USART最小波特率为2400吗

肖勇 2008-5-28 10:23 楼主

1     2.4     2.399     260.4375     -0.04%     2.3999     1041.6875     0.04%
2     9.6     9.596     65.125     -0.04%     9.599     260.4375     -0.01%
3     19.2     19.193     32.5625     -0.03%     19.203     130.1875     -0.02%
4     57.6     57.471     10.875     -0.22%     57.637     43.375     0.06%
5     115.2     114.942     5.4375     -0.22%     115.274     21.6875     0.06%
6     230.4     232.558     2.6875     -0.94%     229.885     10.875     -0.22%
7     460.8     454.545     1.375     -1.36%     459.77     5.4375     -0.22%
8     921.6     不可能    不可能    不可能    930.232     2.6875     0.94%

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沙发肖勇

补充一问题

USART_InitTypeDef USART_InitStructure;
u8 TxBuffer[] = "ASFGGSGSFGDSFDS";
u8 RxBuffer[TxBufferSize];
u8 TxCounter = 0, RxCounter = 0;
TestStatus TransferStatus = FAILED;
ErrorStatus HSEStartUpStatus;

/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
TestStatus Buffercmp(u8* pBuffer1, u8* pBuffer2, u16 BufferLength);
u8 index = 0;

void SysTick_Config(void);
void LcdShow_Init(void);

/* Private functions ---------------------------------------------------------*/

/*******************************************************************************
* Function Name  : main
* Description    : Main program
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
  debug();
#endif

  /* System Clocks Configuration */
  RCC_Configuration();

  /* NVIC configuration */
  NVIC_Configuration();

  /* Configure the GPIO ports */
  GPIO_Configuration();

    /* Configure the systick */
  SysTick_Config();
  LcdShow_Init();

/* USART1 and USART2 configuration ------------------------------------------------------*/
  /* USART and USART2 configured as follow:
        - BaudRate = 230400 baud
        - Word Length = 8 Bits
        - One Stop Bit
        - Even parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
        - USART Clock disabled
        - USART CPOL: Clock is active low
        - USART CPHA: Data is captured on the second edge
        - USART LastBit: The clock pulse of the last data bit is not output to
                         the SCLK pin
  */
  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_Even;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStructure.USART_Clock = USART_Clock_Disable;
  USART_InitStructure.USART_CPOL = USART_CPOL_Low;
  USART_InitStructure.USART_CPHA = USART_CPHA_2Edge;
  USART_InitStructure.USART_LastBit = USART_LastBit_Disable;

  /* Configure USART1 */
  USART_Init(USART1, &USART_InitStructure);
  /* Configure USART2 */
  USART_Init(USART2, &USART_InitStructure);

  /* Enable the USART1 */
  USART_Cmd(USART1, ENABLE);

  /* Enable the USART2 */
  USART_Cmd(USART2, ENABLE);

  while(TxCounter < TxBufferSize)
  {
    /* Send one byte from USART1 to USART2 */
    USART_SendData(USART1, TxBuffer[TxCounter++]);

    /* Loop until the end of transmit */
    while(USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)
    {
    }

    /* Loop until the USART2 Receive Data Register is not empty */
    while(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == RESET)
    {
    }

    /* Store the received byte in RxBuffer */
    RxBuffer[RxCounter++] = (USART_ReceiveData(USART2) &0x7F );

  }
以上程序是从串口1发送数据ASFGGSGSFGDSFDS到串口2，接受到的数据为什么要与上0x7F（RxBuffer[RxCounter++] = (USART_ReceiveData(USART2)&0x7F );）与上0xFF就有几个数据出错

点赞 2008-5-28 10:33