GD.c
// read 1 byte starting from addr
read 1 byte starting from addr
read 1 byte starting from addr
byte vis_gd_rd(unsigned int addr)
{
  vis_gd_start(addr);
  byte r = vis_spi_transfer(0);
  vis_gd_end();
  return r;
}
byte vis_gd_rd ( unsigned int addr ) { vis_gd_start ( addr ) ; byte r = vis_spi_transfer ( 0 ) ; vis_gd_end ( ) ; return r ; }
read 1 byte starting from addr
read 1 byte starting from addr