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Support EWRAM wait state configuration through GBA register 4000800h #1276

HorstBaerbel opened this issue Jan 23, 2019 · 1 comment
severity:enhancement Feature requests


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HorstBaerbel commented Jan 23, 2019

The GBA (Regular + SP, NOT GBA Micro or DS) support EWRAM wait state control through "undocumented" register 4000800h (see GBATek). Support would be nice. Atm mGBA reports:

[GAME ERROR] GBA I/O: Write to unused I/O register: 800
[GAME ERROR] GBA I/O: Write to unused I/O register: 802


#define REG_WAITEWRAM (*(volatile uint32_t *)(REG_BASE + 0x0800))
// set undocumented register for EWRAM waitstates
// sets EWRAM wait states to 2/2/4 vs. 3/3/6 (default 0x0D000020)
REG_WAITEWRAM = 0x0E000020;
@endrift endrift added the severity:nice to have Low priority feature requests label Jan 24, 2019
@endrift endrift added this to the mGBA 1.1.0 milestone Jan 24, 2019
@endrift endrift added severity:enhancement Feature requests and removed severity:nice to have Low priority feature requests labels May 3, 2021
@endrift endrift modified the milestones: mGBA 1.1.0, mGBA 0.10.0 May 3, 2021
@endrift endrift closed this as completed in f9e03e7 Jun 7, 2022
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endrift commented Jun 7, 2022

I haven't added support for remapping/disabling EWRAM via the low bits yet, but this takes care of the easier stuff.

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