I just got a working demo of a side project done. It is a very simple tb 303 style synth. The demo has a hard coded beat that you can turn off and on. You can program your own basslines although you can't save. You can download it for a PSP 1.5 from http://www.psprhythm.com/bassline.zip. My goal is to bring this into PSP Rhythm so you can have a bassline and drum machine/sampler to make music.
analog stick controls the filter cutoff and resonance, dpad selects steps and alters notes/decay/accent/slide. circle turns off and on the beat. triangle changes between a saw and a square waveform. X turns notes off and on (green is a "note tie"). Start - starts and stops the pattern.