25MHZ high speed crystal oscillator & 32.768Khz 6PF low speed crystal oscillator V3.0 version began to use lead-free process, the pin header is gold-plated pin header, more environmentally friendly WeAct FW Bootloader has been burned out of the factory. It is a special factory test version, and hex is not provided. Support MicroPython programming Boards with version V1.3 and above have 3 buttons, reset button, BOOT0 button, and user buttons. How to enter ISP mode 1: Press and hold the BOOT0 button and the reset button under the power-on state, then release the reset button, and release the BOOT0 button after 0.5 seconds 2: Hold down the BOOT0 key when power is off, and release the BOOT0 key 0.5S after power on DFU mode:just use the data cable to connect to the computer, if there is a problem of unrecognized, you can properly heat the chip (25 Celsius), and then re-enter the ISP mode Serial port mode:use USB to serial port to connect PA9 and PA10 of the core board WeAct FW Bootloader No need for USB to serial port, no debugger, no computer driver, just a TYPE-C data cable to complete the firmware download Press and hold theKEY button, click thereset button, LED C13flashes, release theKEY buttonto enter Model:STM32F411CEU6 Colour:Black Material:PCB Package Contents: 2 * Development Board with pin