> Rare, perhaps, but not unique. Sega's 837-12079 light gun board used by Virtua Cop 2 > and other Model 2 games is another FPGA-based solution, here using a Altera FLEX > EPF8282ALC84-4 along with a MB3771 power monitor, various logic and interface chips, > and a Sega 315-5338A I/O controller. Sega's Naomi-era 838-13143 "GUN SENSE HOD" board > instead uses a standard MCU model with an external EPROM, though its architecture > (NEC 78K/2) isn't supported in MAME yet.
I just figured the gun inputs in the Model 2 games controlled by their respective I/O boards. The gun board is a means to send analog data to the I/O board. The Gun Sense HOD board works in a similar fashion.
Carnevil and Invasion: The Abductors is more similar to Area 51: Site 4 where there are normally no adc related devices from the main pcb. Both of them use a PLD device directly mapped to the main cpu.
This marks another pcb set I need to map a schematic of.
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