|If you've looked into romset readme.txt files, or arcade emulator CPU listings, you may have seen a lot of numbers and names of components and maybe even recognized some of them. This is a somewhat simplified overview of how these components make the games work. |
Most TOAPLAN games have a setup like this picture, some games vary a little bit with the CPUs and sound chip (early Toaplan games have 2 Z80's, later Toaplan games have a Hitachi MCU instead of the Z80, but more about that later).
The main components in the picture are named by the most common components, and each have a specific function.
The (Motorola) 68000 serves as the main CPU. All other components are controlled directly or indirectly by this chip. This is where MAIN CODE roms go when loaded.
Some games have a TI32010 DSP for protection. Some code that is vital to gameplay has been put in this chip which either has internal ROM (protected, like Flying Shark) or external ROM which can be analyzed.
The (Zilog) Z80 serves as the sub CPU and handles sound control (and is sometimes called the sound CPU) and I/O reading (Joysticks, buttons, coin counters and start buttons). The SOUND CODE rom contains the data for this chip.
The (Yamaha) 3812 generates sound for the speakers. It recieves synthesizer commands from the Z80 and plays the sound and music for the games. In later games (Truxton 2, etc.) this chip is replaced with a Yamaha 2151.
The GFX UNIT is different between different PCB type boards. The earliest PCB type for Toaplan is the Tiger Heli/Slap Fight graphics (1-layer + sprites), followed by Flying Shark/Twin Cobra (2-layer + sprites, simple priority system), and then Truxton/Zero Wing etc. (4-layer + sprites, more complex priority system) and finally Truxton 2/Snow Bros 2 which has even more features. GRAPHICS DATA roms contains the information for the GFX UNIT, these are often separate for layer graphics and sprite graphics.