1 files changed, 52 insertions, 0 deletions
diff --git a/libraries/EEPROM/examples/eeprom_update/eeprom_update.ino b/libraries/EEPROM/examples/eeprom_update/eeprom_update.ino
new file mode 100644
index 0000000..e0e18d8
--- /dev/null
+++ b/libraries/EEPROM/examples/eeprom_update/eeprom_update.ino
@@ -0,0 +1,52 @@
+/***
+   EEPROM Update method
+  
+   Stores values read from analog input 0 into the EEPROM.
+   These values will stay in the EEPROM when the board is
+   turned off and may be retrieved later by another sketch.
+  
+   If a value has not changed in the EEPROM, it is not overwritten
+   which would reduce the life span of the EEPROM unnecessarily.
+   
+   Released using MIT licence.
+ ***/
+
+#include <EEPROM.h>
+
+/** the current address in the EEPROM (i.e. which byte we're going to write to next) **/
+int addr = 0;
+
+void setup(){ /** EMpty setup **/ }
+
+void loop()
+{
+  /***
+    need to divide by 4 because analog inputs range from
+    0 to 1023 and each byte of the EEPROM can only hold a
+    value from 0 to 255.
+  ***/
+  int val = analogRead(0) / 4;
+
+  /***
+    Update the particular EEPROM cell.
+    these values will remain there when the board is
+    turned off.
+  ***/
+  EEPROM.update(addr, val);
+  
+  /***
+    The function EEPROM.update(addr, val) is equivalent to the following:
+  
+    if( EEPROM.read(addr) != val ){
+	  EEPROM.write(addr, val);
+    }
+  ***/
+  
+
+  /** advance to the next address.  there are 512 bytes in the EEPROM, so go back to 0 when we hit 512. **/
+  addr = addr + 1;
+  if (addr == 512)
+    addr = 0;
+
+  delay(100);
+}