Logic
1. What are Logic Components?
Logic components are the core units that realize the computing and control functions in computer hardware systems. They build combinational logic and sequential logic circuits through logic gate circuits to complete signal processing, data computing, and system control tasks. Its physical carriers include integrated circuits (such as CPU, FPGA) or discrete components, and are widely used in processor design, industrial control, communication equipment, and other fields.
2. What are the Types of Logic Components?
1) Basic Logic Unit
Logic Gate Circuits: AND gates (AND), OR gates (OR), NOT gates (NOT), etc. realize Boolean logic operations and form the basis of all complex logic.
Combinational Logic Circuits: no memory function, the output depends only on the current input (such as decoders, arithmetic logic units ALU).
Sequential Logic Circuits: contain storage elements (flip-flops, registers), and the output depends on the current input and historical state (such as counters and shift registers).
2) Programmable Logic Device (PLD)
√FPGA (Field Programmable Gate Array): Consists of configurable logic blocks (CLBs) and supports hardware reconfiguration. For example:
Xilinx 7 Series: CLBs contain lookup tables (LUT6), triggers, carry chains, and support logic functions, and distributed storage.
Altera Cyclone Series: The basic unit is a logic unit (LE), which contains LUTs and triggers, and integrates wiring resources through LABs (Logic Array Blocks).
√PLA (Programmable Logic Array): Implements specific logic functions (such as F0=AC+ABD) through custom and/or arrays.
3. What are the Key Features and Design Points of Logic Components?
1) Electrical Features
Logic Level Compatibility: we need to match level standards such as TTL (5V) and CMOS (3.3V/1.8V) to avoid signal distortion.
Input/Output Threshold: Parameters such as Vih (minimum input high level) and Vil (maximum input low level) determine compatibility.
Open-drain Output: OC (open collector) and OD (open drain) gates require external pull-up resistors to drive the load.
2) Performance Optimization
Unified Control Signals: Reduce the types of trigger reset/clock and improve resource utilization (such as the shared control set of the trigger of Slice in FPGA).
Dedicated Hardware Acceleration: Carry chain optimizes arithmetic operations, and shift registers achieve efficient data shifting.
4. What are Logic Components Used for?
Central Processing Unit (CPU): ALU performs arithmetic/logic operations, and the controller coordinates the instruction flow.
Communication System: FPGA realizes high-speed data exchange, protocol processing, and signal modulation.
Embedded Control: PLD customizes the logic control and interface management of industrial equipment.
5. Development Trend of Logic Components
Current mainstream FPGAs support scenarios such as artificial intelligence and edge computing through heterogeneous integration (such as embedded hard-core processors) and high-density logic resources (such as ultra-large-scale LE/CLB under 7nm process).