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Undocumented CGB Registers

Optix edited this page Jan 30, 2021 · 1 revision

Metadata

Source File: /src/tests/undoc_regs.asm
Compatible with: CGB, AGB/AGS

Description

This test verifies the initial values and the behavior of "undocumented" registers $FF72-$FF75.

Error Messages

  • Invalid initial $FF7X - Reading from the register $FF7X (where X can be any value between 2 and 5) did not return the correct initial value
  • Read-only $FF7X - Writing to the register $FF7X (where X can be any value between 2 and 5) has no effect
  • Incorrect writeable bits on $FF75 - Any of the bits 7, 3, 2, 1 or 0 are affected by writing to the register $FF75

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