如何初始化freescale K21的UART0？

Nialu

小弟遇到一个问题，不知道如何初始化k21板子的UART0口，用替他们的原始程序时，当向其发送数据时候，数据寄存器UART0_D一直都不发生变化，想知道如何设置？
void uart_init (UART_MemMapPtr uartch, int sysclk, int baud)
{
    register uint16 sbr, brfa;
    uint8 temp;
   
 /* Enable the clock to the selected UART */   
    if(uartch == UART0_BASE_PTR)
  SIM_SCGC4 |= SIM_SCGC4_UART0_MASK;
    else
     if (uartch == UART1_BASE_PTR)
   SIM_SCGC4 |= SIM_SCGC4_UART1_MASK;
     else
      if (uartch == UART2_BASE_PTR)
       SIM_SCGC4 |= SIM_SCGC4_UART2_MASK;

    /* Make sure that the transmitter and receiver are disabled while we
     * change settings.
     */
    UART_C2_REG(uartch) &= ~(UART_C2_TE_MASK
    | UART_C2_RE_MASK );
                               
//      UART_C2_REG(uartch)=0xff;                         
    /* Configure the UART for 8-bit mode, no parity */
    UART_C1_REG(uartch) = 0x0; /* We need all default settings, so entire register is cleared */
   
    /* Calculate baud settings */
    sbr = (uint16)((sysclk*1000)/(baud * 16));
       
    /* Save off the current value of the UARTx_BDH except for the SBR field */
    temp = UART_BDH_REG(uartch) & ~(UART_BDH_SBR(0x1F));
   
    UART_BDH_REG(uartch) = temp |  UART_BDH_SBR(((sbr & 0x1F00) >> 8));
    UART_BDL_REG(uartch) = (uint8)(sbr & UART_BDL_SBR_MASK);
  
    /* Determine if a fractional divider is needed to get closer to the baud rate */
    brfa = (((sysclk*32000)/(baud * 16)) - (sbr * 32));
   
    /* Save off the current value of the UARTx_C4 register except for the BRFA field */
    temp = UART_C4_REG(uartch) & ~(UART_C4_BRFA(0x1F));
   
    UART_C4_REG(uartch) = temp |  UART_C4_BRFA(brfa);   
    /* Enable receiver and transmitter */
 UART_C2_REG(uartch) |= (UART_C2_TE_MASK
    | UART_C2_RE_MASK );
}
char uart_getchar (UART_MemMapPtr channel)
{
    /* Wait until character has been received */
 
    while (!(UART_S1_REG(channel) & UART_S1_RDRF_MASK));
   
    /* Return the 8-bit data from the receiver */
    return UART_D_REG(channel);
}

/** 
 * \brief   Wait for space in the UART Tx FIFO and then send a character
 * \author  
 * \param    channel  UART channel to send to
*  \param    ch      character to send
 * \return   none
 * \todo   
 * \warning
 */
void uart_putchar (UART_MemMapPtr channel, char ch)
{
    /* Wait until space is available in the FIFO */
    while(!(UART_S1_REG(channel) & UART_S1_TDRE_MASK));
   
    /* Send the character */
    UART_D_REG(channel) = (uint8)ch;
 }
不知道传参怎么弄

我知道答案 目前已有2人回答

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安

IO口配置没有？

Nialu

回复第 2 楼 于2013-09-05 15:40:45发表:
IO口配置没有？ 

管脚都配置好了啊，就是不能够接受发送数据，UART0_D寄存器一直都没有反应

kazamixp

是不是缺了
SIM_SOPT2 |= SIM_SOPT2_UART0SRC(1);//select PLLFLL as uart0 clock source