GM radio codes

Is there a way of protecting chevrolet radio memory code while changing the battery out. eg. 12 volt, 1 or 2 amp charger on the cables as you remove them from battery. I don't have my radio code but the radio still works, is there a button procedure I can follow to have a working radio display its code? Thanks for any help I'm sure this will help many others too.

The easiest way to keep power to the various memories while replacing a battery is with a set of those cheapie jumper cables that plug into the cigarette lighter. NOT POWER OUTLET (if equipped). The power outlet is "HOT" only when the ignition is "ON". Be sure the cigarette lighter outlets are "HOT" at all times on both vehicles. Connect the two vehicles together and replace your battery.