This article details the “interrupt service routine variable not updating” issue in embedded ARM development, which stems from compiler optimization and missing volatile modifiers. It uses examples to explain errors caused by compiler “redundant load elimination”, illustrates how the volatile keyword prohibits register caching and maintains instruction order, and compares optimization differences at the ARM…

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…

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…

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…

What is BadUSB? Using the STM32F407 development board, we’ll study HID device development and implement a low-cost BadUSB. This article uses the development board for testing. Those with the means can also create a PCB prototype and print the enclosure to create a highly realistic BadUSB.BadUSB is an attack that masquerades as a USB HID…

Many engineers and hobbyists often confuse the applications of ferrite beads, 0Ω resistors, and inductors.In our previous discussion, we compared these three basic components from four perspectives—appearance, schematic symbols, internal structure, and practical applications (Ferrite Beads vs 0Ω Resistors: Principles, Characteristics, and EMC Application Guide). However, one question remained unanswered: When implementing single-point grounding, should…

There’s a small component that can be used just like a 0Ω resistor, but it can also function like an inductor.Can you guess what it is? Yes—it’s the ferrite bead. Today, we’ll explore ferrite beads in detail. To make things easier to understand, we’ll compare ferrite beads directly with 0Ω resistors. 1. Appearance Let’s first…