GD.c
// start an spi transaction to addr
start an spi transaction to addr
start an spi transaction to addr
void vis_gd_start(unsigned int addr)
{
  SPI_PORT &= ~(1 << SPI_SS_PIN); 
  vis_spi_transfer(highByte(addr));
  vis_spi_transfer(lowByte(addr));
}
void vis_gd_start ( unsigned int addr ) { SPI_PORT &= ~ ( 1 << SPI_SS_PIN ) ; vis_spi_transfer ( highByte ( addr ) ) ; vis_spi_transfer ( lowByte ( addr ) ) ; }
start an spi transaction to addr
start an spi transaction to addr
// start communicating with SPI slave