CPU Test Mode: Difference between revisions

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* Forum: [http://forums.nesdev.org/viewtopic.php?f=9&t=9197 Breaking NES apart (WARNING: traffic)]
* Forum: [http://forums.nesdev.org/viewtopic.php?f=9&t=9197 Breaking NES apart (WARNING: traffic)]
* Forum: [http://forums.nesdev.org/viewtopic.php?f=9&t=14421 Memory map and 2A03 register map]
* Forum: [http://forums.nesdev.org/viewtopic.php?f=9&t=14421 Memory map and 2A03 register map / 2A03 cutting-room floormetal]
* See: [[:File:Apu address.jpg]]
* See: [[:File:Apu address.jpg]]
* See: [[CPU pin out and signal description]]
* See: [[CPU pin out and signal description]]

Revision as of 18:26, 8 July 2016

Pin 30 of the 2A03 can be activated to enable a special test mode for the CPU. This activates a few registers in the range of $4018-401F.

Test mode activates registers for testing the APU at $4018-401A.

Visual inspection of the CPU indicates there was planned IRQ functionality from $401C-401F, but this is left unfinished and unusable.