Question

我是ST世界的新人。我正在尝试使用UART，所以我编写了这段代码来初始化UART并发送“Hello”。我正在使用STM32F0板。

#include "stm32f0xx_gpio.h"
#include "stm32f0xx_rcc.h"
#include "stm32f0xx_misc.h"
#include "stm32f0xx_usart.h"

#define UINT8               uint8_t
#define UINT32              uint32_t


#define MAX_BUFFER_SIZE     256

typedef struct Buffer_st
{
   UINT8 size;
   UINT8 data[MAX_BUFFER_SIZE];
}Buffer_st;

Buffer_st receivedDataUART1;

void initUART1(UINT32 baudRate)
{
   NVIC_InitTypeDef NVIC_InitStructure;
   GPIO_InitTypeDef GPIO_InitStructure;
   USART_InitTypeDef USART_InitStructure;

   /* Enable the USART1 Interrupt */
   NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
   NVIC_InitStructure.NVIC_IRQChannelPriority = 0;
   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStructure);

   //UART init
   USART_InitStructure.USART_BaudRate = baudRate;
   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_Rx | USART_Mode_Tx;

   /* Enable GPIO clock */
   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

   /* Enable USART clock */
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

   /* Connect PXx to USARTx_Tx */
   GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);

   /* Connect PXx to USARTx_Rx */
   GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1);

   /* Configure USART Tx, Rx as alternate function push-pull */
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
   GPIO_Init(GPIOA, &GPIO_InitStructure);

   /* USART configuration */
   USART_Init(USART1, &USART_InitStructure);

   /* Enable USART */
   USART_Cmd(USART1, ENABLE);
   USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

   resetReceivedDataBufferUART1();
}

void resetReceivedDataBufferUART1(void)
{
   receivedDataUART1.size = 0;
   memset(receivedDataUART1.data, MAX_BUFFER_SIZE, 0);
}

UINT8 sendDataUART1(Buffer_st buffer)
{
  UINT8 cpt;

  for (cpt = 0; cpt < buffer.size; cpt++)
  {
     USART_SendData(USART1, buffer.data[cpt]);

     //Loop until the end of transmission
     while (USART_GetFlagStatus(USART1, USART_IT_TXE) == RESET);
  }
}

void USART1_IRQHandler(void)
{
   if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
   {
       receivedDataUART1.data[receivedDataUART1.size++] = USART_ReceiveData(USART1);
   }
}

int main(void)
{
   Buffer_st buffer = {6,"Hello"};

   initUART1(9600);
   sendDataUART1(buffer);

   while(1);
   return 0;
}

我正在使用UART / USB连接器。问题是我在minicom中没有收到任何东西。调试时我发现progrom进入无限循环

 //Loop until the end of transmission
while (USART_GetFlagStatus(USART1, USART_IT_TXE) == RESET);

Answer 1

您正在将中断状态标志与用于同步轮询的标志混合在一起。要发送数据，您必须首先轮询USART_FLAG_TXE标志以获取发送数据寄存器空状态，然后您可以发送您的字节。 USART_IT_TXE标志仅供中断使用。

因此，要发送一个字节，请执行以下操作：

while(USART_GetFlagStatus(USART1,USART_FLAG_TXE)!=SET);
USART_SendData(USART1,myByte);

有关详细信息，请参阅RM0091中USARTx_ISR注册的文档。

Answer 2

你使用这样的功能

void USART_write(unsigned char *string){

    while(*string){
        // wait until data register is empty
        while( !(USART1->SR & 0x00000040) );
        USART_SendData(USART1,*string);
        *string++;
    }
}

此代码在STM3VLDiscovery上进行测试。您必须检查芯片的寄存器状态，例如（！（USART1-＆gt; SR＆amp; 0x00000040））;

STM32F0 UART无法正常工作

2 个答案: