Here comes a joystick tester program by Art.

Quote from Art:

Hi Guys,
I thought the PSP scene was short on button tester type apps,
so here’s a program that will test the joystick angle.
It’s a little thing I was been playing with to test 2D rotation.
It doesn’t test magnitude (distance from the center or dead zone).
Art.

http://forums.qj.net/psp-development-forum/157617-joystick-angle-test.html