CODEWITHSUNDEEP
emulationgameboy
DNg
DNg

Reputation: 452

What are the differences between the Game Boy and the Game Boy Color in terms of emulation?

I'm writing an emulator for the game boy color (for fun). I've found tonnes of resources and references for the original game boy's hardware, namely Imran Nazar's tutorial (http://imrannazar.com/GameBoy-Emulation-in-JavaScript) and Zak's Book (Z80 instruction reference). As well I've been looking at some open source emulators to fill in the blanks.

One thing I can't figure out or find any resources on are GBC' memory layout and its gpu. GBC has 3x as much memory as the game boy and the LCD display supports 15bit color as opposed to 2bit. So there are definitely things that need to be accounted for.

Any help at all would be appreciated. :)

Upvotes: 7

Views: 2623

Answers (1)

TechyTommy
TechyTommy

Reputation: 13

  • The CGB (Game Boy Color) can run at double the speed that the DMG (original Game Boy) can. The DMG runs at 4.194304 megahertz, but the CGB can run at 8.388608 megahertz in double speed mode. So, you need your CGB emulator to run at double the speed that a DMG emulator does. How to figure that out? Bit 7 and 0 on register FF4D.
  • The CGB can do infrared communication. If the register FF56's byte 0, 1, and 6-7 is set, the CGB is doing infrared.
  • The CGB has 32 kibibytes of work RAM and 16 kibibytes of video RAM. On the DMG, there is 8 KiB of both.

Upvotes: 1

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