 //******************************************************************************
 //* function: spi_0
 //******************************************************************************
-void spi_0()
+void spi_0( void )
 {
   digitalWrite(SPI_CLOCK_PIN, LOW);
   delayMicroseconds(1);

}

//******************************************************************************
//* function: calcFrequencyData
//*         : calculates the frequency value for the syntheziser register B of
//*         : the RTC6751 circuit that is used within the RX5808/RX5880 modules.

//******************************************************************************
//* function: spiEnableHigh
//******************************************************************************
void spiEnableHigh( void )
{
  delayMicroseconds(1);
  digitalWrite(SLAVE_SELECT_PIN, HIGH);
