• 70008 ASIC Core emulates Intel Z80
• cbc7hd and cbc7vx ASICs with avaiable Z80 core
• cbc8hd ASIC with available microprocessor core

These are pre-packaged chip designs that have "building blocks" or cells that consist of things like a variety of different levels of microprocessors (z80 to 386), and digital or analog ICs that are dropped in place by the manufacturer at the request of the designer along with "user defined logic" specified by the designer. A software program ("Sample design kits are available at no charge to qualified users: contact the NEC ASIC Design Center nearest you for more information.") allows the designer to exactly specify the desired configuration and emulate the result prior to e-mailing the spec to the manufacturer for production. This is how the big-boys develop products. The per-chip cost is minimal in quantity and you get to put everything you need (except maybe discreet components like resisters, coils, capacitors, etc...) on one chip which lowers the assembly cost enormously

Advantages:

• Much more complex designs are possible in less silicon since no field programming support need be provided.
• Low cost since production is handled in quantity by the manufacturer.

Disadvantages:

• Once its in production, no changes can be made. These are not FPGAs (at least as far as I can see). Errors are not fix-able in the field.
• No actual testing (only simulation) is possible during design phase.
• To be cost effective, the quantity ordered must be very high. These chips can not be programmed locally, only the manufacturer can "burn the design" into the chip.