Revision 1 CPU DMA crash: Difference between revisions

Latest revision as of 19:40, 9 August 2023

Little is known about why the CPU revision 1 DMA crash happens. In 2015, Ramsis wrote a test rom to trigger it. ^[2]

page 2-25-1 of Book I of the official Super Nintendo development manual, the ICE mentioned likely stands for "In-Circuit Emulator"
https://forums.nesdev.org/viewtopic.php?t=13280

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-Little is known and the '''CPU revision 1 DMA crash'''.  In 2015, Ramsis wrote a test rom to trigger it.
+Little is known about why the '''CPU revision 1 DMA crash''' happens.  In 2015, Ramsis wrote a test rom to trigger it. <sup>[2]</sup>
+=== Trigger ===
+* kicking of an HDMA at about the same time that a [[General Purpose DMA]] finishes
+=== Symptoms ===
+* Sometimes the [[5A22]] will crash
+* Sometimes the [[HDMA]] will not happen correctly
+=== Workarounds ===
+* Use GPDMA only during [[vblank]]
+* Make sure HDMA starts in the middle of a GPDMA data transfer
+* Avoid HDMA
+* Adjust the time at which GPDMA begins
+* Decrease the number of bytes transferred during GPDMA
 === See Also ===
-* https://archive.org/details/SNESDevManual/book1/page/n111
+* [[Revision 1 PPU1 Time Over Bug]]
 === References ===
-* https://forums.nesdev.org/viewtopic.php?t=13280
+# [https://archive.org/details/SNESDevManual/book1/page/n111 page 2-25-1 of Book I] of the official Super Nintendo development manual, the ICE mentioned likely stands for "[https://www.microcontrollertips.com/faq-what-is-ice/# In-Circuit Emulator]"
+# https://forums.nesdev.org/viewtopic.php?t=13280
 [[Category:SNES Hardware]]