$DD03/56579/CIA2+3:   Data Direction Register B

   +----------+---------------------------------------------------+
   | Bit  x   |   1 = Pin PBx set to Output, 0 = Input            |
   +----------+---------------------------------------------------+

   Default Value: $00/0 (%00000000)

Kernal-Reference:

 STA $DD03   : $F48A
 STX $DD03   : $FDC1