This article provides a detailed solution to the “com.mongodb.MongoSocketOpenException: Connection refused” error that occurs when starting a Spring Boot project—even without any MongoDB configuration. It explains why the mongodb-driver-sync dependency triggers auto-configuration and offers two methods to disable MongoAutoConfiguration, helping developers quickly troubleshoot similar issues. 1. Background & Environment Overview To meet business requirements, a…

Wondering why Python lists can resize automatically? Why is append() fast but insert(0) slow? Starting from the C source code of CPython, this article disassembles core structures such as PyObject and PyListObject, analyzes underlying functions like list_resize() and list_append(), and completely reveals the static array essence of dynamic lists. It helps Python developers understand the…

A complete guide to UART serial communication: Learn underlying principles, protocol parsing with state machines, ECharts visualization, and fix garble/loss. Ideal for embedded & IoT engineers. As one of the most fundamental communication methods in embedded systems and the Internet of Things (IoT), serial communication (UART) is a core technology that every hardware/software engineer must…

An in-depth guide to Python circular imports, explaining why they occur, how they crash production systems, and how enterprise teams like Instagram detect and prevent them at scale using static analysis, runtime monitoring, and architectural refactoring. How a simple import statement can bring down your entire application—and why enterprise teams are investing millions in detection…

01 Introduction to MCPWM The ESP32-S3’s MCPWM (Motor Control Pulse Width Modulator) is a versatile PWM generator widely used in applications such as motor control, digital power supplies, and LED dimming. Through multiple timer, operator, comparator, and generator modules, it achieves high-precision and high-efficiency PWM signal output and supports advanced features such as fault detection,…

01 Introduction 1. ESP32-S3 Partition Table   It is a configuration mechanism for dividing the SPI Flash storage space. It works similarly to the partitioning of a computer hard drive, dividing the Flash into multiple areas, each area is used to store different types of data or programs, such as: 2.  Connecting ESP32-S3 to SPI Flash ESP32-S3 communicates…

Learn how to create an interactive CLI application with Node.js for collecting and saving real estate sales data. Master user input prompts, data validation, JSON file handling, and error management to build practical and efficient CLI tools. Introduction Command Line Interfaces (CLIs) are powerful tools that allow users to interact with applications through text-based commands….

1. What is Adobe Creative Cloud (All Apps)? Adobe Creative Cloud, often called the Adobe All Apps Plan or simply Adobe Suite, is a comprehensive set of professional software tools developed by Adobe. It covers almost every creative field: graphic design, photo editing, video production, animation, digital publishing, UI/UX design, and office productivity. Unlike standalone…

A complete guide to STM32 GPIO modes. Learn about Push-Pull, Open-Drain, Alternate Functions, Floating, Pull-Up, Pull-Down, and Analog inputs, with circuit diagrams, register explanations, and practical applications. Preface: STM32 has eight modes, as follows: The STM32 standard IO structure diagram is as follows: The following circuit is a protection circuit. When the voltage is greater…

Discover the stunning cross-section photography of electronic components in Open Circuits. From resistors and capacitors to LEDs and transistors, explore the hidden structures and artistry behind everyday electronics. In the world of electronics, names like resistors, capacitors, and transistors sound cold and seemingly mere functional symbols. But when we cut them open with cameras and…