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关于串口通信原理方面的文章：
嵌入式stm32 复习（工作用）— USART（串口）通信原理知识 2020.3.23 添加链接描述
先上完整串口收发部分代码！！！
#include "usart1.h"
#include "stdio.h"
#include "string.h"
#define CR1_OVER8_Set ((u16)0x8000)
u16 USART_GetBound(USART_TypeDef* USARTx, int bound) {
uint32_t integerdivider = 0x00, apbclock = 0x00;
uint32_t tmpreg = 0x00;
uint32_t fractionaldivider = 0x00;
apbclock = 72000000; //如是USART1是72M，否则是36M
/* Determine the integer part */
if ((USARTx->CR1 & CR1_OVER8_Set) != 0) {
/* Integer part computing in case Oversampling mode is 8 Samples */
integerdivider = ((25 * apbclock) / (2 * bound));
} else /* if ((USARTx->CR1 & CR1_OVER8_Set) == 0) */
{
/* Integer part computing in case Oversampling mode is 16 Samples */
integerdivider = ((25 * apbclock) / (4 * bound));
}
tmpreg = (integerdivider / 100) 4));
/* Implement the fractional part in the register */
if ((USARTx->CR1 & CR1_OVER8_Set) != 0) {
tmpreg |= ((((fractionaldivider * 8) + 50) / 100)) & ((uint8_t) 0x07);
} else /* if ((USARTx->CR1 & CR1_OVER8_Set) == 0) */
{
tmpreg |= ((((fractionaldivider * 16) + 50) / 100)) & ((uint8_t) 0x0F);
}
return tmpreg;
}
/**
* @brief USART1 初始化
* @param None
* @retval None
*/
void USART1_Init(int bound) {
//1.使能时钟
RCC->APB2ENR |= 1 APB2ENR |= 1 |