This F411CEU6 development board is designed for learning and prototyping with STM32F4 microcontrollers. It features a 25MHz high-speed crystal oscillator and a 32.768kHz 6pF low-speed crystal. The V3.0 version uses a lead-free process and gold-plated pin headers for better durability and environmental friendliness. Flash pads are reserved, and USB disk & FATFS routines are provided for easy storage expansion. Supports MicroPython programming with available firmware (configuration file link included, but no technical support). The board comes with a pre-burned HID FW Bootloader (factory test version, hex not provided). Bootloader allows firmware download via a Type-C cable—no USB-to-serial, debugger, or driver needed. Enter bootloader by holding the KEY button, pressing reset, releasing KEY after LED C13 flashes. Boards V1.3 and above have three buttons: reset, BOOT0, and user button. Two methods to enter ISP mode: 1. Press and hold BOOT0 + reset (power on), release reset, then release BOOT0 after 0.5s. 2. With power off, hold BOOT0, power on, release BOOT0 after 0.5s. DFU mode: connect to computer via data cable; if unrecognized, warm chip slightly (~25°C) and re-enter ISP. Serial port mode: use USB-to-serial on PA9/PA10. Model: STM32F411CEU6 / STM32F401CEU6. Color: black. Material: plastic. Package includes: 1 * Development Board (no other accessories). Note: color may vary slightly due to lighting/monitor; measurement error ±1-3 cm.