Working of Nintendo 64

How N64 Works

History

Just as Atari ushered in the dawn of the home video game, Nintendo is largely considered to be the company that revolutionized the industry with the introduction of the Nintendo Entertainment System (NES) in 1985. An 8-bit system based on the 6502 processor and some custom chips, the NES came together with Super Mario Brothers; this inclusion of an accurate home version of one of the most popular arcade games at the time turned out to be pure genius. Sales of the NES were phenomenal. This established Nintendo as the dominant home video game manufacturer until the late '90s, when it was eclipsed by the rival Sony PlayStation.

Competition from 32-bit systems prompted Nintendo to develop the 64-bit system that became known as Nintendo 64.

In 1989, Nintendo introduced a new 16-bit system dubbed the Super Nintendo Entertainment System (SNES). Within a couple of years, rivals had introduced 32-bit systems that eclipsed the capabilities of the SNES. So, Nintendo announced an agreement with Silicon Graphics Inc. (SGI) to develop a new 64-bit video game system, code-named Project Reality. Although SGI had never designed video game hardware before, the company was regarded as one of the leaders in computer graphics technology.

After several years of development, the system was finally released in 1996 as the Nintendo 64. But the delays and shortage of games during the first year of availability gave the advantage to Sony, who had released the PlayStation over a year earlier. Nintendo is facing the same situation again with the Sony PlayStation 2 debuting in 2000, while Nintendo's Gamecube is not due until Fall 2001.

Console

Let's take a look at the components inside an N64, and what their capabilities are.

• Processor: 64-bit R4300i "Reality Engine"
  • Processor clock speed: 93.75 MHz
  • Bus speed: 562.5 MB per second
• Co-Processor: "Reality Co-Processor," 62.5 MHz custom chip that combines two systems:
  • Graphics: "Reality Immersion Processor"
    • Processor clock speed: 62.5 MHz
    • MIPS (Million Instructions Per Second): 500
    • Resolution: 640x480, 320x240 or 256x224 interlaced
    • Colors: 21-bit (2,097,152) maximum
    • Polygon rendering: 150,000 polygons per second
    • Geometry engine:
      
      • Anti-aliasing
        
      • Perspective correction
      • Gouraud shading
      • Trilinear mip mapping
      • Environment mapping
    • Memory: uses system memory
  • Audio: "Reality Signal Processor"
    • Channels: 64
    • Sample rate: 44.1 KHz
    • Memory: uses system memory
• Memory: 4 MB Rambus D-RAM (expands to 8 MB)
• Operating system: Proprietary
• Game medium: Cartridge

Similar to the PlayStation, the CPU in the N64 is a RISC processor. RISC stands for reduced instruction set computer, and means that the instructions and computations performed by the processor are simpler and fewer. Also, RISC chips are superscalar -- they can perform multiple instructions at the same time. This combination of capabilities, performing multiple instructions simultaneously and completing each instruction faster because it is simpler, allows the CPU to perform better than many chips with a much faster clock speed.

Nintendo 64 uses a customized chip that handles all the components.

To lower production costs, the CPU, graphics and audio processors are combined into a single application specific integrated circuit, or ASIC. Simply put, the ASIC is a customized chip created to manage all of the components that would otherwise be handled by three separate chips.

Some special features of the N64 include perspective correction and trilinear mip mapping. Perspective correction makes the texture map resize at the same rate as the object that it is mapped on.

Trilinear mip mapping is a cool process. In this form of texture mapping, three sizes of each texture map are made, a large, a medium and a small version. In essence, it replaces the appearance of an object with a more detailed image as you move closer to the object in the game. Let's take a look at how it uses these maps:

• The system calculates the distance from your viewpoint to an object in the game.
• The system loads the texture maps for the object. Our three maps will be 64x64 (large), 32x32 (medium), and 8x8 (small).
• The system determines the exact size that the image map needs to be -- let's say 16x16 for our example here.
• Based on the size, it decides which two texture maps to use. For our example, it might choose the medium and small texture maps.
• It then interpolates (averages) between the two texture maps, creating a custom texture map that is 16x16, which it then applies to the object.

Environment mapping is no less amazing. Simple in concept, it means that reflections of objects are rendered and mapped onto the reflecting surface. The sheer amount of calculating that is done by the graphics processor to determine the angle and transparency for each reflected object, and then render it in real time, is extraordinary. An incredible number of calculations have to happen for every single polygon in a game. And there can be over a hundred thousand polygons on the screen at any given time!

The games come on proprietary ROMs housed in plastic cartridges. When a game is put in the console, the following happens:

• You turn the power on.
• The console loads portions of the operating system from ROM into RAM.
• The game initialization sequence is loaded into RAM.
• You interact with the game via the controller.
• As each specific part of the game is requested, the application code, video, audio and hardware-render geometry are loaded into RAM.
• The CPU coordinates everything. It receives the input from the controller, pulls the data from RAM and directs the graphics and audio processing.
• You are finally beaten by the game and turn it off.

Controller

The trident shape of the Nintendo 64 controller is unique among video game systems.

The controller is the primary user interface for the N64. With its trident shape, it is probably the most unusual design for a controller on the market today. The standard N64 controller has 14 buttons plus an analog joystick. The buttons include:

• Four buttons arranged as a directional pad on the top left
• Start button in the top middle
• Six action buttons on the top right
• One action button on the front left
• One action button on the front right
• One action button in the bottom middle
• Analog joystick on the top middle

Inside the N64 controller.

Although each button can be configured to perform a specific and distinctive action, they all work on the same principle. In essence, each button is a switch that completes a circuit when it is pressed. A small metal disk beneath the button is pushed into contact with two strips of conductive material on the circuit board inside the controller. While the metal disk is in contact, it conducts electricity between the two strips. The controller senses that the circuit is closed and sends that data to the N64. The CPU compares that data with the instructions in the game software for that button, and triggers the appropriate response. There is also a metal disk under each arm of the directional pad. If you're playing a game in which pushing down on the directional pad causes the character to crouch, a similar string of connections is made from the time you push down on the pad to when the character crouches.

The analog joystick works in a completely different way from the buttons described above. Two wheels are positioned at right angles to each other below the joystick. Whenever the joystick is moved, the two wheels turn slightly. Tiny slots are arranged around the perimeter of each wheel. The wheels are each mounted between an LED (Light Emitting Diode) and a photo cell. Light from the LED, shining through the slots in the wheel on the cell, creates a small amount of current. When the amount of light changes, the level of current changes. By monitoring the output of each photo cell, the N64 can determine the exact angle at which the joystick is being held, and trigger the appropriate response.

Another feature of the N64 controller is the ability to add options via an expansion slot on the bottom of the controller. A popular option is the Rumble Pak, which provides force feedback. This feature provides a tactile stimulation to certain actions in a game. For example, in a racing game, you might feel a jarring vibration as your car slams into the wall.

Force feedback is actually accomplished through the use of a very common device, a simple electric motor. The shaft of the motor holds an unbalanced weight. When power is supplied to the motor, it spins the weight. Because the weight is unbalanced, the motor tries to wobble. But since the motor is securely mounted inside the Rumble Pak, the wobble translates into a shuddering vibration of the controller itself.

You can save games and high scores by using one of the special Flash memory cards. The card is inserted into the slot on the bottom of the N64 controller.

The N64 controller uses only three wires to connect to the console. There's a ground wire, another wire that supplies +3, 6 volts of power, and a third wire that carries all data. The controller sends the information for each button in sequence, and then receives data back from the console.

Games

Cartridges are unique to Nintendo 64. They offer fast load but small capacity. They are more durable than CDs.

The N64 is the only current system that uses cartridges. There are advantages and disadvantages to this approach:

Advantages

• Fast load times - Sections of a game are transferred almost instantly from the cartridge's ROM to the system's RAM.
• Additional performance features - Since the cartridge contains a circuit board that is plugged into the main system, it can contain special hardware-based enhancements that augment the processing power or special effects of the system.
• Durability - Cartridges are not as easily damaged as CDs, which can be ruined by a simple scratch.

Disadvantages

• Small capacity - Cartridges, ranging from about 8 MB to 96 MB, hold significantly less data than CDs (650 MB).
• Expense - Because of all the hardware, the cost per unit to manufacture cartridges is quite a bit more than to make CDs.
• Audio - Even though the N64 has near-CD quality sound, it is not utilized to the same degree as in CD-based games because of the enormous amount of storage required.

Pokeman Stadium

Although the N64 had only a few games available when it first came out, the number of titles has grown to a considerable library. Used games can be found for less than $15. Many of the new games can cost between $50 and $75.