Need a clock synchronous communication line to synchronize time, and asynchronous communication is agreed by baud rate data receiving and pored over time,
STM32 serial port communication pins, also want to set, specific the pin can be set to a serial port communication pins, also need to see the use model of chip manual,
A serial port communication defines the contents of the packet, it from the start bit, the main data bits, parity, stop bits, the two sides agreed to good to normal communication
Familiar with the function diagram of the USART
Specific functional block diagram of each part in detail, you can refer to the wildfires books "STM32 library development practical guide"
Familiar with the function block diagram, programming is a direction about
And then there are the familiar, USART structure,
Then the rest of the 51 single-chip microcomputer and the same