What is the difference between using an internal vs. external oscillator in STM32?
Using an internal vs. external oscillator in an STM32 microcontroller affects clock accuracy, stability, cost, power consumption, and design complexity. Here's a comprehensive breakdown of the differences: 1. Internal Oscillator (e.g., HSI, MSI, LSI) What it is: Built-in oscillator in the STM32 chip. Common types: HSI (High-Speed Internal): Typically 16 MHz MSI (Multi-Speed Internal): Used in STM32L series (100 kHz to 48 MHz) LSI (Low-Speed Internal): ~32 kHz, for watchdogs or low-power timing Advantages: Feature Description No external components Reduces BOM cost and PCB complexity Lower power Especially MSI for low-power modes Faster startup time Ideal for wake-up from sleep modes Space saving No external crystal required Disadvantages: Feature Description Lower accuracy ±1% to ±3% frequency variation (temperature, voltage dependent) Not suitable for USB USB and precise UART require exact timing Limited stability May drift over time and temperatu...