Hi folks.
As users / debuggers of the ZSNES emu, some of you may be able to shed some light on a subject which has always interested me, that is NES compatibility on the Super Famicom. I have been informed that the Super Famicom / SNES has a pin out on both the 65sc816 CPU and PPU named 'HVC Mode' which is held at either +5 or 0 volts. Apparently this pin is permenantly disabled on all SNES models. I was therfore wondering (speculating) if it may be possible to enable this pinout and unearth some form of NES compatibility mode on the Super Famicom. I am also aware that 8 - bit add ons such as the Tri - Star Adaptor merley use the SNES for power and picture out purposes and achieve their emulation of the NES via in built (and illegal) NES hardware chips, which makes me think that NES compatibility was never actually achieved when the SNES was being designed.
Yep, its a nerdy post, but can anyone shed some info?
Regards,
Andrew Laggan
Super Famicom / SNES CPU/PPU 'HVC' Mode?
Moderator: ZSNES Mods
The picture processing units (PPUs) and sound processing unit (the SPC700) of the SNES are massively different from the equivalent hardware in the NES. There is no real compatibility between them, and games made for the NES will not run on the SNES even if you can successfully get the 65816 into emulation mode. [Nevermind the fact that emulation mode doesn't function precisely like the 6502.]