The Game Boy is one of Nintendo's greatest hits, selling over a hundred million units (of various versions) over the years. It's simple, rugged, and very versatile with an immense library of games available. The design is very clever and minimalistic, based on a Z80-derived processor with 8 kB of RAM connected to an LCD and sound system.

Of course it would be an act of sacrilege to dissect a working Game Boy, so I'm not going to. This particular one however, has passed on. This Game Boy is no more. It's expired and gone to meet its maker.... etc. In the name of science I'm going to explore its inner workings (though much work has been done by others already, like reverse-engineering its schematic).

The brains of the Game Boy are located on this circuit board. It houses the CPU (the big chip), two chips with RAM (the rectangular ones), the cartridge connector (huge black thing) and a lot of smaller things.

These are the chips from the circuit board. At the top we see the main CPU, on the left is the audio amplifier, and the chip on the right is one of the RAM chips. Nintendo's product code for the Game Boy is 'DMG', so that's why you see that written all over the chips (and the circuit board as well).

This is what we see inside the CPU. The design is quite special: there are a few blocks like in the centre of this picture, but the bulk of the circuitry consists of vertical bars of digital logic. Unfortunately, it's also quite a boring chip, with no logos, text, artwork or anything unnecessary. There's not even a product type designator, nor its maker's logo (its maker being Sharp). I'm a bit disappointed, I'd at least expected some text, or even better, some hidden Super Mario icons :-)

More vertical bars here, and several pieces of memory. The CPU has 256 bytes of ROM inside, which includes the startup sequence (the well-known scrolling bar with 'pa-ding!' sound).

A close-up of these vertical bars we see everywhere. This shape means that these circuits have been designed by a computer. The designer writes a description of what he wants the circuit to do, and the computer translates this to a circuit consisting of logic gates. These are arranged in bars to make it easier to connect the parts together. High-performance chips such as CPUs often have their circuits placed much more closely together, with much more intricate wiring to minimise signal delay. The Game Boy's CPU however had to be low-cost, and it was based on a tried-and-tested platform anyway (the venerable Z80 CPU), so I guess that's why they stuck with the simple routing.

Below the ROM area we find these weird structures. They look like power transistors to me, but I don't see why they would be here. The DMG-CPU does have an analog audio output built-in, but it doesn't need to provide much power because it's followed by an amplifier before it drives the speaker. They could also be for driving the Game Link port, but that again shouldn't draw too much current.

In this corner we find a test structure (the eight little rectangles). This a very common feature on chips, providing the maker with information on his production process. If only the maker had included his name on the chip... It's quite an anonymous thing like this.