/* FUNCTION ************************************/
uint8_t W5500_spi_read (uint32_t addr)
/*
 ***********************************************/
{
  #define  OPMODE_SREAD  (0x00 | OM10_FDM1)  //  BSB = %00000, RW=0(read), OM =%10
  uint8_t  spi_reg;

  CS_W5500_LOW;   // CS=0, SPI start

  SPI_Transfer (uint8_t)(addr >> 16);  // without CS!
  SPI_Transfer (uint8_t)(addr >>  8);  // without CS!
  SPI_Transfer ( (uint8_t)addr | (OPMODE_SREAD) );   // without CS!
  spi_reg = SPI_Transfer (0);  /* dummy write  */   // without CS!

  CS_W5500_HIGH;  // CS=1, SPI end

  return spi_reg;

} /* --- W5500_spi_read --- */


/* FUNCTION ************************************/
uint8_t W5500_Register_LoopBackTest (void)
/*
 ***********************************************/
{
  uint16_t ii;
  uint8_t  rd_val, err, tmp;

  setMR (MR_RST);     // Reset
  ms_tick_wait (10);  // Delay
  err = getMR ();     // for delay
  ms_tick_wait (200);

  err = 0;
  rd_val = W5500_spi_read (VERSIONR);
  if (rd_val != 4)
  {
    err = 1;
  }

  if (err == 0)
  {
    tmp = getRCR();
    /*  Check R/W capability  */
    for (ii= 2; ii<500; ii++)   // check several times
    {
        setRCR ((uint8_t)ii);   // write Session ID Register in PPPoE mode
        rd_val = getRCR();      // read back Session ID Register
        if (rd_val != (uint8_t)ii)
        {
          err = 1;
          break;
        }
        ms_tick_wait (1);
    };
    setRCR (tmp);
  }
  return  err;

} /* --- W5500_Register_LoopBackTest --- */