閑言少敘，先上代碼，大家看下面這段代碼沒有問題？

// Note: USART demo code runs on STM32F030
#include "main.h"

static __IO uint32_t TimingDelay;

RCC_ClocksTypeDef RCC_Clocks;

uint8_t uart_buffer;

// GPIO Configuration
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_1); // Tx PA9
GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_1); // Rx PA10
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10; // USART1_TX | USART1_RX
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_Level_1;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}

// USART Configuration
void USART_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
USART_InitStructure.USART_BaudRate = 115200;
//USART_InitStructure.USART_BaudRate = 9600;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
USART_Init(USART1,&USART_InitStructure);
USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
USART_Cmd(USART1,ENABLE);
}

// Interrupt Configuration
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
// USART1 interrupt Config
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}

// USART1 Interrupt Handler
void USART1_IRQHandler (void)
{
static uint8_t i = 0;

if(USART_GetITStatus(USART1,USART_IT_RXNE)!= RESET)
{// Clear Receive Data Register Not Empty Flag
USART_ClearITPendingBit(USART1,USART_IT_RXNE);
uart_buffer[i++] = USART_ReceiveData(USART1);
if(i == 100)
i = 0;
}
}

int main(void)
{
static uint8_t ch;

// Init a 1ms timer interrupt, for Delay function implementation.
RCC_GetClocksFreq(&RCC_Clocks);
SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);

// Enable USART1 and GPIOA clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,ENABLE);

GPIO_Configuration();
USART_Configuration();
NVIC_Configuration();

ch = 'A';

while(1)
{
Delay(50);
while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
USART_SendData(USART1, ch);
ch++;
}

}

/**
* @brief Inserts a delay time.
* @param nTime: specifies the delay time length, in 1 ms.
* @retval None
*/
void Delay(__IO uint32_t nTime)
{
TimingDelay = nTime;

while(TimingDelay != 0);
}

/**
* @brief Decrements the TimingDelay variable.
* @param None
* @retval None
*/
void TimingDelay_Decrement(void)
{
if(TimingDelay != 0x00)
{
TimingDelay--;
}
}

它可以在 STM32F030 上調(diào)試通過的發(fā)送測試程序，發(fā)送采用接收循環(huán)??，接收到接收的數(shù)據(jù)存入?yún)f(xié)議。

有很多比較認真的實戰(zhàn)派的同學估計會下載子上跑一跑，它確實能跑通，看起來也沒什么問題。很多教程甚至官方的都是類似的處理方法。

這確實是在某個像馬坑里有馬兒跑出來的馬兒，然后跑著一個人跑出來，跑出來連挖挖挖出來。 ，莫名更新了它的死機。查來查去，查去查來，發(fā)現(xiàn)問題。解決起來不容易啊，一個去開，拆代碼，想都。。。

所以同學們不要輕視任何一段代碼?。?/p>

非?？斓臅r候，如果對方接收到數(shù)據(jù)的時候，可以自己發(fā)送接收數(shù)據(jù)的時間，或者對方正在發(fā)送的數(shù)據(jù)發(fā)送給對方。 ，會導致超出標志位的置位。這個標志位一置，原來就亂了。所以，在程序中一定要對異常情況的處理。甚至覺得發(fā)生的異常也不要置之不理。（一想為什么要填充Flash的空白區(qū)域？在正常情況代碼永遠不會跑到空白區(qū)域下是吧。）

對串口異常的處理也可以參考下面的處理函數(shù)。當然可以在主程序中處理，以便在代碼中斷的情況下正常運行。

// USART1 Interrupt Handler
void USART1_IRQHandler (void)
{
static uint8_t i = 0;

if(USART_GetFlagStatus(USART1, USART_FLAG_ORE) != RESET)
{// Clear Overrun Error Flag
USART_ClearFlag(USART1, USART_FLAG_ORE);
}
else if(USART_GetFlagStatus(USART1, USART_FLAG_NE) != RESET)
{// Clear Noise Error Flag
USART_ClearFlag(USART1, USART_FLAG_NE);
}
else if(USART_GetFlagStatus(USART1, USART_FLAG_FE) != RESET)
{// Clear Framing Error Flag
USART_ClearFlag(USART1, USART_FLAG_FE);
}
else if(USART_GetFlagStatus(USART1, USART_FLAG_PE) != RESET)
{// Clear Parity Error Flag
USART_ClearFlag(USART1, USART_FLAG_PE);
}
else if(USART_GetITStatus(USART1,USART_IT_RXNE)!= RESET)
{// Clear Receive Data Register Not Empty Flag
USART_ClearITPendingBit(USART1,USART_IT_RXNE);
uart_buffer[i++] = USART_ReceiveData(USART1);
if(i == 100)
i = 0;
}
}


審核編輯：劉清