CGRAM: Difference between revisions

Latest revision as of 04:42, 12 August 2024

CGRAM (Color Generator^[2] RAM) is a 512 byte buffer where palettes are stored for indirect color. The SNES uses 15-bit color here. It is word (not byte) addressed. For each of the 256 color entries:

bits 0 to 4 are the red intensity
bits 5 to 9 are the green intensity
bits 10 to 14 are the blue intensity
bit 15 is unused - reading it returns S-PPU2 open bus

In all background modes, sprites use the second half of CGRAM (addresses 80h to FFh).

When using CGRAM, color entries can be one of 32,768 colors from the master palette.

Direct Color is a technique that does not use CGRAM.

References

Appendix A-17 of the official Super Nintendo development manual on CG-RAM
https://problemkaputt.de/fullsnes.htm#snesmemorycgramaccesspalettememory

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-'''CGRAM''' is where palettes are stored.
+'''CGRAM''' (Color Generator<sup>[2]</sup> RAM) is a 512 byte buffer where palettes are stored for [[indirect color]].  The SNES uses 15-bit color here.  It is word (not byte) addressed.  For each of the 256 color entries:
+* bits 0 to 4 are the red intensity
+* bits 5 to 9 are the green intensity
+* bits 10 to 14 are the blue intensity
+* bit 15 is unused - reading it returns [[S-PPU2]] [[open bus]]
+In all [[background modes]], sprites use the second half of CGRAM (addresses 80h to FFh).
+When using CGRAM, color entries can be one of 32,768 colors from the master palette.
+[[Direct Color]] is a technique that does not use CGRAM.
+=== See Also ===
+* [[OAM]]
+* [[VRAM]]
+* [[PPU]]
+* [[The Infamous Bit-Of-Confusion]]
+=== References ===
+# [https://archive.org/details/SNESDevManual/book1/page/n211 Appendix A-17] of the official Super Nintendo development manual on CG-RAM
+# https://problemkaputt.de/fullsnes.htm#snesmemorycgramaccesspalettememory
 [[Category:Video]]
+[[Category:Address Spaces]]
+[[Category:Buffers]]