Blog Post - Aticleworld

Designing High-Speed SPI: The Pitfalls of Open-Drain Buffers and Pull-Ups

Serial Peripheral Interface (SPI) is widely used in embedded systems to communicate with external Flash memory, displays, ADCs, sensors, and other peripherals. Its simple architecture, full-duplex communication, and support for high data rates make it a popular choice in microcontroller-based designs. Configuring an SPI peripheral is usually straightforward. Select the clock frequency, configure the clock

Designing High-Speed SPI: The Pitfalls of Open-Drain Buffers and Pull-Ups Read More »

ADC Interview Questions and Answers: Basic to Advanced

Analog-to-Digital Converters (ADCs) are used in almost every embedded system where a microcontroller needs to work with real-world signals such as voltage, temperature, current, or sensor data. Because of this, ADC interview questions are very common in embedded systems and firmware interviews. In this article, we will cover ADC interview questions and answers from basic

ADC Interview Questions and Answers: Basic to Advanced Read More »

Understanding Atomic Read-Modify-Write in ARM Cortex-M

Have you ever written REG |= BIT and assumed it was a safe way to set a bit? It certainly looks like a single operation. However, on an ARM Cortex-M processor, the CPU actually performs it in three steps: read, modify, and write. If an interrupt happens between these steps and updates the same register,

Understanding Atomic Read-Modify-Write in ARM Cortex-M Read More »

When UART Talks to Itself: The Optical Probe Loopback Bug Nobody Expects

During the development of optical communication firmware for smart meters, a strange field issue was reported: “Communication randomly drops. Works perfectly on the bench. Fails in the field.” To investigate the issue, I swapped cables, verified baud rates, and analyzed logic analyzer captures frame by frame. Everything appeared correct until I noticed that the optical

When UART Talks to Itself: The Optical Probe Loopback Bug Nobody Expects Read More »

C Macro Override Bug: When #define Breaks Build System Configuration

In embedded firmware development, configuration is often controlled through compiler macros passed from the build system. This keeps the codebase flexible and allows easy customization for different products or hardware variants. In this blog post, we will explore how a macro can introduce a subtle bug, often referred to as a C macro override bug

C Macro Override Bug: When #define Breaks Build System Configuration Read More »

How to Detect Rising and Falling Edge of a Bit in C/C++

When working with C or C++ in embedded systems and firmware development, the ability to Detect Rising and Falling Edge of a Bit in C/C++ is essential. This technique is widely used when developing firmware for microcontrollers such as STM32, NXP, and TI to monitor digital signals, status registers, and hardware events reliably. In embedded

How to Detect Rising and Falling Edge of a Bit in C/C++ Read More »

How to Detect Bit Changes in C/C++ Using the XOR Operator and Bit Masking

When working with C or C++, particularly in embedded systems and firmware development, the ability to detect bit changes in C/C++ is essential. Because instead of writing: bool flag1; bool flag2; bool flag3; bool flag4; bool flag5; bool flag6; In embedded systems, we often store multiple related status flags inside a single variable. Generally, we

How to Detect Bit Changes in C/C++ Using the XOR Operator and Bit Masking Read More »

How to Interface a DC Motor with Arduino | Speed & Direction Control

In this tutorial, you will learn how to interface a DC motor with Arduino using a motor driver IC (L293D). DC motors are widely used in embedded systems for motion control applications such as robots, conveyor belts, automatic doors, and small automation projects. Many beginners try to connect a DC motor directly to the GPIO

How to Interface a DC Motor with Arduino | Speed & Direction Control Read More »

L293D Motor Driver IC: Pinout, Applications, and Circuits

The L293D is a 16-pin dual H-bridge motor driver integrated circuit used to control DC motors and stepper motors with low-power control signals from a microcontroller. It acts as a bridge between a microcontroller and your motors. Since microcontrollers operate on low voltage and cannot supply enough current to run a motor directly, the L293D

L293D Motor Driver IC: Pinout, Applications, and Circuits Read More »

Blink Multiple LEDs at Different Speeds on STM32

Blinking an LED is usually the first program written by a beginner on any microcontroller. It is simple, easy to understand, and helps confirm that the board, clock, and GPIO configuration are working correctly. But once you move beyond this basic step and want to blink multiple LEDs at different speeds on STM32, things are

Blink Multiple LEDs at Different Speeds on STM32 Read More »