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Work RAM: Difference between revisions

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'''WRAM''' (Work RAM) serves as the SNES' main memory.  It is 128K x 8 bits (131,072 bytes) in size.  It has part number 21326. [3]
[[File:wram schematic.png|thumb|The WRAM chip is straddling regions C1 and D1 in the [[jwdonal schematic]]]]
 
'''WRAM''' (Work RAM) serves as the SNES' main memory.  It is 128K x 8 bits (131,072 bytes) in size, which is exactly two [[banks]].  It has part number 21326. <sup>[3]</sup>


Even though WRAM has both [[Address Bus A]] and [[Address Bus B]] connected to it, the chip can only pay attention to one at a time, so WRAM-to-WRAM [[DMA]] isn't possible.
Even though WRAM has both [[Address Bus A]] and [[Address Bus B]] connected to it, the chip can only pay attention to one at a time, so WRAM-to-WRAM [[DMA]] isn't possible.


WRAM is left intact by a [[Reset]]. [2]
WRAM is left intact by a [[Reset]]. <sup>[2]</sup>  But, Nintendo still recommendeds checking to make sure the contents are correct after a reset.  <sup>[5]</sup>  WRAM is DRAM and as such must be refreshed.
 
[[File:wram schematic.png|thumb|The WRAM chip is straddling regions C1 and D1 in the jwdonal schematic]]


[[Category:SNES Hardware]]
[[Category:SNES Hardware]]
[[Category:Integrated Circuits]]
[[Category:Integrated Circuits]]
[[Category:ICs with unconnected pins]]
[[Category:ICs with unconnected pins]]
[[Category:Address Spaces]]
=== See Also ===
* [[ARAM]]
* [[VRAM]]
* [[OAM]]


=== References ===
=== References ===
* [1] https://problemkaputt.de/fullsnes.htm#snesmemoryworkramaccess
# https://problemkaputt.de/fullsnes.htm#snesmemoryworkramaccess
* [2] https://problemkaputt.de/fullsnes.htm#snescontrollersotherinputs
# https://problemkaputt.de/fullsnes.htm#snescontrollersotherinputs
* page 1 of Book II, "Super NES Parts List" in the official Nintendo development manual
# [https://archive.org/details/SNESDevManual/book2/page/n404 page 1 of Book II], "Super NES Parts List" in the official Nintendo development manual
* https://archive.org/details/SNESDevManual/book1/page/n97
# paragraph 22.3 on [https://archive.org/details/SNESDevManual/book1/page/n97 page 2-22-1 of Book I], lbid
# caution #11: [https://archive.org/details/SNESDevManual/book1/page/n105 page 2-24-3 of Book I]

Latest revision as of 01:55, 12 August 2024

The WRAM chip is straddling regions C1 and D1 in the jwdonal schematic

WRAM (Work RAM) serves as the SNES' main memory. It is 128K x 8 bits (131,072 bytes) in size, which is exactly two banks. It has part number 21326. [3]

Even though WRAM has both Address Bus A and Address Bus B connected to it, the chip can only pay attention to one at a time, so WRAM-to-WRAM DMA isn't possible.

WRAM is left intact by a Reset. [2] But, Nintendo still recommendeds checking to make sure the contents are correct after a reset. [5] WRAM is DRAM and as such must be refreshed.

See Also

References

  1. https://problemkaputt.de/fullsnes.htm#snesmemoryworkramaccess
  2. https://problemkaputt.de/fullsnes.htm#snescontrollersotherinputs
  3. page 1 of Book II, "Super NES Parts List" in the official Nintendo development manual
  4. paragraph 22.3 on page 2-22-1 of Book I, lbid
  5. caution #11: page 2-24-3 of Book I