The Super Famicom’s launch in Japan was run like a security operation. According to Edge’s history, Nintendo collected the first 300,000 consoles from secret warehouses from midnight on 19 November 1990, using a hundred ten-ton trucks carrying 3,000 machines each. A leaked plan by a yakuza gang to hijack two of the trucks was one reason for the secrecy. Every console was in the shops the day before launch, against more than a million and a half pre-orders. The crowds caused such traffic problems that, Edge says, the government asked for future hardware launches to be held at weekends.
The machine inside was built for a particular kind of game. It had a processor from the same 6502 family as the NES, a graphics chip that could rotate and scale a whole background layer, and a separate Sony-made sound unit that played sampled instruments. Nintendo’s figures put lifetime sales at 49.10 million.
Fast facts
- Maker: Nintendo. Hardware development led by Masayuki Uemura’s R&D 2.
- Launched: Japan, 21 November 1990, at ¥25,000; North America, 1991, at about $200; UK, April 1992, at £149.99 with Super Mario World.
- CPU: a 65816-based processor, the Ricoh 5A22, at 3.58, 2.68 or 1.79 MHz depending on the memory being accessed.
- Memory: 128K of work RAM and 64K of video RAM.
- Picture: 256×224 pixels as standard, up to 512×448 interlaced; eight background modes, including Mode 7.
- Colours: a palette of 32,768; 256 palette entries on screen at once.
- Sprites: 128, in sizes from 8×8 to 64×64, at most 32 on a line.
- Sound: a Sony SPC700 sound processor with 64K of its own RAM and a DSP playing eight voices of compressed samples at 32 kHz.
- Sales: 49.10 million, by Nintendo’s count.
Speed depends on the cartridge
The main processor is a 16-bit 65816 core, built into a Ricoh chip with Nintendo’s DMA controller and other hardware. Its clock speed is not fixed. Nintendo’s development manual says the clock switches automatically “depending on the address to be accessed”: 3.58 MHz, 2.68 MHz or 1.79 MHz. Ordinary cartridge ROM, with an access time under 200 nanoseconds, runs at 2.68 MHz, the default. A game could only run at the full 3.58 MHz from faster, more expensive ROM, under 120 nanoseconds, and publishers had to ask for “High Speed Mode” when they submitted the game to Nintendo. Whatever the address, DMA transfers always run at 2.68 MHz.
It could not play Famicom games. As the Masayuki Uemura entry explains, Nintendo judged backwards compatibility too expensive.
Pictures in layers
The graphics chip, which Nintendo’s manual calls the S-PPU, is really two chips. The manual says PPU1 generates “background character data, rotation, and scaling”, while PPU2 handles “special effects like windows, mosaic, and fades”.
It offers eight background modes, from four layers of four-colour tiles to one layer of 256-colour tiles. The standard picture is 256×224 pixels. The high-resolution modes run at 512×224, or 512×448 with interlace. Colours are stored as 15-bit values, which gives the palette of 32,768. Edge later remembered how often that figure was set against the Mega Drive’s 512, and called it “advertising fodder”, since many of the shades were hard to tell apart on a television. Modes 3 and 4 can skip the palette and take colours straight from the tile data, which the manual says allows 2,048 colours on one layer.
Sprites and their limits
The manual gives the system 128 objects (sprites). Each takes one of eight 16-colour palettes, and a game picks two sizes per frame from the four available. There are also two limits on each line of the picture, which the manual names after the flags that report them:
- “33’s Range Over”. Only 32 sprites can appear on one line. When there are more, the chip keeps those with the lowest numbers.
- “35’s Time Over”. The sprites on a line are drawn as 8-pixel-wide slices, and the chip can only draw 34 slices per line. When there are more, it keeps the slices of the higher-numbered sprites.
So the two limits discard in opposite orders, which the community reference wikis spell out in detail. A crowded line loses its highest-numbered sprites to the first limit and its lowest-numbered slices to the second.
Nintendo’s advice for games that needed more was what it called “virtual OBJs”: change the sprites’ priority order every frame so that different sprites drop out each time. The chip had a function to rotate the priority of all 128 sprites for this. The manual warns that with this method the sprites “will flash every frame”.
Mode 7
In Mode 7 there is one background layer (the manual’s EXTBG mode trades it down to 128 colours to add per-pixel priority). It is built from 256 tiles of 8×8 pixels, each pixel one of 256 colours, laid out on a map 1024 pixels square. The chip can rotate, enlarge and shrink that map around a centre point the program chooses. Mathematically this is an affine transformation. It can rotate, scale, stretch and shear the map, but straight lines stay straight and parallel lines stay parallel, so on its own it cannot draw a road running into the distance.
The illusion of distance comes from HDMA, a DMA mode that, in the manual’s words, transfers data “synchronizing with the H-Blank”, so that “the S-PPU settings can be varied by each horizontal scan line”. A game writes a new set of Mode 7 values for every line of the picture. The lines near the top of the screen shrink the map a lot and the lines near the bottom shrink it little, and the eye reads the result as a flat ground plane. To help with the arithmetic, the chip includes a fast multiplier, which the manual says is there to calculate Mode 7’s rotation values and “lighten the burden of the CPU”. Mean Machines in 1991 described games using the “sprite-twist hardware to create smooth scrolling road graphics”, like Nintendo’s F-Zero.
The limits of the trick show on screen. Mode 7 gives one flat layer, so anything standing up from the ground, such as the other cars in a racing game, has to be drawn with sprites.
The sound is a second computer
The audio hardware is a self-contained unit. Nintendo’s manual describes a Sony “SPC700 series CMOS 8-bit CPU” with a 64-byte boot ROM, three timers and four ports to the main processor, sharing 64K of sound RAM with a digital signal processor (DSP). The DSP plays eight voices at once from samples stored as 4-bit ADPCM, a compressed form of digital sound. It adds echo, a noise generator, envelopes and pitch modulation.
Nintendo called its compression BRR (bit rate reduction). Sound “sampled at 32KHz” is cut from 16 bits per sample to 4, and stored in blocks of nine bytes: a one-byte header and 16 four-bit samples. The whole sample set, and the program that plays the music, have to fit in the 64K of sound RAM alongside the echo buffer.
A game uploads its sound program and samples through the main processor at the start. From then on the sound CPU runs the music by itself, and the main CPU talks to it only through the four one-byte ports. The community SNESdev reference adds the timings: the sound CPU runs at 1.024 MHz, and the DSP produces one stereo sample for every 768 cycles of a 24.576 MHz resonator, which works out at exactly 32,000 samples a second.
The chip’s designer is a matter of record from the machine’s own lifetime. In February 1995 Edge wrote that Nintendo had asked Sony’s audio R&D division for a sound chip, and that “it was designed by Sony’s hardware supremo Ken Kutaragi, the chief engineer who went on to create the chipset for the new PlayStation”. Edge added that Sony kept the rights to programming the chip and “charged Nintendo excessive fees” for information its developers needed.
Chips in the cartridge
Because every game came on a cartridge, Nintendo could add hardware to the cartridge itself. Its development manuals document three such chips: the DSP-1 maths processor, the SA-1 and the Super FX. The Super FX was a graphics processor, and the manual says it ran at 10.74 MHz, “six times as fast as the Super NES CPU”. In 1993 Super Play reported that it was used in only one game so far, Starfox (Starwing in Europe), and that the chip and the game had both been designed for Nintendo by the British 3D specialists Argonaut. The DSP chip went into games including Pilotwings, which Super Play called the first chip-enhanced game, and Super Mario Kart.
America, and Britain twice
In America the Super NES was due in shops that September, Compute! reported in October 1991, “priced around $200”. Edge’s later history gives the launch as 1 September 1991. Other public sources say it began shipping in limited quantities on 23 August 1991, so the exact date is uncertain.
In Britain the machine was on sale long before Nintendo sold it. Mean Machines was reporting on British importers in April 1991, a year before the official launch, and they were competing on picture quality:
Import specialists Advanced Console Entertainment are claiming that their Super Famicoms have better picture quality than any other machines currently available in Britain.
By October 1991 the same magazine reported that Gremlin Graphics was finishing Top Racer, “what must be one of the first Super Famicom games to be programmed in the UK”, to be published in Japan and America by Kemco. British players had the machine and British studios were writing for it, but Nintendo had sold none here.
The official price undercut all of them. Mean Machines in January 1992:
There’s no doubt that in the graphics and sound departments, the Super NES beats the Megadrive hands down and at £149, it’s a real bargain (grey import prices are still around £250 to £300!).
An official machine at about half the price of an import reversed the usual pattern, and the same page reported “industry pundits” already expecting Sega to cut its price, “some people even see the [price] tag dropping down to a tiny £99.99”. The magazine also noted that the Japanese machine “was noted for its particularly ugly concrete block-like appearance”, and had been restyled for the West, and that the new controller’s X and Y buttons “have indentations, so the player can distinguish between them and the A and B buttons by touch”.
The machine arrived in April 1992. Computer and Video Games greeted it with “SUPER NINTENDO HITS HOME AT LAST! … We’ve been waiting for aaages now”, at £149.99 with Super Mario World in the box and F-Zero and Super Tennis on sale alongside it. By February 1993 Super Play was asking “Are the days of the bargain grey import over?”
Sources
- Nintendo, Super NES Development Manual, Book I: the CPU clock and memory speeds, High Speed Mode (section 2, chapter 21, and the software submission requirements); the functions of PPU1 and PPU2, work RAM and video RAM (chapter 22); background modes, resolutions and colours; 128 objects, sizes and palettes; “33’s Range Over”, “35’s Time Over” and virtual OBJs (chapter 20); Mode 7 and the 1024-dot map; the multiplier (chapter 10); H-DMA (chapter 17); the sound source outline, BRR and the 32 kHz sampling rate (section 3).
- Nintendo, Development Manual, Book II: the SA-1, the Super FX at 10.74 MHz, and the DSP-1.
- SNESdev Wiki, “S-SMP” and “S-DSP”, and Super Famicom Development Wiki, “Sprites” (web, secondary, community references): the 5A22 part number, the sound CPU’s 1.024 MHz clock and the 24.576 MHz resonator, and the order in which sprites and slices are dropped. https://snes.nesdev.org/wiki/S-SMP
- The Games Machine issue 34, September 1990: the Japanese launch date, ¥25,000 price and 300,000 first production run.
- Edge issue 123, May 2003, Super Nintendo retrospective: Uemura and R&D 2; the 21 November 1990 launch, “Operation Midnight”, the yakuza plan, pre-orders and the request for weekend launches; the US launch date; its specification box (128K RAM, 64K video RAM, 256 colours on screen, sprites from 8×8 to 64×64).
- Edge issue 17, February 1995, PlayStation feature: Ken Kutaragi and the Super Famicom sound chip.
- Compute! issue 134, October 1991: the US launch “this September”, “priced around $200”.
- Mean Machines issue 7, April 1991 (importers); issue 13, October 1991 (Gremlin’s Top Racer, and “sprite-twist hardware” in F-Zero); issue 16, January 1992 (the £149 price, grey imports, the redesigned case and controller).
- Computer and Video Games issue 126, May 1992: the UK launch at £149.99 with Super Mario World.
- Edge issue 5, February 1994: the UK launch in April 1992.
- Super Play issue 4, February 1993: the grey import headline. Super Play Gold, 1993: the Super FX in Starfox/Starwing and Argonaut, and the DSP chip in Pilotwings and Super Mario Kart.
- Nintendo Co., Ltd., Investor Relations, “Dedicated Video Game Sales Units”: Super Famicom and SNES, 49.10 million (web). https://www.nintendo.co.jp/ir/en/finance/hard_soft/index.html
- Wikipedia, “Super Nintendo Entertainment System” (web, secondary): limited US shipments from 23 August 1991; the end of production. https://en.wikipedia.org/wiki/Super_Nintendo_Entertainment_System