palette palette addresses outputs --------- ------------------------ BBBBBBBB PPPPPPPP RRRR GGGG BBBB 76543210 3210 3210 3210 FGBG 00000000 0000 0000 0000 0 00000001 1111 1111 1111 0 00000010 0000 0000 0000 0 00000011 1111 1111 1111 0 00000100 0000 0000 0000 1 00000101 1111 1111 1111 1 00000110 0000 0000 0000 1 00000111 1111 1111 1111 1 00001000 0000 0000 0000 0 00001001 1111 1111 1111 0 00001010 0000 0000 0000 0 00001011 1111 1111 1111 0 00001100 0000 0000 0000 1 00001101 1111 1111 1111 1 00001110 0000 0000 0000 1 00001111 1111 1111 1111 1

Since BP7 is low, the early pixel matters. Only care about BPO data, since it supplies the early data. Notice how the RGB output is all 119 only when BP0 is a 1, regardless of what the other BP's are doing. This is how you program the palette to ignore certain bitplanes. Did you see how FGBG is a 1 only when BP3 is a 1 regardless of other BPs?

10000000 0000 0000 0000 0 10000001 0000 0000 0000 0 10000010 1111 1111 1111 0 10000011 1111 1111 1111 0 10000100 0000 0000 0000 1 10000101 0000 0000 0000 1 10000110 1111 1111 1111 1 10000111 1111 1111 1111 1 10001000 0000 0000 0000 0 10001001 0000 0000 0000 0 10001010 1111 1111 1111 0 10001011 1111 1111 1111 0 10001100 0000 0000 0000 1 10001101 0000 0000 0000 1 10001110 1111 1111 1111 1 10001111 1111 1111 1111 1

Now BP7 is high. The late pixels are being output. Now, the RGB output is all l's only when BP1 (the late BP) is a 1, regardless of what the other BPs are doing. This is how to time multiplex between planes. Notice, now, that FGBG is still a 1 only if BP3 is a 1, regardless of the other Bps, like before. This makes FGBG immune to the mutiplexing. It also shows how you can mix modes on the same screen!

Note that BP4, BP5, and BP6 will be zero unless I specifically ask them to be set to 1 in the Bitplane Complement register. So if they are zero, I do not need to program the rest of the palette. But I can program the other parts of the palette, and use the bitplane complements for BP4, BP5, and BP6 to switch between sub-palettes!