(1)
The direction of the bean is set to input.

 MAIN.C

void main(void)
{
  /* Wait until "10101010" is on the low port,
     "01010101" is on the middle port and 
     "00010001" is on the high port */
  while( Bt31_GetVal() != 0x1155AA );
    :
}

(2)
The direction of the bean is set to output.

 MAIN.C

void main(void)
{
  Bt31_PutVal(0x1155AA);
  /* "10101010" is on the low port,
     "01010101" is on the middle port and 
     "00010001" is on the high port */
  
  for (;;) {
  /* Invert output level of second pin on the high port */
    Bt31_NegBit(17);
  }
}

(3)
The direction of the bean is set to input/output.

 MAIN.C

void main(void)
{
  Bt31_SetDir(FALSE);  // Set input mode

  /* Wait until "0xFFFFFF" is on the ports */
  while( Bt31_GetVal() != 0xFFFFFF );
  
  Bt31_SetDir(TRUE);   // Set output mode

  Bt31_PutVal(0);      // Set "0x000000" on the ports
}