USTM [Library Function Operation] of STM32F4

07xx embedded four universal synchronous/asynchronous receivers (USART1, USART2, USART3 and USART6) and two universal asynchronous transceivers ( UART4 and UART5). These six interfaces provide IrDASIR ENDEC support for asynchronous communication, multi-machine communication mode, and single-line half-duplex communication mode LIN master/slave function. The USART1 and USART6 interfaces are capable of communicating at speeds up to 10.5 Mbit/s and other available interface communications up to 5.25 bit/s. USART1, USART2, USART3 and USART6 also provide hardware managed CTS, RTS signals, smart card mode (ISO7816 compatible) and similar SPI communication capabilities. All interfaces can be accessed via the DMA controller. Here we only use the simplest serial port settings for the two wires. Hardware environment: STM32F4-Discovery Software environment: MDK4.7a realizes functions: 1. Serial port initialization, 2. Send data through serial port 3. Receive data in interrupt mode, and send back the received data. Using library function operations First, configure NVIC to use NVIC_PriorityGroupConfig() to set priority grouping, and NVIC_Init() to initialize NVIC.