* IRQ - used in scanline mode only for split screen (display of non-scrollable status bar). * PRG mode: $8000-$bfff = 16k switchable, $c000-$ffff: hardwired to last 16k bank (UNROM) Unfortunatelly "SMB 2 players" is based on VRC6 mapper, so I would need to make FPGA emulation of it, but that would be waste of resources because game utilizes only tine subset of mapper's capabilities.
Super Mario Bros 2 JPN a'ka SMB2J Lost Levels (mapper 40), entirely discrete: Pegasus 5 in 1 (a'ka The Golden 5 - Zlota Piatka, entirely discrete version and comparision with the original PCB using PAL: Gyruss (FDS port), this one made for testing the KS204 chip and confirm that the Metroid's KS204 is the same chip but wired differently:įamily Noraebang Karaoke, made mainly for testing the YM2413 chip Magic Kid GooGoo (mapper 190), using PAL just like the original cartridge:ģD block, made mainly for testing the PIC1654: Metal Force (mapper 156), entirely discrete: + can use pre-programmed DIP roms (cheaper and faster in soldering, no need to wait until CHR-RAM is pre-filled with content like in previous case)īut sometimes when I really have too much time or need to make a particular game, but I ran out of general-purpose programmable chips, I need to fit with what I have at the moment:
+ can be adjusted to any PCB and potentially support any mapper + it is 5V tolerant so no need of extra buffers They use smaller (both in terms of number of pins and amount of gates) EPM3064 FPLD, but Those PCB might look same for first view, but they are a little different because different address/data lines are driven into CPLD, depending on the mapper (it does not have enough pins to get full access to all CPU-A and CPU-D at once).
Or even more common mappers like MMC1 (this time with battery): Megami Tensei: Digital Devil Story (mapper 76):ĭevil's Town 1 FDS port (a'ka Castlevania 1):ĭevil's Town 2 FDS port (a'ka Castlevania 2): Punch Out (MMC2) with support for PPU address latch: Nazo no Murasamejou FDS with proper holes to fit into famicom shell:įire Emblem/Fire emblem gaiden (MMC4) with support for PPU address latch To overcome those drawbacks, I occasionally design a special PCB for a particular game, for example: does not fit into origial famicom shell quite expensive, because utilizes a lot of components (FPGA, 72256 buffers) can not mimic some fancy stuff like MMC2/MMC4, MMC5 because it does not have PPU address lines wired to FPGA nor dual port RAM + by replacing EPM240 with EPM570 even fully functional mapper 90 or even mix of two less complicated mappers (like MMC3+mapper 69) can be pre-programmed at once. + can mimic almost many mapper, with PRG-ROM/RAM, CHR-ROM/RAM or even both, battery Normally for that purpose I use my universal EPM240 based PCB that: Some background overview, skip that if you're lazy. I wanted to make a cartridge version of `Mario 2 Players hack` at ultimately low cost.
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