Background

A Background is a layer of tiles, mapped and possibly scrolled, that appears behind the sprite layer. The SNES supports up to four simultaneous backgrounds, conventionally named:

• BG1
• BG2
• BG3
• BG4

throughout the official Super Nintendo development manual.

Mode	# of Layers Displayed	Layer	# of Tile Dots	# of Tile Colors	# of Palettes	# of Colors Per Layer	Function
0	max 4	BG1	8x8	4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG2	or	4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG3	16x16	4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG4		4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
1	max 3	BG1		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG2		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩
		BG3		4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩
2	max 2	BG1		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩	⑪
		BG2		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩	⑪
3	max 2	BG1		256	1	256	①	②	③		⑤	⑥	⑦	⑧	⑨	⑩
		BG2		16	8	128	①	②	③		⑤	⑥	⑦	⑧		⑩
4	max 2	BG1		256	1	256	①	②	③		⑤	⑥	⑦	⑧	⑨	⑩	⑪
		BG2		4	8	32	①	②	③		⑤	⑥	⑦	⑧		⑩	⑪
5	max 2	BG1		16	8	128	①	②	③		⑤		⑦	⑧				⑫
		BG2		4	8	32	①	②	③		⑤		⑦	⑧				⑫
6	1	BG1	16x8	16	8	128	①	②	③		⑤		⑦	⑧			⑪	⑫
7	1	BG1	8x8	256	1	256	①		③	④	⑤	⑥	⑦	⑧	⑨	⑩
EXT BG	1	BG1	8x8	128	1	128	①		③	④	⑤	⑥	⑦	⑧	⑨	⑩

Legend

1. Horizontal/Vertical Scrolling (each layer)
2. Horizontal/Vertical Flip (each tile)
3. Mosaic
4. Rotate, Enlarge, Shrink
5. Window Mask
6. Screen Addition/Subtraction
7. Fixed Color Addition/Subtraction
8. Color Window
9. Direct Color
10. Horizontal Pseudo 512
11. Offset Change Mode
12. Horizontal 512 Mode

Reference

• Appendix A-5 of Book I of the official Super Nintendo development manual