Essential for Microcontroller Experts: A Quick Overview of 20 Classic Circuit Modules

Category of Circuit Modules

Core Functionality

Key Points

Power Management and Protection

Reverse Polarity Protection

Utilizediodes or PMOS transistors to prevent reverse polarity of the power supply; the PMOS solution can reduce voltage drop.

Linear Voltage Regulator

UseLDO chips (such as the AMS1117 series) to provide stable5V or 3.3V voltage.

Surge Current Suppression

By usingRC delay and MOS transistors, suppress the inrush current when powering capacitive loads.

Automatic Power Switching

Achieve seamless switching betweenUSB and external power or batteries, preventing current backflow.

Communication Interfaces

RS232 Communication

UseMAX202/MAX232 chips to achieve TTL to RS232 level conversion.

RS485 Communication

Half-duplex mode requires direction control; full-duplex mode does not.

USB to Serial

PL2303HX, CH340 and other chips achieve USB to TTL UART conversion.

Bidirectional Level Shifting

UtilizeMOS transistors to achieveI2C and other open-drain buses for bidirectional level shifting between different voltage domains.

RS485 Direction Auto Control

Automatically control the transceiver direction usingRC circuits and logic gates, saving MCU IO.

Display and Storage

LCD1602 Character Display

Parallel or serial drive character LCD modules.

LCD12864 Graphic Display

Drive graphic dot matrix LCDs with font libraries, supporting parallel/serial modes.

EEPROM Storage

AT24C02 and other chips store data viaI2C bus.

SD Card Storage

Read and write SD cards viaSPI interface, enabling file systems.

Clock and Reset

Real-Time Clock

DS1302 chip provides accurate year, month, day, hour, minute, and second timing.

Reset Circuit

Dedicated reset chips (such as SP706S) provide power-on reset, manual reset, and watchdog functions.

Analog Signal Processing

Operational Amplifier Circuit

Implement signal amplification, filtering, comparison, and other analog processing..

Voltage Comparator Circuit

Compare analog signals with thresholds, output high or low levels..

Sensors and Signal Conditioning

Signal Filtering Circuit

RC passive filtering or operational amplifiers form active filtering, removing noise.

Diode Clamping Protection

UtilizeSchottky diodes to clamp IO port voltage within a safe range, preventing overvoltage.

Program Download and Debugging

Automatic Program Download Circuit

UtilizeDTR/RTS signals to automatically control the MCU’s BOOT and RESET, achieving one-click download.

JTAG/SWD Debug Interface

Standard program download and online debugging interface for ARM core MCUs.