Author Topic: Is it physically impossible to emulate the Super Gameboy on the SD2SNES?  (Read 6610 times)

0 Members and 2 Guests are viewing this topic.

Offline bluefoxicy

  • Newbie
  • *
  • Posts: 9
  • Karma: +0/-0
    • View Profile
Quote from: ikari_01
OTOH Super Gameboy might not be too far out of reach
as it already works in "real life" through the cartridge bus.
There is hope  ::) ::)

Considering the DSP-1 is a 10MHz 65c816 (yes, it's more powerful than the SNES main core itself) and the Gameboy Color is an 8.38MHz Z80, it's logically doable.  Mind you, the SD2SNES Pro is a Cyclone IV now; it's actually powerful enough to implement a hardware SNES.

Best approach would be to load the sprites destined for the Gameboy Color PPU into the SNES PPU, essentially hardware virtualizing the PPU rather than reimplementing and shuffling video.  You can do the same with the NES and Genesis if you really have that kind of programmer time; Gameboy Advance displays too many colors.

Offline the_randomizer

  • Full Member
  • ***
  • Posts: 164
  • Karma: +6/-0
    • View Profile
Why not the Super Game Boy 2? It's much better and actually has the proper timing, audio doesn't sound weird.

Offline nuu

  • Hero Member
  • *****
  • Posts: 1169
  • Karma: +56/-2
    • View Profile
I think the Super Game Boy is discussed in a general sense. If the SGB can be done, there is not much left to do for it to become an SGB2. Mainly the link port.

Offline Galron

  • Hero Member
  • *****
  • Posts: 599
  • Karma: +14/-0
    • View Profile
Also the whole timing issue can be fixed on a gbav1.

Offline nuu

  • Hero Member
  • *****
  • Posts: 1169
  • Karma: +56/-2
    • View Profile
Yes by adding a clock crystal that matches the Game Boy's. A link port can also be added.

Offline D2DEZEL

  • Newbie
  • *
  • Posts: 12
  • Karma: +0/-0
    • View Profile

Offline Gumball

  • Gumball Bunny
  • Full Member
  • ***
  • Posts: 158
  • Karma: +18/-0
  • Heavy Metal Rabbit
    • View Profile
http://helmet.kafuka.org/bboard/thread.php?id=178
I checked the link. What exactly does this mean? I only saw stuff related to BSNES. Does super gameboy work on the sd2snes now? or what.
All I wanna do is shred.

Offline Relikk

  • Sr. Member
  • ****
  • Posts: 277
  • Karma: +24/-8
    • View Profile
http://helmet.kafuka.org/bboard/thread.php?id=178
I checked the link. What exactly does this mean? I only saw stuff related to BSNES. Does super gameboy work on the sd2snes now? or what.

MSU1 type capability for Game Boy games.

Offline bluefoxicy

  • Newbie
  • *
  • Posts: 9
  • Karma: +0/-0
    • View Profile
Yes by adding a clock crystal that matches the Game Boy's. A link port can also be added.

Cyclone IV handbook says the EP4CE15E17C8N has 15,048 LEs, 594 Kbit embedded memory, 66 18x18 embedded multipliers, 4 general-purpose PLLs, 20 global clock networks, 8 user I/O banks, and 343 maximum user I/Os in the EP4CE15 series but 256 pins on this version.  As a 1.2V version (not low-power), it has a top clock speed of 166MHz; timing issues will apply, but the Gameboy is 4.194304MHz, and the GBC 8.388608MHz (twice GB).

The FPGA allows M, N, and C counters from 1 to 512.  The PLL multiplies the clock by M/(N*post-scale counter).  I see an A510N, which is a 32.768MHz oscillator.  For GBC, you'd need to multiply by 1/0.256, or 1000/256, so use 125/32.  For Gameboy, use 125/64.  Divide these by 2 for the PPU clock and 4 for the CPU clock (if you need PLLs, just produce the PPU clock in the first place, and divide it by 2 for the CPU clock).  Gameboy Advance clock is twice the GBC clock, but it uses a superscalar ARM processor and implementing that is difficult (and might cause timing issues, requiring slower clock speeds, although the FPGA can probably handle it), plus the FPGA may not have enough LEs.

SD2SNES also has a USB port, so you just need a USB-to-link-cable.

SD2SNES is open-source, so maybe start a kickstarter to pay someone to implement all this stuff.  Should work on SD2SNES Pro but it's going to be as much of a lift as creating an FPGA Gameboy Color.