMClass {
     static bool begin(size_t size);
     static bool fromNVS();
     static bool toNVS();
+    static bool wasRestored();
     static uint8_t read(int address);
     static void write(int address, uint8_t val);
     static uint16_t length();
@@ -108,6 +109,7 @@ class EEPROMClass {
   protected:
     static size_t _size;
     static uint8_t RTC_DATA_ATTR _data[EEPROM_SIZE];
+    static bool _restored;  
 };
 
 #if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_EEPROM)