Liangxu Linux

Jan 26, 2026 · Fundamentals

Why I2C Needs Pull‑Up Resistors and How to Choose the Right Value

This article explains the open‑drain nature of I2C, why pull‑up resistors are essential for providing a high level, ensuring signal integrity and enabling wired‑AND logic, and offers practical formulas, recommended resistor ranges for different speeds, STM32 configuration examples, and debugging tips.