Video game cartridges can be very simple, with just a chip to store the code and a couple of capacitors that filter noise. But over time they became "expansion cards", adding extra memory and special processors to ensure the performance of advanced games. The Super Nintendo is an excellent example of this, with titles that incorporate volatile memory, protection mechanisms, and all kinds of accelerators. Fabien Sanglard's site is full of technical information about Super Nintendo cartridges, and it definitely deserves your attention.
A frequent criticism I'm hearing from users of next-generation consoles is the 30 FPS lock that developers impose on their games. There's always room to optimize and apply visual tricks to improve performance, but the feeling is that consoles are falling short in power.
Obviously, this is not a new phenomenon: classic consoles also suffered with their silicon, but they had two advantages: expansion ports, and special cartridges. Expansion ports allowed the development of accessories like the Sega CD, while some cartridges incorporated secondary hardware so that their games wouldn't be limited by the platform's original specifications. Super Nintendo games followed this path on many occasions, and Fabien Sanglard's site shows us many details about the internal design of their cartridges.
The "secret sauce" of Super Nintendo cartridges
In the first section, Fabien reviews the CIC, a protection system adopted by Nintendo to block the execution of unlicensed titles. In relaxed terms, it's two chips talking to each other, one in the console and one in the cartridge. If the console chip sees something it doesn't like, it sends a reset command to the whole system. The CIC also existed on the Nintendo NES, and some 'alternative' games went so far as to attack the console to disable its chip for a second or two, while on the Super Nintendo, some used the bypass trick.
The size of cartridges grew over the years. For example, Super Mario World from 1990 uses a 4-megabit ROM, and at the other end, the first Star Ocean (1996) and Tales of Phantasia (1995) required 48-megabit ROMs. Naturally, those titans needed a solution to save progress, and lacking local storage in the console, they added an SRAM chip, backed by a CR2032 battery.
Finally, we arrive at the acceleration processors. The most well-known is Super FX from Star Fox, but so far 13 chips, reaching 72 games have been identified. The most used is Super Accelerator 1 or SA-1, essentially a 65C816 processor (the same as the Super NES), running at four times the frequency (10.74 MHz). The CIC becomes integrated into the chip, and it also includes 2 KB of SRAM. In the most advanced configuration, the SA-1 can work in parallel with the console chip, multiplying its performance by five.
Alongside the SA-1 are designs such as the CX4 from Capcom, the CS-DD1, the DSP-1 (present in Super Mario Kart and Pilotwings, among others), and the Super FX2 (the FX1 with double the frequency), which made the Doom port possible. For more details, check the link below!
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