add 16B circular buffer for EEPROM

src/main.cpp

@@ -4,9 +4,13 @@
 #include <Wire.h>
 #include <RtcDS3231.h>
 #include <HX711.h>
+#include <EepromAT24C32.h>
 
 RtcDS3231<TwoWire> Rtc(Wire);
-HX711 scale;
+EepromAt24c32<TwoWire> RtcEeprom(Wire);HX711 scale;
+
+// void printDateTime(const RtcDateTime &dt);
+
 
 const int rtcPowerPin = 4;
 const int wakeUpPin = 7;
@@ -19,6 +23,10 @@ const int scalePowerPin = 19;
 const int secondsTillNextWakeup = 3;
 const long interval = 50;
 
+const int memTotal = 4096;
+const int pageSize = 16;
+const int pageCount = (memTotal / pageSize) - 1;
+
 void wake()
 {
     sleep_disable();
@@ -51,6 +59,7 @@ void setup()
     digitalWrite(scalePowerPin, HIGH);
 
     Rtc.Begin();
+    RtcEeprom.Begin();
 
     scale.begin(scaleDataPin, scaleSckPin);
     scale.set_scale(1000.f); // this value is obtained by calibrating the scale with known weights; see the README for details
@@ -118,12 +127,89 @@ void loop()
 
     RtcTemperature temp = Rtc.GetTemperature();
 
+    int lastA = -1;
+    int lastB = -1;
+
+    for (int i = 0; i <= pageCount; i++)
+    {
+        uint8_t x = RtcEeprom.GetMemory(i * pageSize);
+
+        if ((char)x == 'a')
+        {
+            lastA = i;
+        }
+
+        if ((char)x == 'b')
+        {
+            lastB = i;
+        }
+    }
+
+    int head = -1;
+    uint8_t next = 'c';
+
+    if (lastA == pageCount)
+    {
+        head = pageCount;
+        next = 'b';
+    }
+
+    if (lastB == pageCount)
+    {
+        head = pageCount;
+        next = 'a';
+    }
+
+    if (lastA > lastB)
+    {
+        head = lastB;
+        next = 'b';
+    }
+
+    if (lastB > lastA)
+    {
+        head = lastA;
+        next = 'a';
+    }
+
+    head = (head + 1) % pageCount;
+
+    // Serial.print("Last a: ");
+    // Serial.print(lastA);
+    // Serial.print(", Last b: ");
+    // Serial.print(lastB);
+    // Serial.print(", HEAD: ");
+    // Serial.print(head);
+    // Serial.print(", next: ");
+    // Serial.println((char)next);
+
     String buffer;
+    buffer += String((char)next);
     buffer += String(scale.get_units(1), 2);
     buffer += F(" kg, ");
     buffer += String(temp.AsFloatDegC(), 2);
     buffer += F(" °C");
-    Serial.println(buffer);
+    // Serial.println(buffer);
+    char data[pageSize];
+    buffer.toCharArray(data, pageSize);
+
+    RtcEeprom.SetMemory(head * pageSize, (const uint8_t *)data, sizeof(data) - 1);
+
+    for (int i = 0; i <= pageCount; i++)
+    {
+        uint8_t buff[pageSize + 1];
+        uint8_t gotten = RtcEeprom.GetMemory(i * pageSize, buff, pageSize);
+        Serial.print(i);
+        Serial.print(":\t");
+        Serial.print("data read (");
+        Serial.print(gotten);
+        Serial.print(") = \"");
+        for (uint8_t ch = 0; ch < gotten; ch++)
+        {
+            Serial.print((char)buff[ch]);
+        }
+        Serial.println("\"");
+    }
 
     Serial.flush();
     scale.power_down();
@@ -136,3 +222,6 @@ void loop()
 
     sleepNow();
 }
+
+
+/