IRQ Templates and Best Practices?

[Lucradan]

UPDATE:

Well that worked. I removed the PPUMASK write that was at the end of the initialization code and put it at the end of the update code. In both positions it immediately followed a BIT wait, so I am not sure why the difference in position caused the problem. Now the left image is blank which works for me. I'd like to know why I was getting this error because I must not be understating something subtle about the timing and ordering of NMI, bulk writes to the PPU, and the enable/disable rendering.