GoKawiilApril 21, 2024
Inside the Super Nintendo cartridges
One of the remarkable characteristics of the Super Nintendo was the ability for game cartridges (cart) to pack more than instructions and assets into ROM chips. If we open and look at the PCBs, we can find inside things like the CIC copy protection chip, SRAM, and even "enhancement processors".
CIC
The copy-protection mechanism of the SNES is something I already dig into in my 10NES article. It works by having two chips talking in lockstep. One chip is in the console, the other in the cart. If the console CIC sees something it does not like, it resets every processor.
Not every SNES cart has a CIC. Unsanctioned games such as "Super 3D Noah's Ark" don't have one. To play the game, one needs to first insert the game in the console and then plug an official cartridge on top. The CIC bus lines are forwarded from Noah's towards the official game's CIC!
ROM: instructions & assets
I was unable to find a list of all SNES games with their ROM size. So I made my own. That is 3,378 titles (across USA/Japan/Europe) presented in the chart below.
Games ROM size used to be expressed in bits instead of bytes. Zelda III, for example, was not advertised as 1,048,576 bytes but the size of its ROM in bits, that is 1,048,576 * 8 / (1024*1024) = 8Mb. The largest game ever released was Star Ocean (48Mb or 6,291,456 bytes) while a masterpiece such as Super Mario World used a mere 524,288 bytes (4Mb) ROM.
If you don't want to click on the .csv , here are the most noteworthy games (feel free to scream me an email if your favorite game is not in the list).
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