MEG-03 - OSEPP MEGA 2560 R3 PLUS COMPATIBLE WITH ARDUINOOSEPP? Mega 2560 R3 Plus The OSEPP? Mega 2560 R3 Plus is the bigger brother to the OSEPP? Uno board with more flash memory more SRAM more EEPROM and more pins. This board is perfect for projects that require a lot of inputs outputs or that require more complex programs that cannot fit into the smaller memory of the ATmega328P. New in R3: Added SCL SDA pins next to AREF header Added IOREF pin to power header ? Plus? Features: Replaced USBB connector