We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS
VRAM: Difference between revisions
From SnesLab
(chips A & B named in schematic) |
(→References: hid archive URL) |
||
| (10 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
[[File:vram chip.png|thumb|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. | 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. | |||
[[Category:SNES Hardware]] | [[Category:SNES Hardware]] | ||
[[Category:Integrated Circuits]] | [[Category:Integrated Circuits]] | ||
[[Category:Video]] | [[Category:Video]] | ||
[[Category:Address Spaces]] | |||
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.
See Also
References
- Appendix A-1 of the official Super Nintendo development manual
- paragraph 22.4 on page 2-22-1 of Book I, lbid.