an1069_spi.c

实现dsPIC33FJ256MC710与AVAGO的OPTICAL SENSOR之间的SPI通讯

#include <p33fxxxx.h>
#include "AN1069.h"

/********************************************************************
*     Function Name:    LDByteWriteSPI                              *
*     Parameters:       address & Data            				    *
*     Description:      Writes Data Byte to SPI sensor device       *
*                                                                   *
********************************************************************/
unsigned char LDByteWriteSPI(unsigned char LowAdd, unsigned char Data )
{
  CS = 0;                             // Select Device
  LowAdd = LowAdd | 128;
  WriteSPI1 ( LowAdd );               // write address byte to sensor
  WriteSPI1 ( Data );                 // Write Byte to device
  CS = 1;                             // Deselect device and initiate Write
  SPI1STATbits.SPITBF = 0;
  return ( 0 );
}

/********************************************************************
*     Function Name:    LDByteReadSPI                               *
*     Parameters:       address                                     *
*     Description:      Reads data Byte from SPI sensor device.     *
*                                                                   *
********************************************************************/  
unsigned char LDByteReadSPI(unsigned char LowAdd)
{
  CS = 0;                             // Select Device
  LowAdd = LowAdd & 127;
  WriteSPI1( LowAdd );                // WRITE word address to device
  ReadSPI1();
  CS = 1;                             // Deselect Device
  return ( 0 );                                 
}

/********************************************************************
*     Function Name : WriteSPI1                                     *
*     Description   : This routine writes a single byte/word to     * 
*                     the SPI bus.                                  *
*     Parameters    : Single data byte/word for SPI bus             *
*     Return Value  : None                                          *
********************************************************************/
void WriteSPI1(unsigned int data_out)
{   
    SPI1CON1bits.MODE16 = 0;       
    SPI1BUF = data_out & 0xff;    /*  byte write  */
    while(SPI1STATbits.SPITBF);
    data_out = SPI1BUF;               //Avoiding overflow when reading
}

/******************************************************************************
*     Function Name :   ReadSPI1                                              *
*     Description   :   This function will read single byte/ word  from SPI   *
*                       bus. If SPI is configured for byte  communication     *
*                       then upper byte of SPIBUF is masked.                  *         
*     Parameters    :   None                                                  *
*     Return Value  :   contents of SPIBUF register                           *
******************************************************************************/
unsigned int ReadSPI1()
{         
  SPI1STATbits.SPIROV = 0;
  SPI1BUF = 0x00;                  // initiate bus cycle 
  while(!SPI1STATbits.SPIRBF);
   /* Check for Receive buffer full status bit of status register*/
  if (SPI1STATbits.SPIRBF)
  { 
      SPI1STATbits.SPIROV = 0;              
      SPI1CON1bits.MODE16 = 0;
      return (SPI1BUF & 0xff);    /* return byte read */
  }
  return -1;                  		/* RBF bit is not set return error*/
}