During play, pause, hold R2 and R1 and press down 3 times then press cirlce 3 times.
When in the game press the start button then then hold R1 + R2 and press left, up, right, down, Square, Triangle, Circle, Ex
When at the main menu screen press and hold R2
then press left,right,down,up,square circle,X, and then Triangle.
If entered correctly you should hear a sound.