sci.c

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#include "app.h"

BYTE SCI_Init(DWORD baud, BYTE ninebits)
{
    int X;
    DWORD tmp;
    
    /* calculate and set baud rate register */
    /* for asynchronous mode */
    tmp = 16UL * baud;
    X = (int)(FOSC/tmp) - 1;
    if((X>255) || (X<0))
    {
        tmp = 64UL * baud;
        X = (int)(FOSC/tmp) - 1;
        if((X>255) || (X<0))
        {
            return TRUE;    /* panic - baud rate unobtainable */
        }
        else
            BRGH = CLEAR;   /* low baud rate */
    }
    else
        BRGH = SET; /* high baud rate */
    SPBRG = X;  /* set the baud rate */

    SYNC = CLEAR;   /* asynchronous */
    SPEN = ENABLE;  /* enable serial port pins */
    CREN = ENABLE;  /* enable reception */
    SREN = CLEAR;   /* no effect */
    TXIE = DISABLE; /* disable tx interrupts */
    RCIE = DISABLE; /* disable rx interrupts */
    TX9  = ninebits?SET:CLEAR;  /* 8- or 9-bit transmission */
    RX9  = ninebits?SET:CLEAR;  /* 8- or 9-bit reception */
    TXEN = ENABLE;  /* enable the transmitter */

    return FALSE;
} 

//#pragma interrupt_level 1
void SCI_Write(BYTE byte)
{
    while(!TXIF)    /* set when register is empty */
        continue;
    TXREG = byte;

    return;
}

BYTE SCI_Read(void)
{
    while(!RCIF)    /* set when register is not empty */
        continue;

    return RCREG;   /* RXD9 and FERR are gone now */
} 

BYTE SCI_CheckOverrun(void)
{
    if(OERR)    // re-enable after overrun error 
    {
        CREN = DISABLE;
        CREN = ENABLE;
        return TRUE;
    }
    
    return FALSE;
} 

//*****************************************************************************[ENDL]***************