getsspi2.c

Microchip的官方PIC24H系列16位单片机的外设源程序库。

#include <p30fxxxx.h>
#include <spi.h>

/***************************************************************************
*     Function Name :  getsSPI2                                            *
*     Description   :  This routine reads a string from the SPI            *
*                      receive buffer.The number of byte/word to be read   *
                       is determined by parameter 'length'                 *
*     Parameters    :  unsigned int length: The length of data expected    *
*                      unsigned int *rdptr   the received data to be 
*                      recorded to this array
*                      unsigned int uart_data_wait timeout value
*     Return Value  :  unsigned int number of data bytes yet to be received*                     
****************************************************************************/

/* The following devices support SPI2 */
#if defined(__dsPIC30F6010__) || defined(__dsPIC30F5011__)  || defined(__dsPIC30F6011__) || \
    defined(__dsPIC30F6012__) || defined(__dsPIC30F5013__) ||  defined(__dsPIC30F6013__) || \
    defined(__dsPIC30F6014__) || defined(__dsPIC30F5015__)  

unsigned int getsSPI2(unsigned int length, unsigned int *rdptr, unsigned int spi_data_wait)
{
    int wait = 0;
    char *temp_ptr = (char *)rdptr;
    while (length)                         /* stay in loop until length = 0  */
    {
        while(!DataRdySPI2())
        {

           if(wait < spi_data_wait)
              wait++ ;                     /* wait for time out operation */
           else
              return(length);              /* Time out, return number of byte/word read 
                                              for a given length */
        }
        wait = 0;
        if(SPI2CONbits.MODE16)
            *rdptr++ = getcSPI2();         /* read a single word */
        else
            *temp_ptr++ = getcSPI2();      /* read a single byte */
        length--;                          /* reduce string length count by 1*/
    }

    return (length);                       /* return number of byte/word to be read i.e, 0 */
}

#endif