An MCU is an MOS digital IC designed for stand-alone operation that includes a programmable processing unit, program memory, read/write data memory and special I/O capability. The processing unit contains an instruction decoder, arithmetic logic unit (ALU), registers and additional logic. Fetching and executing instructions and manipulating data held in on-chip program, data memory and registers determine the MCU's operation. MCU devices must be available with on-chip program store (ROM, EPROM and flash, among others -- cache memory is an inadequate qualifier for an MCU). The most significant characteristic of a given MCU is its selection of on-chip peripheral circuits that assist the processor with sophisticated input, output and control functions.
An ASIC (application-specific integrated circuit) is a microchip designed for a special application, such as a particular kind of transmission protocol or a hand-held computer. You might contrast it with general integrated circuits, such as the microprocessor and the random access memory chips in your PC. ASICs are used in a wide-range of applications, including auto emission control, environmental monitoring, and personal digital assistants (PDAs).
An ASIC can be pre-manufactured for a special application or it can be custom manufactured (typically using components from a "building block" library of components) for a particular customer application.
The general-purpose logic category includes semiconductor products that serve a general-purpose logic function and includes the following FPGAs/PLDs, standard logic and flat-panel/LCD drivers:
FPGA/PLD -- End users customize FPGAs and PLDs after assembly. Included in this category are FPGAs, complex PLDs and simple PLDs. Other parts included are programmable array logic, generic ray logic, electrically PLD, programmable logic array and field-programmable logic.
LCD Driver -- This display driver IC is designed to control and drive LCDs. LCD drivers convert digital inputs into the multilevel signals needed to drive LCDs. Excluded from this category are MPR controller/driver ICs that include the LCD drive function and TV LCD drivers that accept analog video inputs. These devices are counted as part of the microcomponent category or analog IC category, respectively.
Standard Logic -- This refers to commodity family logic with fewer than 150 gates; it is sometimes referred to as "glue" logic. Examples include HC/HCT, AC/ACT, FACT and 74BC/BCT BiCMOS family logic.
Other Logic -- These devices are used in general-purpose applications and are high functionality (greater than 150 gates).