SNES (Tag: donor)

Finding a donor cartridge

To create a reproduction game we will need to do something a lot of collectors hate the people doing reproductions for.
We need to take a genuine working game and 'destroy' it to place the game of our choice.
I personally don't have a real problem with it, I see it as replacing a lesser game with a better one.

The first step in finding a donor cartridge for the game you want to make is to study the new game.
Grab a rom file (I pick them from a GoodSNES set and use the good dumps, with an asterix behind it) and get the info from the game with a tool.
You can use SNES9x and choose "ROM Information" from the file menu, or use a tool like ucon64 (with frontend).

The info consists of these crucial parts:

  • ROM size
  • HiROM or LoROM
  • Save memory size and battery (either both or none)
  • Special Chips (Super FX, SA-1, SDD-1, etc)

Everything above has to be checked when selecting a donor for the new game.
All of these properties also come together in what is known as a PCB-ID, the code printed in gold letters on the print of a SNES game like SHVC-1A3M-30.

Components of the PCB-ID
The components of the PCB-ID have the following meaning:

SHVC: Default prefix, there are others but this first part of the PCB-ID can be ignored.
1A3M: The only relevant part of the PCB-ID, read on below about this component identifier.
30: This is the PCB revision number, irrelevant for selecting a donor.

Each character in the middle part explains about what components are on the pcb.

First digit:
The number of ROM chips that are on the pcb. Usually 1 or 2 (sometimes the letter B is used instead of the number 2).
Only thing you cannot see here that does matter is the number of pins of the ROM chip(s).
When there are 32 pins it is 8 MBit max, 36 pins allows up to 32 Mbit in size but that also depends on the decoder chip in the fourth digit.

Second digit:
This is the indicator for LoROM or HiROM, HiROM = J and LoROM = A.

Third digit:
Memory (SRAM) size of the pcb.
0 = No SRAM
1 = 16KBit / 2KB
3 = 64KBit / 8KB
5 = 256Kbit / 32KB

Fourth digit:
The decoder chip used.
B = '139 decoder supporting up to 16 MBit (if there are 36 pins for the ROM)
M = MAD-1 decoder supporting up to 32 MBit
N = No decoder (so 8 MBit ROM is the limit)

As you can see it takes the first and the fourth digit to see if your new game will fit on the pcb or not.
When the third digit indicates anything but 0 there is always a battery on the pcb.

When you've figured out what the PCB-ID(s) can be for the donor game you can for example look up what game uses what pcb using snescentral:
You're not guaranteed to get the pcb you want because some games had different pcb's in their lifecycle.

I hope this guide is useful for if you're looking for a donor cartridge.
For any questions you can always contact me.

Thanks alot to, among others, qwertymodo from the nesdev forums.

By Stefan Nicodem