Repository focuses on EasyThreeD ET4000+ board for K7 and K9 printers. Board shares features with K9, Nano, and Dora printers. Multiple versions available for different K7 models
STM32L432KC has three USART modules: USART1, USART2, and USART3. USART2 module connects to onboard ST-Link programmer via PA2/PA3 pins. External USB-TTL converter not needed with USART2 module. CubeMX setup requires USART2 module and 80MHz system clock. HAL_UART_Transmit() function used to send serial data
STM32 supports three main boot modes: Main Flash, System Memory, and Embedded SRAM. Boot mode selection depends on Boot0 and Boot1 pin states during reset. Main Flash mode boots from user application storage. System Memory mode uses built-in bootloader for firmware updates. Embedded SRAM mode used for debugging purposes
USB CDC enables communication between STM32 and PC via Virtual COM Port. VCP is Windows interface for accessing various communication channels. STM32 board can operate as CDC device for PC communication
Project programs STM32F103C8 BluePill as USB to Serial converter. Uses ST-Link V2 clone for programming via Arduino IDE. Total cost excluding shipping around US$12
Project created using STM32CubeMx with STM32F103C8T6 board. Clock source set to Crystal/Ceramic Resonator with Serial Wire debug. USB feature enabled through Device(FS) configuration. Clock frequency set to 72 MHz for better performance