STM32 serial communication principle

Parallel communication , For example, transmission 8 position , Then use 8 One pin , Transmit at the same time .

serial communication , transmission 8 position , With one pin , In turn .

Synchronous communication , use cloc The falling edge or rising edge of a clock , To determine sending and receiving .

asynchronous communication , Through the baud rate agreed between the receiving end and the sending end , To determine sending and receiving .

  Full duplex communication is generally , There are independent sending and receiving ports .

Synchronous communication has , Clock signal .

 

USART It can also be used as USRT use .

  The left figure is used between single-chip computers , The right figure is used between MCU and computer , To pass RS232 Level conversion .

 

1、 Accept 、 Send path .

 2、f103, A serial port 1——PCLK2. A serial port 2、3、4、5——PCLK1.

 3、USARTDIV It can be decimal or integer 、 And it has to be 1/16 Integer multiple , Such as 2/16、3/16, because DIV_mantissa、DIV_Fraction.

4、SR Status flag bit during transmission .CR1 On the right 4 position , Enable bit .CR1 On the left 4 position , Interrupt enable bit .