http://wiki.nesdev.com/w/index.php/APU_Length_Counter
2. I followed the APU Sweep page and completely missed the point that
means the reload flag will be set periodically. I suggest mentioning this fact in the main text below.A NES APU sweep unit can be made to periodically adjust a pulse channel's period up or down.
http://wiki.nesdev.com/w/index.php/APU_Sweep
3. Add frame counter to the flow charts. Having 1 starting point in a flow chart makes it easier to follow.
http://wiki.nesdev.com/w/index.php/APU_Pulse
http://wiki.nesdev.com/w/index.php/APU_Triangle
http://wiki.nesdev.com/w/index.php/APU_Noise
http://wiki.nesdev.com/w/index.php/APU_DMC
Thanks.