The Insane Engineering of the Gameboy

The original Gameboy was launched  in 1989 and was received with  

mixed reviews. While its success is  ingrained in our cultural memory now,  

when it was launched it was a  technologically inferior product.

The Gameboy was designed  to be a cheap, low-powered,  

portable gaming system. It was limited  in many ways. No backlight for the  

screen and incredibly low installed  memory available for coding games.

Review magazines of the time viewed these  features as a negative, but these compromises  

in design were exactly why the Gameboy  succeeded. This was a console for the masses.

Even with these limitations, engineers  and programmers came up with ingenious  

methods to create games that have  not only stood the test of time

but launched some of the most valuable franchises  

in the history of the entertainment industry.  TV shows, movies, toys, and even theme parks.

This is the insane engineering  of the Nintendo Gameboy.

The Game Boy's simple design borrows  much of its success from its older  

brother the NES. A straightforward  and familiar controller setup.

Nintendo knew that size and weight were the most  important factors for a system to be portable.

The Gameboy was almost half the  size and half the weight of its  

competitors. Just under 15 cm in height and 3  centimeters thick, it weighed only 220 grams.

This 35-year-old console doesn’t feel oversized  like the mobile phones of this era. Gameboy  

focused on user experience from the get-go, an  ethos that has defined Nintendo to this very day.

But how did Nintendo manage to make the Gameboy  so much smaller and lighter? To begin, one of  

the primary technological limitations  of the early 90s were these things.

Alkaline batteries. While our Gen Z  audience may recognize these as the  

batteries they have to replace in their TV  remote once in a blue moon. These things  

were everywhere in the 90s. Costing about 50  cents each, or about 1.16 in today’s money.

I spent every penny of my pocket money getting  these batteries to power my Gameboy in the 90s.

Large, bulky, non-rechargeable,  and expensive. Minimising their  

use as much as possible was going to give  Nintendo an edge over their competitors.

The Game Boy's main competitor,  

the Sega Game Gear, used 6 AA batteries.  While the Gameboy used just 4. This of  

course saved space, made the Gameboy more  compact, and saved money for the consumer.

Especially as the Gameboy batteries lasted vastly  longer despite having less energy available.

The Game Gear’s 6 AA batteries supplied 4.5  watts to power its electronics. Draining the  

6 batteries in just 3 hours. Costing about  2 dollars and 30 cents per hour of gameplay.

The GameBoy, with its 4 batteries allowed up to 30  

hours of gameplay. It cost just  16 cents per hour of gameplay.

Imagine being me in the 90s. Trying to explain  to my father, who remembers when someone got a  

car for the first time in his village, that  I needed money for a new set of batteries  

every two weeks. Well, for the Sega Game  Gear that was likely closer to every day.

One of the keys to Nintendo's success was  recognizing this limitation and working around it.

While the Game Gear featured a fully lit  coloured LCD screen. The Gameboy featured  

a monochrome screen that was capable of  displaying just 4 shades of green that  

were impossible to see in darkness  because it didn’t have a backlight.

While the Game Gear may have gotten better  reviews with its power-hungry electronics,  

the Gameboy got the customers with  a system that drew just 0.7 watts.

The Game Boy's engineers were determined to use  low-powered screens, and despite this screen being  

a huge part of our nostalgia today, it almost  led to the cancellation of the entire project.

The best available low-powered LCD  screens in the 80s worked by having  

a passive matrix of electrodes  that controlled a grid of pixels.

A pixel consisted of some liquid  crystals sandwiched between two  

perpendicular polarising filters. At rest,  these liquid crystals twist the light that  

bounces off the backplate, which allows the  light to pass through the set of filters.

These crystals respond to voltage changes,  untwisting as voltage is applied, when this  

happens less light can pass through. Early  prototypes of the original Gameboy used liquid  

crystals that naturally twisted only 90 degrees  at rest. These 90-degree structures slowly untwist  

with voltage with the amount of light transmitted  being proportional to the voltage applied.

However, there was a problem. This slope is  not steep enough. This was a problem for the  

low-powered passive grid matrix displays  used in the early versions of the GameBoy.  

The low-power screen used tiny changes in  voltage to differentiate between on and off,  

and the difference in voltage needed to  turn the pixels on and off was too large.

A slight difference in voltage resulted in a  very subtle difference in the amount of light  

emitted by individual "on" and "off" pixels.  In other words, the contrast was very low.

This got worse as the passive matrix  created an interconnected set of pixels  

where voltage could leak into neighbouring  pixels. So neighbouring pixels would also  

be slightly activated resulting in a blurry  image that looked even worse from the sides.

When Nintendo's President Hiroshi  Yamauchi tested a version of the  

Gameboy with these 90-degree twist screens  he actually cancelled the entire project.

However, a breakthrough occurred in  the late 1980s. SHARP perfected a new  

type of LCD screen known as Supertwisted Nematics.

These screens used crystals with twists  between 180 and 270 degrees. These extra  

twists made a sharper transition  between on and off possible.

This is what a super twisted crystal  transition curve looks like. The  

transmitted light drops off rapidly  with a much smaller voltage change.

This technology resulted in sharper black and  white pixels, with the green colour of the gameboy  

being a byproduct of the polarising filters tint,  but how did the gameboy create 4 shades of green.

It was not possible to create these shades  with 4 different voltages settings. Instead  

the gameboy created different shades  by quickly pulsing the pixels on and  

off. Faster pulses result in darker shades,  while slower pulses result in lighter shades.

This is the same technique that  LEDs use to brighten and dim. We  

can’t perceive the pulsing with our  eyes, but cameras can pick it up.

The quest to make the system as cheap as  possible of course created limitations elsewhere.

The 8-bit CPU could only handle 64 kilobytes of  memory, less than a single frame in this video.

Programming a game like Super Mario Land with so  

little memory available required  some creative problem-solving.

All of the Gameboy functions, maths,  

and logic happened by simply reading or  modifying those 64 kilobtyes. Some are  

read from the Gameboy itself while others  are read from the inserted game cartridge.

These 48 numbers, for example, are read from  the cartridge every time the Gameboy is turned  

on and every licensed game cartridge has to have  the exact same hard-coded data at this location.

This is the data it reads, just numbers. But,  

by rearranging them and converting them  to binary we can start to see a familiar  

pattern. Turning off the pixels with ones we  can make out that nostalgic logo that dropped  

into the screen before any game. Inside the  Gameboy, there is a copy of these same numbers.

During the boot-up process, the Game  Boy displayed the logo stored in the  

cartridge while comparing it to the  one in the system, byte by byte.

If a faulty connection caused a byte to be read  incorrectly, the Game Boy would not start up.

Unintentionally, this sparked a  magical tradition among kids worldwide.

A technique that transferred across  cultures and continents before the  

internet existed to share that  knowledge. Take the cartridge  

out and blow on it to remove any dust  that may be causing faulty connections.

For this byte-by-byte comparison, they could  have used any numbers or any image. But  

they intentionally used the trademarked  Nintendo logo to curb bootlegged games.

If you were an unlicensed game  developer, this forced you to  

display Nintendo’s trademarked logo, and  if Nintendo did not permit you to use it,  

you would be breaking trademark laws  even if the games themselves were not.

However, using individual bytes to create the  image, the way the Nintendo logo was displayed,  

is not a very efficient way of  populating the full screen for games.

If the 160 by 144 pixel wide  screen had to address each  

individual pixel it would need  a list of over 23,000 numbers.

Dedicating a whole 35% of the available directory  only to set the screen makes no sense. The real  

amount of space dedicated to creating images  is only 12.5% of the available directory.

But how did such a small memory create  graphics? The key here is the use of tiles.

These are the tiles for the game Super Mario  Land 2, a classic Super Mario scrolling  

game. Each tile consisted of a square of 8x8.  Rather than building the frame pixel by pixel,  

The Gameboy system rendered the  screen in a three-step process.

The CPU would first assemble a  background made out of 32x32 tiles.

But the size of the Gameboy screen only  fits 20 tiles on one side and 18 on the  

other. So a viewing box has to be  placed on top of this background.  

This view box could move along the  background enabling smooth scrolling.

It also has a local coordinate system  that allows non-movable information,  

like lives or scores, to be visualised  consistently in the same location.

Movable objects like Mario or  goombas that can interact with  

the background have a special  name, they are called sprites.

Sprites are just 8x8 pixel-wide tiles that can  be flipped or rotated. For larger characters  

like Mario, a set of 4 sprites was  needed to make the full character.

Once the frame was ready to be visualised,  

the Gameboy went line by line setting the pixel  values on the screen. This is called a line scan.

This practice was a bleed-over from the  NES, which was designed to be used with  

the tracing rays of cathode ray tube  screens. CRTS work by altering the  

path of a beam of electrons to hit against  a screen coated with fluorescent chemicals.

This technique allowed programmers to create  animations. At the end of each line scan,  

Nintendo gave the programmers the choice to pause  

the line scanning mid-frame to adjust  the position of the viewing window.

This is the intro to the Links Awakening  game. This was all created using a static  

background. Once the background was assembled  the tiles and the screen location were set,  

and the line scan would start. Here a pause would  happen and the viewing window would be moved a  

tiny bit. Then the line-scan would restart the  drawing and the end product emulated movement.

The enemies in Link's Awakening like this or the  intro to some games like TITUS were all created  

using these techniques. Even racing games used  mid-frame pauses to create the curves in the road.

This design ideology of simplifying  also affected the audio of the console.  

The Gameboy came with only one speaker  that was controlled by only 4 channels.

Two square wave tone generators, one white  noise maker, and a separate channel that  

could load any custom waveform that is  stored in the game cartridge. That's it.

Lets create a song by sending the desired  

frequencies and timings to the  first two square wave channels.

Now lets add our custom chipped triangle wave  

to the fourth channel with it’s  frequency and timing parameters.

Now, the final touch, a little  percussion to highlight the beats,  

made with the white noise channel.

This style of music is a huge part  of our nostalgia and love for the  

Gameboy. I can hear the intro to the  pokemon games in my head to this day.

But games are more than just images and sounds,  

they are fully fledged stories  that need data and space for logic.

Of the 65,000 numbers that the Gameboy reads,  

only half of them are read from the cartridge.  This worked fine for simple games like Tetris,  

where the full instructions and data needed  to run the game was less than 32,000 numbers.

Limited data was common in the 80's so game  developers developed a technique called  

memory banking where the game divides the data  into smaller sections or banks. Essentially,  

the game dynamically switches between  different banks of memory to access a  

larger pool of data than the  hardware originally allowed.

The Game Boy's hardware can only read  32 KB of data but Pokemon Red/Blue has  

a memory size of 373 kB. The data  had to be divided into 44 banks.

As the player explores different areas,  the game seamlessly switches between these  

memory banks to load and unload the relevant data. 

This is controlled with a small  chip inside the cartridge.  

When the Pokedex was opened the chip  would access “Bank 2B” where all the  

151 Pokemon had a 100-character description  that was printed on the screen using tiles.

If the player entered a Pokemart  the chip would access Bank 1 to  

get the prices of each item. As the  player moves between towns, locations,  

or activities, the game continues to  manage these memory banks dynamically.

The engineers in Nintendo made  a choice that allowed them to  

get consoles into the hands of gamers  around the world. For many, like me,  

it was their first experience of video games.  With a launch price of just 89 dollars it was  

significantly cheaper than either of its two  main competitors, and vastly cheaper to run.

This ethos of player first is what defined  Nintendo as a company. While its competitors  

focused on ever increasing hardware specs,  Nintendo focused on accessibility. The Nintendo  

Wii with its motion controllers introduced  hundreds of thousands of older people who weren’t  

familiar with traditional game controls to gaming.  The Nintendo switch doubles as both a portable  

gaming console and docked home console, with  detachable controllers that have allowed me and  

my friends to have impromptu mario kart sessions  in airports and hotel rooms. Nintendo are masters  

of interactive design and the Nintendo Gameboy  was a generational defining piece of design.

Devices like the GameBoy were  designed for a simpler time,  

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