SA-1

Nintendo · 1995 · Nintendo SA-1 (Super Accelerator 1)

A second, three-times-faster 65C816 processor built into Super NES cartridges from 1995. It powered 35 games, including Super Mario RPG and Kirby Super Star.

The Super NES's main CPU, the Ricoh 5A22, runs at no more than 3.58 MHz, and by the mid-1990s developers wanted more processing power than it could provide. Nintendo's answer was to put a faster processor inside the cartridge. The SA-1, introduced in 1995, contains a processor core based on the same 65C816 architecture as the console's CPU, but running at 10.74 MHz — three times the 5A22's top speed. Because it used the same instruction set, the SA-1 was easier to program than graphics co-processors such as the Super FX: developers could run game logic on it with familiar code while the console's own CPU handled other work. The chip also added 2 KB of fast internal RAM, programmable timers, memory-mapping features, arithmetic functions for multiplication, division and cumulative sums, new DMA modes including conversion from bitmap to the SNES's bitplane graphics format, and built-in copy protection. Thirty-five Super NES games used the SA-1. The best known are Square's Super Mario RPG: Legend of the Seven Stars and HAL Laboratory's Kirby Super Star and Kirby's Dream Land 3 — late-generation games whose busy screens and complex systems the base console could not have handled alone.