comm.c

串口通信构件

/*
*********************************************************************************************************
*                                     Embedded Systems Building Blocks
*                                  Complete and Ready-to-Use Modules in C
*串行口通信程序
*********************************************************************************************************
*/

/*
*********************************************************************************************************
*                                               INCLUDES
*********************************************************************************************************
*/

#include "..\includes\INCLUDES.H"
extern bit SemTIbusy;
/*
*********************************************************************************************************
*                                               DATA TYPES
*********************************************************************************************************
*/
    idata INT8U   RingBufRxCtr;                   /* Number of characters in the Rx ring buffer              */
    idata INT8U  *RingBufRxInPtr;                 /* Pointer to where next character will be inserted        */
    idata INT8U  *RingBufRxOutPtr;                /* Pointer from where next character will be extracted     */
    idata INT8U   RingBufRx[COMM_RX_BUF_SIZE];    /* Ring buffer character storage (Rx)                      */
    idata INT8U   RingBufTxCtr;                   /* Number of characters in the Tx ring buffer              */
    idata INT8U  *RingBufTxInPtr;                 /* Pointer to where next character will be inserted        */
    idata INT8U  *RingBufTxOutPtr;                /* Pointer from where next character will be extracted     */
    idata INT8U   RingBufTx[COMM_TX_BUF_SIZE];    /* Ring buffer character storage (Tx)                      */

/*
*********************************************************************************************************
*                                            GLOBAL VARIABLES
*********************************************************************************************************
*/
/*
*********************************************************************************************************
*                                    REMOVE CHARACTER FROM RING BUFFER
*
*从接收缓冲区取数，应用中取数
* Description : This function is called by your application to obtain a character from the communications
*               channel.
* Arguments                 'err'   is a pointer to where an error code will be placed:
*                           *err is set to COMM_NO_ERR   if a character is available
*                           *err is set to COMM_RX_EMPTY if the Rx buffer is empty
*                           *err is set to COMM_BAD_CH   if you have specified an invalid channel
* Returns     : The character in the buffer (or NUL if the buffer is empty)
*********************************************************************************************************
*/
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
    extern OS_CPU_SR  cpu_sr;
#endif

INT8U  CommGetChar (INT8U *err)
{
    INT8U          c;
    OS_ENTER_CRITICAL();
    if (RingBufRxCtr > 0) {                          /* See if buffer is empty                   */
        RingBufRxCtr--;                              /* No, decrement character count            */
        c = *RingBufRxOutPtr++;                      /* Get character from buffer                */
        if (RingBufRxOutPtr == &RingBufRx[COMM_RX_BUF_SIZE]) {     /* Wrap OUT pointer     */
            RingBufRxOutPtr = &RingBufRx[0];
        }
        OS_EXIT_CRITICAL();
        *err = COMM_NO_ERR;
        return (c);
    } else {
        OS_EXIT_CRITICAL();
        *err = COMM_RX_EMPTY;
        c    = NUL;                                        /* Buffer is empty, return NUL              */
        return (c);
    }
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                  GET TX CHARACTER FROM RING BUFFER
*
*从发送缓冲区取数,中断中发数调用
* Description : This function is called by the Tx ISR to extract the next character from the Tx buffer.
*               The function returns FALSE if the buffer is empty after the character is extracted from
*               the buffer.  This is done to signal the Tx ISR to disable interrupts because this is the
*               last character to send.
* Arguments                 'err'   is a pointer to where an error code will be deposited:
*                           *err is set to COMM_NO_ERR         if at least one character was left in the
*                                                              buffer.
*                           *err is set to COMM_TX_EMPTY       if the Tx buffer is empty.
*                           *err is set to COMM_BAD_CH         if you have specified an incorrect channel
* Returns     : The next character in the Tx buffer or NUL if the buffer is empty.
*********************************************************************************************************
*/

INT8U  CommGetTxChar (INT8U *err)
{
    INT8U          c;
    if (RingBufTxCtr > 0) {                          /* See if buffer is empty                   */
        RingBufTxCtr--;                              /* No, decrement character count            */
        c = *RingBufTxOutPtr++;                      /* Get character from buffer                */
        if (RingBufTxOutPtr == &RingBufTx[COMM_TX_BUF_SIZE]) {     /* Wrap OUT pointer     */
            RingBufTxOutPtr = &RingBufTx[0];
        }
        *err = COMM_NO_ERR;
        return (c);                                        /* Characters are still available           */
    } else {
        *err = COMM_TX_EMPTY;
        return (NUL);                                      /* Buffer is empty                          */
    }
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                  INITIALIZE COMMUNICATIONS MODULE
*
*
* Description : This function is called by your application to initialize the communications module.  You
*               must call this function before calling any other functions.
* Arguments   : none
*********************************************************************************************************
*/

void  CommInit(void)
{
    RingBufRxCtr    = 0;
    RingBufRxInPtr  = &RingBufRx[0];
    RingBufRxOutPtr = &RingBufRx[0];
    RingBufTxCtr    = 0;
    RingBufTxInPtr  = &RingBufTx[0];
    RingBufTxOutPtr = &RingBufTx[0];
}
void  CommRxInit(void)
{
    RingBufRxCtr    = 0;
    RingBufRxInPtr  = &RingBufRx[0];
    RingBufRxOutPtr = &RingBufRx[0];
}
/*
void  CommTxInit(void)
{
    RingBufTxCtr    = 0;
    RingBufTxInPtr  = &RingBufTx[0];
    RingBufTxOutPtr = &RingBufTx[0];
}
*/
/*$PAGE*/
/*
*********************************************************************************************************
*                                  SEE IF RX CHARACTER BUFFER IS EMPTY
*测试接收缓冲区是否为空
*
* Description : This function is called by your application to see if any character is available from the
*               communications channel.  If at least one character is available, the function returns
*               FALSE otherwise, the function returns TRUE.
* Returns     : TRUE    if the buffer IS empty.
*               FALSE   if the buffer IS NOT empty or you have specified an incorrect channel
*********************************************************************************************************
*/

BOOLEAN  CommIsEmpty ()
{
    BOOLEAN        empty;
    OS_ENTER_CRITICAL();
    if (RingBufRxCtr > 0) {                          /* See if buffer is empty                   */
        empty = FALSE;                                     /* Buffer is NOT empty                      */
    } else {
        empty = TRUE;                                      /* Buffer is empty                          */
    }
    OS_EXIT_CRITICAL();
    return (empty);
}


/*
*********************************************************************************************************
*                                   SEE IF TX CHARACTER BUFFER IS FULL
*测试发送缓区是否满?
*
* Description : This function is called by your application to see if any more characters can be placed
*               in the Tx buffer.  In other words, this function check to see if the Tx buffer is full.
*               If the buffer is full, the function returns TRUE otherwise, the function returns FALSE.
* Returns     : TRUE    if the buffer IS full.
*               FALSE   if the buffer IS NOT full or you have specified an incorrect channel
*********************************************************************************************************
*/

BOOLEAN  CommIsFull ()
{
    BOOLEAN        full;

    OS_ENTER_CRITICAL();
    if (RingBufTxCtr < COMM_TX_BUF_SIZE) {           /* See if buffer is full                    */
        full = FALSE;                                      /* Buffer is NOT full                       */
    } else {
        full = TRUE;                                       /* Buffer is full                           */
    }
    OS_EXIT_CRITICAL();
    return (full);
}


/*
*********************************************************************************************************
*                                            OUTPUT CHARACTER
*
*向发送缓冲区放数
* Description : This function is called by your application to send a character on the communications
*               channel.  The character to send is first inserted into the Tx buffer and will be sent by
*               the Tx ISR.  If this is the first character placed into the buffer, the Tx ISR will be
*               enabled.  If the Tx buffer is full, the character will not be sent (i.e. it will be lost)
* Arguments     'c'     is the character to send.
* Returns     : COMM_NO_ERR   if the function was successful (the buffer was not full)
*               COMM_TX_FULL  if the buffer was full
*               COMM_BAD_CH   if you have specified an incorrect channel
*********************************************************************************************************
*/

INT8U  CommPutChar (INT8U c)
{
    if(RingBufTxCtr == 0) {
        while(SemTIbusy);    
    }
    OS_ENTER_CRITICAL();
    if (RingBufTxCtr < COMM_TX_BUF_SIZE) {           /* See if buffer is full                    */
        RingBufTxCtr++;                              /* No, increment character count            */
        *RingBufTxInPtr++ = c;                       /* Put character into buffer                */
        if (RingBufTxInPtr == &RingBufTx[COMM_TX_BUF_SIZE]) { /* Wrap IN pointer           */
            RingBufTxInPtr = &RingBufTx[0];
        }
        if (RingBufTxCtr == 1) {                     /* See if this is the first character       */
            CommTxIntEn();                    /* Yes, Enable Tx interrupts                */
            OS_EXIT_CRITICAL();
        } else {
            OS_EXIT_CRITICAL();
        }
        return (COMM_NO_ERR);
    } else {
        OS_EXIT_CRITICAL();
        return (COMM_TX_FULL);
    }
}

/*
*********************************************************************************************************
*                                    INSERT CHARACTER INTO RING BUFFER
*
*向接收缓冲区放数（接收中断调用）
* Description : This function is called by the Rx ISR to insert a character into the receive ring buffer.
* Arguments   : 'c'     is the character to insert into the ring buffer.  If the buffer is full, the
*                       character will not be inserted, it will be lost.
*********************************************************************************************************
*/

void  CommPutRxChar (INT8U c)
{
    if (RingBufRxCtr < COMM_RX_BUF_SIZE) {           /* See if buffer is full                    */
        RingBufRxCtr++;                              /* No, increment character count            */
        *RingBufRxInPtr++ = c;                       /* Put character into buffer                */
        if (RingBufRxInPtr == &RingBufRx[COMM_RX_BUF_SIZE]) { /* Wrap IN pointer           */
            RingBufRxInPtr = &RingBufRx[0];
        }
    }
}