Effect list

Effect Description
0xy Arpeggio, x = second note, y = third note
1xx Pitch slide up, xx = speed (00 to disable)
2xx Pitch slide down, xx = speed (00 to disable)
3xx Automatic portamento, slides to new notes xx = speed (00 to disable)
4xy Vibrato effect, x = speed (0 to disable), y = depth
7xy Tremolo effect, x = speed (0 to disable), y = depth
Axy Volume slide, A0x = slide down, Ax0 = slide up
Bxx Jump to frame xx
Cxx Halt, stopping the song (xx doesn't do anything)
Dxx Skip to next frame and start at row xx
Exx Volume setting. Obsolete, use the volume colum instead.
Fxx Speed/tempo, sets the speed when xx is between 01 - 1F, and tempo when xx is between 20 - FF
Gxx Note delay, delay before the current row is triggered, xx = frames to wait
Hxy Hardware sweep up, triggers a hardware sweep up (only available on  2A03 squares) x = period (0 - 7), y = shift (1 - 7)
Ixy Hardware sweep down, triggers a hardware sweep down (only avaliable on 2A03 squares), x = period (0 - 7), y = shift (1 - 7)
Pxx Fine pitch, fine pitch offset setting, xx = offset (80 is default)
Qxy Note slide up, x = speed, y = number of notes
Rxy Note slide down, x = speed, y = number of notes
Sxx Delayed note cut. Cuts note after xx number of frames.
Vxx Square duty / noise mode, sets the square duty and noise mode setting, xx = 00 - 03 for square and 00 - 01 for noise. xx = 00 - 07 for VRC6.

DPCM effects

Effect Description
W0x DPCM pitch (0 - F)
Xxx DPCM retrigger, xx = length in frames between retrigger.
Yxx DPCM sample offset, each step adds 64 bytes
Zxx DPCM delta counter, changes the delta counter directly (through a write to $4011), affects volume of noise and triangle.  xx is between 00 - 80

FDS effects

Effect Description
Hxx Modulation depth (0 - 3F)
Ixx Modulation speed, high part (0 - F)
Jxx Modulation speed, low part (0 - FF)