The arduino R3 pinout includes an IORef pin which will be 5v on a 5v arduino but 3.3v on a 3.3v arduino. Any IC’s on the shield should run at IORef. Report comment. Reply. F says: ...

Arduino enthusiasts, ... (a 2.4GHz RF transceiver, RF synthesiser, ... an LCD header, and standard Arduino pinouts to add whatever else your project desires. ...

CGA monitors may not be an amazing technological advance these days, but they can generally be found very cheaply. Additionally, they have a DB-9 connector and work off of TTL ranges (0-5VDC) makin… ...