串口

5 加了一个空线程，串口接收数据会丢失字节

发布于 2021-04-12 15:46:03 浏览：695 订阅该版

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给你这个改动的地方提供一些资料，不知道能不能帮助你更好地理解参数的意义。
你现在将USART_IT_RXNE改成USART_FLAG_RXNE。在STM32中这个二个参数的定义是：
#define USART_FLAG_RXNE                 ((uint32_t)USART_SR_RXNE)
#define USART_SR_RXNE                       USART_SR_RXNE_Msk 
对应的是USART_SR寄存器的的RXNE，寄存器描述如下：
RXNE: Read data register not empty
This bit is set by hardware when the content of the RDR shift register has been transferred to the USART_DR register. An interrupt is generated if RXNEIE=1 in the USART_CR1 register. 
It is cleared by a read to the USART_DR register. The RXNE flag can also be cleared by 
writing a zero to it. This clearing sequence is recommended only for multibuffer 
communication.
0: Data is not received
1: Received data is ready to be read.
请注意，它是硬件复位，就是当移位寄存器将数据放入数据寄存器中后，就会产生中断。而当你读取数据寄存器后自动清零。
#define USART_IT_RXNE                   ((uint32_t)(USART_CR1_REG_INDEX << 28U | USART_CR1_RXNEIE))
#define USART_CR1_RXNEIE                    USART_CR1_RXNEIE_Msk
对应的是USART_CR1寄存器的的RXNEIE:寄存器的描述如下：
RXNEIE: RXNE interrupt enable
This bit is set and cleared by software.
0: Interrupt is inhibited
1: A USART interrupt is generated whenever ORE=1 or RXNE=1 in the USART_SR register
注意：这个是控制寄存器设置位，通过设置1和0来打开关闭串口中断接受。一般我们在程序初始化的时候设置。

所有你原来的标志一定是错了，但修改成USART_FALG_RXNE，我觉得看你的用法。接受FIFO可以是多个字节触发，如果只是一个字节。这个添加就没有意义。但如果你的串口采用的是DMA方式，则可以考虑软件写0来清除标志。这里只是个人建议，希望能有帮助。