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Work RAM: Difference between revisions
From SnesLab
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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]]. <sup>[2]</sup> But, Nintendo still recommendeds checking to make sure the contents are correct after a reset. <sup>[5]</sup> | 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. | ||
[[Category:SNES Hardware]] | [[Category:SNES Hardware]] | ||
Revision as of 12:07, 18 December 2023
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
- https://problemkaputt.de/fullsnes.htm#snesmemoryworkramaccess
- https://problemkaputt.de/fullsnes.htm#snescontrollersotherinputs
- page 1 of Book II, "Super NES Parts List" in the official Nintendo development manual
- page 2-22-1 of Book II, lbid
- caution #11: page 2-24-3 of Book I