VRAM: Difference between revisions

Latest revision as of 19:07, 11 August 2024

VRAM chip B in region B2 of the jwdonal schematic (directly north of chip A)

There are two VRAM chips on the SNES motherboard, both connected to S-PPU1. They are both SRAM and each 32K x 8 bit (32,768 bytes) in size, for a total of 65,536 bytes (one bank).

VRAM is word (not byte) addressed, with one chip holding the low bytes of the 16-bit words, the other chip holds the high bytes.

The two chips can be referred to as "A" and "B", after the lines of the VRAM Data Bus VDA0~7 and VDB0~7.

VRAM is not connected to Address Bus A, so the 5A22 must access it through I/O ports.

References

Appendix A-1 of the official Super Nintendo development manual
paragraph 22.4 on page 2-22-1 of Book I, lbid.

@@ Line 1: / Line 1: @@
-There are two '''VRAM''' chips on the SNES motheboard, both connected to [[S-PPU1]].
+[[File:vram chip.png|thumb|VRAM chip B in region B2 of the [[jwdonal schematic]] (directly north of chip A)]]
-One chip holds the low bytes of the 16-bit words, the other chip holds the high bytes.
+There are two '''VRAM''' chips on the SNES motherboard, both connected to [[S-PPU1]].  They are both [[SRAM]] and each 32K x 8 bit (32,768 bytes) in size, for a total of 65,536 bytes (one [[bank]]).
+VRAM is word (not byte) addressed, with one chip holding the low bytes of the 16-bit words, the other chip holds the high bytes.
+The two chips can be referred to as "A" and "B", after the lines of the [[VRAM Data Bus]] VDA0~7 and VDB0~7.
+VRAM is not connected to [[Address Bus A]], so the [[5A22]] must access it through I/O ports.
+=== See Also ===
+* [[WRAM]]
+* [[ARAM]]
+=== References ===
+* [https://archive.org/details/SNESDevManual/book1/page/n195 Appendix A-1] of the official Super Nintendo development manual
+* paragraph 22.4 on [https://archive.org/details/SNESDevManual/book1/page/n97 page 2-22-1 of Book I], lbid.
-[[File:vram chip.png|thumb|upper VRAM chip in region B2 of the jwdonal schematic]]
 [[Category:SNES Hardware]]
 [[Category:Integrated Circuits]]
 [[Category:Video]]
+[[Category:Address Spaces]]