add eeprom library explicitly

digistump-avr/libraries/EEPROM/examples/eeprom_read/eeprom_read.ino

@@ -0,0 +1,57 @@
+/*
+ * EEPROM Read
+ *
+ * Reads the value of each byte of the EEPROM and prints it
+ * to the computer.
+ * This example code is in the public domain.
+ */
+
+#include <EEPROM.h>
+
+// start reading from the first byte (address 0) of the EEPROM
+int address = 0;
+byte value;
+
+void setup()
+{
+  // initialize serial and wait for port to open:
+  Serial.begin(9600);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for Leonardo only
+  }
+}
+
+void loop()
+{
+  // read a byte from the current address of the EEPROM
+  value = EEPROM.read(address);
+
+  Serial.print(address);
+  Serial.print("\t");
+  Serial.print(value, DEC);
+  Serial.println();
+
+  /***
+    Advance to the next address, when at the end restart at the beginning.    
+    
+    Larger AVR processors have larger EEPROM sizes, E.g:
+    - Arduno Duemilanove: 512b EEPROM storage.
+    - Arduino Uno:        1kb EEPROM storage.
+    - Arduino Mega:       4kb EEPROM storage.
+    
+    Rather than hard-coding the length, you should use the pre-provided length function.
+    This will make your code portable to all AVR processors.    
+  ***/
+  address = address + 1;
+  if(address == EEPROM.length())
+    address = 0;
+    
+  /***
+    As the EEPROM sizes are powers of two, wrapping (preventing overflow) of an 
+    EEPROM address is also doable by a bitwise and of the length - 1.
+    
+    ++address &= EEPROM.length() - 1;
+  ***/
+
+  delay(500);
+}