go back to 0.0 go to 1.2 1.0 What is inside the Game Boy

The GameBoyTM is a portable device with simple operation. The user interface comprises four buttons, a joypad, integrated four color gray scale screen and a speaker. Stereo sound is available from the headphone jack. The internal hardware includes a Z80 processor derivative together with system RAM and ROM.
These features make the GameBoyTM ideal for menu controlled applications. Programming a a home telephone system for example would be much easier using the GameBoyTM LCD and joypad than using the telephone pad.

1.1 Technical Details

The following table provides more detailed technical information on the hardware inside the GameBoyTM


8-bit Z80-like CPU running at 4.194304MHz

BUS architecture:

8-bit data-BUS, 16-bit address-BUS


8kB internal can be extended to up to 32kB external

Video RAM:

8kB internal


16kBit, 32kBit, 64kBit, 128kBit,... up to 4MBit cartridges are known.


4 channels. Each of which can be mapped either to the left or to the right or to both speakers.


Display: Reflective LCD 160x144 dots (physically)
Colors: 4 shades of gray
Sprites: 40 sprites 8x8 / 8x16


One serial port. Up to 4 GameBoyTM can be connected together using these ports. Baud rate and protocol are not fully documented.


Classic: 6 Volts, 0.7 Watts, 4 AA Batteries - 35 hours
Pocket: 3 Volts, 0,9 Watts, 2 AAA Batteries - about 25 hours

Further information can be found in "gbspec.txt“. Titled "Everything You Always Wanted To Know About GameBoyTM but were afraid to ask“. It is one of the best sources of information for both hardware and software including useful algorithims and common problems/pitfalls.

Figure 1: General hardware schematic

go to Figure 1.1: GB Hardware Figure 1 shows a schematic of the GameBoyTM internal hardware. Starting from the left, there are the buttons and joypad, the serial port, an oscillator, the speakers, the CPU and the main memory. On the lower side the connector to the cartridge is shown. For further information on the GameBoyTM internal hardware and logic use this schematic (Figure 2) drawn by Jeff Frohwein.

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go to 1.2 This document was created with StarOffice 4.0 by Marc Rawer