Freescale 飞思卡尔使用UART中断，单线UART

最新推荐文章于 2025-09-04 23:41:56 发布

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本文档介绍了如何使用CRSF库进行串口通信，包括设置波特率、配置CRSF读写回调、清除错误状态、发送数据以及关闭串口。涉及函数如`setup_crsf_serial_port`、`uart_clear_error`和`crsf_send_data`，展示了串口操作的关键步骤。

void setup_crsf_serial_port(uint32_t baud,crsf_read_cb_t read_cb)
{

  if(g_crsf_read_callback==0)
  {
        g_crsf_read_callback = read_cb;
      //uart_single_init(bdrate,DEFAULT_SYSTEM_CLOCK,bdrate);//Set single wire mode.
      SIM->SCGC4 |= SIM_SCGC4_UART2_MASK;// Enable the clock to the selected UART
  
      /*
      Make sure that the transmitter and receiver are disabled while we 
         * change settings.*/
      UART2->C2 &= ~(UART_C2_TE_MASK|UART_C2_RE_MASK);
        /* Configure single wire ,  8-bit mode, no parity*/
      UART2->C1  |= (UART_C1_LOOPS_MASK | UART_C1_RSRC_MASK);    
   
      /* Calculate baud settings */
      uint16_t  sbr = (uint16_t)(DEFAULT_SYSTEM_CLOCK/2/(baud *16));
  
      /* Save off the current value of the UARTx_BDH except for the SBR field */
        /* Save off the current value of the UARTx_BDH except for the SBR field */

        uint8_t temp =   UART2->BDH & (~UART_BDH_SBR(0x1F)); 
        UART2->BDH= temp |  UART_BDH_SBR(((sbr & 0x1F00) >> 8));
        UART2->BDL = (uint8_t)(sbr & UART_BDL_SBR_MASK);

        #if 0
        /* Determine if a fractional divider is needed to get closer to the baud rate */
        uint16_t brfa = (((DEFAULT_SYSTEM_CLOCK*32000)/(baud * 16)) - (sbr * 32));

        /* Save off the current value of the UARTx_C4 register except for the BRFA field */
        temp = UART2->C4 & ~(0x1F);
        UART2->C4 = temp |  brfa;    
        #endif

        /* Enable receiver and transmitter, and enable receive */
        UART2->C2 |= (UART_C2_TE_MASK|UART_C2_RE_MASK);
    
        //uart inverted 
        UART2->C3 |= UART_C3_TXINV_MASK;
        UART2->S2 |= UART_S2_RXINV_MASK;
        NVIC_EnableIRQ(UART2_IRQn);
    }
    
}
bool uart_clear_error()
{
   bool has_error = false;
  if(UART2->S1 & UART_S1_OR_MASK  )
    {
        //To clear OR,write a logic 1 to the OR flag.
        UART2->S1  |= UART_S1_OR_MASK;
        has_error = true ;
    }
    //clear all 
    if(  UART2->S1 & UART_S1_FE_MASK  )
    {
        UART2->S1  |= UART_S1_FE_MASK;
         has_error = true ;
    }

   if(  UART2->S1 & UART_S1_PF_MASK  )
    {
        UART2->S1  |= UART_S1_PF_MASK;
         has_error = true ;
    }

    
   if(  UART2->S1 & UART_S1_NF_MASK  )
    {
        UART2->S1  |=UART_S1_NF_MASK;
         has_error = true ;
    }
    return has_error;
}

uint8_t  *g_crsf_send_buf= 0;
uint32_t g_crsf_send_len = 0;
uint32_t g_crsf_send_pos = 0;


void crsf_send_data(uint8_t *buf, uint32_t len)
{


uint8_t dat;
  cli();
    //while(!(UART2->S1&UART_S1_TDRE_MASK));
    //while(!(UART2->S1 & UART_S1_TC_MASK));
  //  PTE->PDDR |= 1C2 &=~(UART_C2_RIE_MASK);
    UART2->C3 &=~(UART_C3_ORIE_MASK);


    UART2->C3 |= UART_C3_TXDIR_MASK;
#if USE_IE_UART_TX
    g_crsf_send_buf = buf;
    g_crsf_send_len = len;
    g_crsf_send_pos =0;
    UART2->C2 |= UART_C2_TIE_MASK;
#else
    for(int i=0;iS1&UART_S1_TDRE_MASK));
      UART2->D = buf[i];
    
    }
    
    while(!(UART2->S1 & UART_S1_TC_MASK))
    {
    }
    
   
     UART2->C3 &= ~UART_C3_TXDIR_MASK;
    /* Configure the module1 TXD pin as an input */
 //   PTE->PDDR &= ~(1C3 &= ~UART_C3_TXDIR_MASK;
    UART2->C2 |=UART_C2_RIE_MASK;
 #endif
    // UART_EnableInterrupts(UART2, kUART_RxDataRegFullInterruptEnable| kUART_RxOverrunInterruptEnable);
     sei();
}

#if 1
void UART2_IRQHandler(void )
{
#if USE_IE_UART_TX
     if(!UART2->C3 & UART_C3_TXDIR_MASK)
  #endif
    {
      uint8_t dat;
      if(uart_clear_error())
      {
        dat = UART2->D;
        return;
      }
    }

    if(UART2->S1 & UART_S1_RDRF_MASK)
    {
        uint8_t dat = UART2->D;
        if(g_crsf_read_callback)
        {
            (*g_crsf_read_callback)(dat);
        }

    }
 #if USE_IE_UART_TX
    else if(UART2->S1 & UART_S1_TDRE_MASK)
    {
         if(g_crsf_send_pos < g_crsf_send_len)
         {
            UART2->D = g_crsf_send_buf[g_crsf_send_pos++];
         }
         else{
             while(!(UART2->S1 & UART_S1_TC_MASK))
            {
            }
    
           UART2->C2 &=  ~UART_C2_TIE_MASK;
           UART2->C3 &= ~UART_C3_TXDIR_MASK;
           UART2->C2 |=UART_C2_RIE_MASK;
         }
       
    }
 #endif
  
 
}
#endif

void shutdown_crsf_serial_port()
{
  if(  g_crsf_read_callback != NULL)
  {
     g_crsf_read_callback = NULL;
     UART2->C2 &= ~(UART_C2_RE_MASK|UART_C2_RIE_MASK|UART_C2_TE_MASK|UART_C2_TIE_MASK);
     UART2->C3 &=~(UART_C3_ORIE_MASK);
     NVIC_DisableIRQ(UART2_IRQn);
     SIM->SCGC4 &=~SIM_SCGC4_UART2_MASK;
  }
}


int  crsf_is_sending()
{
    if(UART2->C3 & UART_C3_TXDIR_MASK)
        return 1;
    return 0;
}